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Informacje o czasopiśmie
Format
Czasopismo
eISSN
1899-7562
Pierwsze wydanie
13 Jan 2009
Częstotliwość wydawania
5 razy w roku
Języki
Angielski

Wyszukiwanie

Tom 65 (2018): Zeszyt 1 (December 2018)

Informacje o czasopiśmie
Format
Czasopismo
eISSN
1899-7562
Pierwsze wydanie
13 Jan 2009
Częstotliwość wydawania
5 razy w roku
Języki
Angielski

Wyszukiwanie

27 Artykułów

Section I - Kinesiology

Otwarty dostęp

Test-Retest Reliability of Isokinetic Arm Strength Measurements in Competitive Swimmers

Data publikacji: 31 Dec 2018
Zakres stron: 5 - 11

Abstrakt

Abstract

Swimming motor patterns lead internal rotators to grow stronger than antagonist muscles, what may increase the risk of injury in swimmers. Injury prevention often involves the improvement of external rotators strength, as well as the external rotation/internal rotation ratio. The current research aimed to evaluate the test-retest reliability of shoulder concentric rotation strength in competitive swimmers using an isokinetic dynamometer. The study enrolled 35 competitive swimmers aged between 13 and 19 years. Concentric movements were performed including internal and external rotations of the shoulder joint following the instructions of the standardized protocol. The angular velocity of the test was defined at 60º/s. Outcome measures were peak torque (Nm) and work (J), measured in both, the dominant and non-dominant arms. The external rotation/internal rotation ratio was also calculated. Reliability was excellent for peak torque and work. For the external rotation/internal rotation ratio, the ICC oscillated between 0.744 and 0.860 for the work ratio of the non-dominant arm and the peak torque ratio of the dominant arm, respectively. In general terms, better reliability was observed for peak torque compared with work, for external rotation compared with internal rotation, and for the dominant arm compared with the non-dominant one.

Key words

  • reliability
  • swimming
  • injury prevention
  • sport injuries
  • peak torque
Otwarty dostęp

Neurocognitive Functioning of Sport Climbers

Data publikacji: 31 Dec 2018
Zakres stron: 13 - 19

Abstrakt

Abstract

Sport climbing, included in the programme of the Tokyo 2020 Summer Olympic Games, is increasingly gaining in popularity as a method of physical and mental health enhancement. Studies show a positive relationship between climbing and improvement of neurocognitive functioning. The aim of this study was to determine the differences in neurocognitive indicators: time of testing, memory, and location between climbers and non-climbers. The sample comprised 30 sport climbers (15 males, 15 females; aged 25 ± 4 years) practicing climbing regularly for five years, and 30 non-climbing age- and sex-matched controls. The Tactual Performance Test (Halstead-Reitan Test Battery) was used to measure neurocognitive functions (tactile-spatial functions, motion coordination, kinesthetic abilities, learning, memory). Significant differences were found between sport climbers and controls in reference to time, memory, and location (p < 0.05). Climbers reached higher memory as well as location ratios and lower time ratios in comparison to controls. Different strategies used to complete the task between the two groups were observed. The neurocognitive functioning of sport climbers manifests itself in faster recognition and differentiation of tactile input and better spatial perception, tactile perception, and movement memory.

Key words

  • neurocognitive functioning
  • sport climbing
  • Tactual Performance Test
Otwarty dostęp

The Influence of Verbal Instruction on Measurement Reliability and Explosive Neuromuscular Performance of the Knee Extensors

Data publikacji: 31 Dec 2018
Zakres stron: 21 - 34

Abstrakt

Abstract

The current study aimed to examine the effect of verbal instruction on explosive force production and between-session measurement reliability during maximal voluntary contractions of knee extensors. Following familiarization, 20 healthy males performed 3 maximal contractions with a “hard-and-fast” instruction and 3 maximal contractions with a “fast” instruction during 2 test-retest sessions. Knee extension maximal voluntary force (Fmax) and the maximal rate of force development (RFDmax) were measured. Maximal electromechanical delay (EMDmax), and the maximal rate of muscle activation (RMAmax) of quadriceps muscles were determined. No significant effect of instruction was observed on Fmax (p > 0.05). The RFDmax and RMAmax were significantly higher with the “fast” compared to the “hard-and-fast” instruction (36.07%, ES = 1.99 and 37.24%, ES = 0.92, respectively), whereas EMDmax was significantly lower with the “fast” instruction compared to the “hard-and-fast” instruction (-3.79%, ES = - 0.29). No significant differences between test and retest measurements were found (p < 0.05). However, the reliability of the RFDmax was higher with the fast instruction compared to the hard-and-fast instruction (CV: 7.3 vs. 16.2%; ICC: 0.84 vs. 0.56). Besides, the RFDmax was associated with the RMAmax and EMDmax with a significant effect of instruction. Data showed that the instruction given prior contracting muscle affected explosive force production and associated neuromuscular variables. As a result, the “fast” instruction may be preferred in the assessment of explosive force capacity of skeletal muscle during maximal efforts.

Key words

  • maximal force
  • force development
  • electromyography
  • neuromuscular performance
Otwarty dostęp

Acute Effects of Barefoot And Minimalist Footwear on Medial Tibiofemoral Compartment Loading During Running: A Statistical Parametric Mapping Approach

Data publikacji: 31 Dec 2018
Zakres stron: 35 - 44

Abstrakt

Abstract

The current investigation examined the effects of running barefoot and in minimalist footwear on medial tibiofemoral compartment loading, compared to conventional running trainers. Fifteen male runners ran over a force platform in five different footwear conditions (barefoot, Vibram five-fingers (Footwear A), Inov-8 (Footwear B) Nike-Free (Footwear C), and running trainer) whilst lower extremity kinematics were examined using a three-dimensional camera system. Medial compartment loading during the stance phase was explored using the knee adduction moment (KAM). In addition, the KAM instantaneous load rate was also calculated. Differences between footwear across the entire stance phase were examined using 1-dimensional statistical parametric mapping, whereas differences in discrete parameters were explored using one-way repeated measures ANOVA. Statistical parametric mapping revealed that Footwear B was associated with a significantly larger KAM compared to the running trainer from 15-20 and 25-30% of the stance phase and also Footwear C from 15-20% of the stance phase. The KAM instantaneous load rate was significantly larger in the barefoot (210.69 Nm/kg/s), Footwear A (200.23 Nm/kg/s) and Footwear B (186.03 Nm/kg/s) conditions in comparison to Footwear C (100.88 Nm/kg/s) and running trainers (92.70 Nm/kg/s). The findings from this study indicate that running barefoot and in minimalist footwear with the least midsole interface may place runners at increased risk of medial compartment knee OA, although further exploration using habitual barefoot / minimalist footwear users is required.

Key words

  • biomechanics
  • footwear
  • running
  • knee
  • overuse injury
Otwarty dostęp

A Video-Based Method to Quantify Stroke Synchronisation in Crew Boat Sprint Kayaking

Data publikacji: 31 Dec 2018
Zakres stron: 45 - 56

Abstrakt

Abstract

The study aimed to quantify stroke synchronisation in two-seater crew boat sprint kayaking (K2) using a video-based method, and to assess the intra- and inter-rater reliabilities of this method. Twelve sub-elite sprint kayakers (six males and six females) from a national team were paired into six single-gender K2 crews. The crews were recorded at 120 Hz with a sagittal-view video camera during 200-m time trials. Video analysis identified four meaningful positions of a stroke (catch, immersion, extraction and release). The timing difference (termed “offset”) between the front and back paddlers, within each K2, at each stroke position was calculated, with zero offset indicating perfect synchronisation. Results showed almost perfect intra-rater reliability of this method. The intra-class correlation (ICC) ranged from .87 to 1.00, and standard error of measurement ( SEM) from 0 to 5 milliseconds (ms). Inter-rater reliability was substantial to almost perfect (ICC .72 – .94, SEM 2 – 6 ms). On average, 35 strokes were analysed for each crew and the mean offset was 17 ms, or 5.7% of water phase duration. Crews were more synchronised at the catch (11 ms, 3.8%) than the release (21 ms, 7.2%). However, the stroke synchronisation profiles of the six sub-elite crews varied considerably from each other. For example, the best performing male and female crews had directly contrasting profiles. This suggests that there is no universal stroke synchronisation profile for well-trained sprint kayakers. This video-based method may aid future investigations on improving performance.

Key words

  • paddling
  • team-boat
  • technique
  • performance
  • reliability

Section II - Exercise Physiology & Sports Medicine

Otwarty dostęp

Maximizing the Functional Performance Outcomes of Patients Undergoing Rehabilitation by Maximizing their Overall Health and Wellbeing

Data publikacji: 31 Dec 2018
Zakres stron: 57 - 68

Abstrakt

Abstract

To maximize the performance of an athlete, a team of experts work together to ensure each athlete achieves the maximal benefit from their prescribed exercise conditioning programs. In addition to the exercise specialists, the athlete’s team frequently includes psychologists (who address performance anxiety, stress, and depression), counselors (who address smoking cessation, reduction or elimination of alcohol consumption if necessary, weight optimization, and optimal sleep), and nutritionists (who address optimal nutrition and body mass attributes). Such a collaborative approach has become standard practice for athletes aiming to excel in their sports. Despite unequivocal and compelling evidence, this paradigm has only weakly been transferred to the needs of patients participating in rehabilitation programs. These individuals, like the athlete, also need to achieve their highest level of functional performance and recovery for carrying out their activities of daily living, managing the needs of their families, and often returning to work. This article reviews the evidence-based literature and the implications of this multifaceted approach in rehabilitation programs. The augmented benefits to exercise training and conditioning (prescriptive activity/exercise and less sitting) along with their ‘effect sizes’ are described in the rehabilitation context, in conjunction with smoking cessation, reduced harmful alcohol consumption, optimal nutrition, optimal body mass, manageable stress, and optimal sleep. These factors can be viewed as physical performance enhancers both in individuals participating in rehabilitation whose aim is maximal performance and recovery and in athletes aiming for maximal performance in their sports. Thus, without targeted attention to these lifestyle factors, rehabilitation outcomes cannot be maximized. The evidence presented in this article has implications for health professionals including physical therapists and others who are practicing in rehabilitation settings and those working with individuals in need in the community.

Key words

  • athletes
  • healthy lifestyle practices
  • physical performance
  • International Classification of Function
  • Disability and Health
  • Behavioral Risk Factor Surveillance System
Otwarty dostęp

Post‐Activation Potentiation Increases Recruitment of Fast Twitch Fibers: A Potential Practical Application in Runners

Data publikacji: 31 Dec 2018
Zakres stron: 69 - 78

Abstrakt

Abstract

To determine the relationship between fatigue and post-activation potentiation, we examined the effects of sub-maximal continuous running on neuromuscular function tests, as well as on the squat jump and counter movement jump in endurance athletes. The height of the squat jump and counter movement jump and the estimate of the fast twitch fiber recruiting capabilities were assessed in seven male middle distance runners before and after 40 min of continuous running at an intensity corresponding to the individual lactate threshold. The same test was then repeated after three weeks of specific aerobic training. Since the three variables were strongly correlated, only the estimate of the fast twitch fiber was considered for the results. The subjects showed a significant improvement in the fast twitch fiber recruitment percentage after the 40 min run. Our data show that submaximal physical exercise determined a change in fast twitch muscle fiber recruitment patterns observed when subjects performed vertical jumps; however, this recruitment capacity was proportional to the subjects’ individual fast twitch muscle fiber profiles measured before the 40 min run. The results of the jump tests did not change significantly after the three-week training period. These results suggest that pre-fatigue methods, through sub-maximal exercises, could be used to take advantage of explosive capacity in middle-distance runners.

Key words

  • squat jump
  • middle distance running
  • lactate threshold
  • fibers
  • recruitment
Otwarty dostęp

Pulmonary Rehabilitation with a Stabilometric Platform After Thoracic Surgery: A Preliminary Report

Data publikacji: 31 Dec 2018
Zakres stron: 79 - 87

Abstrakt

Abstract

The aim of this study was to evaluate the influence of exercises on a stabilometric platform on the physical fitness and mobility of patients with lung cancer after thoracic surgery. The Experimental Group included 22, and the Control Group consisted of 21 patients. All included patients were enrolled after thoracic surgery due to lung cancer. The Experimental and Control Groups were enrolled in a 3-week in-hospital pulmonary rehabilitation program. The Experimental Group additionally performed daily 20-min training sessions on a stabilometric platform. Agility and flexibility were assessed with the Fullerton test before and after rehabilitation in both groups, and quality of life was assessed with the SF-36 questionnaire. Exercise performance stated as a distance in a 6 min walking test (6MWT) significantly improved in both groups with a medium effect size. The results of the Fullerton test indicated improvements in flexibility in both groups after the completion of the program without a significant difference between the groups and with a small effect size. In the Experimental Group, the best results were observed in the Arm curl (p = 0.0001), Chair stand (p = 0.04), Up and go (p = 0.001) and Chair sit and reach (p = 0.0001) tasks. No deterioration in the quality of life was observed in the Experimental or the Control Group after the completion of the program. Between-group analyses revealed significant differences in the Role-Physical (RP) (p = 0.020) and Mental-Health (MH) (p = 0.025) domains of the SF-36. The rehabilitation program with a stabilometric platform improved agility and flexibility of patients after thoracic surgery without an effect size or significant differences between the Experimental and Control Groups.

Key words

  • pulmonary
  • rehabilitation
  • lung cancer
  • physical fitness
  • stabilometric platform
Otwarty dostęp

Does Sodium Citrate Cause the Same Ergogenic Effect as Sodium Bicarbonate on Swimming Performance?

Data publikacji: 31 Dec 2018
Zakres stron: 89 - 98

Abstrakt

Abstract

The aim of this study was to investigate the effect of ingesting sodium bicarbonate (SB) and sodium citrate (SC) on 400 m high-intensity swimming performance and blood responses. Six nationally ranked male swimmers (20.7 ± 2.1 yrs; 184 ± 6 cm; 79.9 ± 3.9 kg; 10.6 ± 1% body fat) participated in a double blinded, placebo controlled crossover trial. Ninety minutes after consuming SB (0.3 g·kg-1), SC (0.3 g·kg-1) or a placebo (PL) participants completed a single 400-m freestyle maximal test on three consecutive days. The order of the supplementation was randomized. Capillary blood samples were collected on 4 occasions: at rest (baseline), 60 min post-ingestion, immediately post-trial and 15 min post-trial. Blood pH, HCO3- concentration and base excess (BE) were determined. Blood pH, HCO3-, BE were significantly elevated from before loading to the pre-test (60 min post-ingestion) (p < 0.05) after SB ingestion, but not after SC ingestion (p > 0.05). Performance times were improved by 0.6% (p > 0.05) after supplementation of SB over PL in 5 out of 6 participants (responders). In contrast, ingestion of SC decreased performance by 0.2% (p > 0.05). No side effects were observed in either trial. Delayed blood response was observed after SC ingestion compared to SB and this provided no or modest ergogenic effect, respectively, for single bout high-intensity swimming exercise. Monitoring the magnitude of the time-to-peak level rise in alkalosis may be recommended in order to individualize the loading time accordingly before commencement of exercise.

Key words

  • dietary supplements
  • ergogenic aid
  • performance
  • nutrition
Otwarty dostęp

Differences in Loading and Morphological Structure of the Take‐off and Non‐take‐off Limb in Athletics Jumping Events

Data publikacji: 31 Dec 2018
Zakres stron: 99 - 109

Abstrakt

Abstract

The objective of the study was to assess differences between the take-off and non-take-off limbs of athletes in track-and-field jumping events based on a segmental analysis of body composition as well as kinetic analysis. The research included 19 participants (10 males, 9 females) with an average age of 18.1 ± 2.8 years. We measured body height, body mass, body composition (body fat, fat free mass, bone mineral content and bone density) and segmental distribution of these variables. To assess strength of the lower limbs, we performed reaction force analysis during take-off and run symmetry. The difference in the representation of soft tissues between the take-off and non-take-off limbs was not significant; the differences were 0.06%, 0 kg in body fat and 0.01 kg in fat free mass. The differences in the values of bone matter were significant. The bone mineral content was 0.05 kg higher in the take-off limb (p < 0.001), and bone density was 0.07 g/cm2 higher (p < 0.001); the practical significance of the difference was intermediate (d = 0.5). Kinetic analysis showed that athletes exerted greater force on the pad with the take-off limb than the non-take-off limb when taking off while using arms in the first peak of the vertical force. The difference determined in this type of take-off was statistically significant (p < 0.05); the practical significance of the difference was medium (d = 0.7). The difference in the second peak of the vertical reaction force in the take-off arm was not statistically significant. The differences were reflected in the different bone matter compositions.

Key words

  • kinetics
  • body composition
  • segmental analysis
  • take-off limb
Otwarty dostęp

The Effect of Physical And Mental Stress on the Heart Rate, Cortisol and Lactate Concentrations in Rock Climbers

Data publikacji: 31 Dec 2018
Zakres stron: 111 - 123

Abstrakt

Abstract

Rock climbing is a physical activity that not only causes an increase in muscle tension, heart rate and blood pressure, but also results in the elevation of stress hormones including cortisol. It has not been established which of the above mentioned variables serve as the most accurate indicator of rock climbing-induced physical and mental stress. The aim of this study was to evaluate the effect of physical activity, short-term fatigue and mental demand on heart rate (HR), salivary cortisol (C) and blood plasma lactate (LA) concentrations in rock climbers under laboratory conditions. Twelve male and female rock climbers of comparable climbing performance (5a – 6b OS) were recruited. The participants completed two routes of different climbing difficulty (effect of physical demand), repeated a difficult route with a short 5-min recovery period three times (effect of fatigue), and repeated a difficult lead climb (effect of mental demand). Heart rate as well as C and LA concentrations were determined. The results indicated that more difficult climbing routes elicited increases in HR (especially relative values) and LA concentrations, whereas fatigue accumulation had an effect on climbing HR and relative C concentration values. Lead climbing only caused an increase in climbing HR. Based on the results it was concluded that HR was a good indicator of physical and mental stress intensity. Performing the same difficult route three times with a short recovery period in-between turned out to be the most demanding task and resulted in the highest increase of the cortisol concentration. Dynamics of changes in lactate concentrations depend on muscle loading (local muscular effort), lactate clearance and technical/tactical skills of the climber.

Key words

  • workload intensity
  • physiological response
  • rock climbing
Otwarty dostęp

No Modification in Blood Lipoprotein Concentration but Changes in Body Composition After 4 Weeks of Low Carbohydrate Diet (LCD) Followed by 7 Days of Carbohydrate Loading in Basketball Players

Data publikacji: 31 Dec 2018
Zakres stron: 125 - 137

Abstrakt

Abstract

Recently, low carbohydrate diets have become very popular due to their numerous health benefits. Unfortunately, little is known about their chronic effects on the blood lipid profile and other cardiovascular disease risk factors in athletic populations. We compared the results of a four week, well-planned low carbohydrate diet (LCD) followed by seven days of carbohydrate loading (Carbo-L) on fasting lipids - triacylglycerol’s (TAG), LDL-C, HDL-C, total cholesterol (TCh), glucose, insulin and HOMA-IR levels in 11 competitive basketball players. During the experiment, we also measured body mass (BM) and body composition changes: body fat (BF), % of body fat (PBF), and fat free mass (FFM). Both diet procedures significantly changed the fasting serum concentration of TAG (p < 0.05) and body fat content (kg and %) (p < 0.05), without negative changes in FFM. The Carbo-L procedure increased (p < 0.05) fasting glucose levels significantly. A LCD may be suggested for athletes who want to reduce body mass and fat content without compromising muscle mass. Several weeks on a LCD does not change the lipoprotein - LDL-C and HDL-C level significantly, while a seven-day Carb-L procedure may increase body fat content and fasting glucose concentration. Such dietary procedures are recommended for team sport athletes to reduce fat mass, lipid profile disorders and insulin resistance.

Key words

  • nutrition
  • competitive athletes
  • lipoprotein profile
  • body mass
  • fat content
  • carbo loading
Otwarty dostęp

Salivary BDNF and Cortisol Responses During High‐Intensity Exercise and Official Basketball Matches in Sedentary Individuals and Elite Players

Data publikacji: 31 Dec 2018
Zakres stron: 139 - 149

Abstrakt

Abstract

Salivary cortisol increases in response to stressors, including physical exertion and psychological stress associated with sports competition. In addition, stress may induce change in brain-derived neurotrophic factor (BDNF). However, there are still no data available to compare the salivary BDNF level in sedentary male individuals and elite team-sport male athletes, regularly involved in activities that require elevated attention and concentration. This information could contribute to the advance of understanding of the effect of regular exercise on the salivary level of BDNF, the pre-to-post change in salivary BDNF during exercise, and the association between salivary cortisol and salivary BDNF responses to physical exercise. Therefore, this study aimed to compare the concentration of salivary cortisol and BDNF, before and after exercise, in sedentary individuals and elite male basketball players. The sedentary group (23.0 ± 4.2 yrs) performed a high-intensity exercise protocol and the basketball players (18.6 ± 0.5 yrs) participated in three official basketball matches. Saliva samples were tested for cortisol and BDNF using ELISA. A significant increase in salivary cortisol from pre- to post-match was observed only for the basketball players (p < 0.05). Basketball players also presented a higher salivary BDNF concentration for both resting (pre) and post-physical exercise (p < 0.05); however, no change in pre- to post-exercise salivary BDNF was observed for either group (p > 0.05). Elevated BDNF in athletes may be associated to their repeated exposure to stressful competition situations. The current findings also suggest that different mechanisms might be involved in salivary cortisol and BDNF responses during physical exercise.

Key words

  • saliva
  • team-sports
  • stress
  • athletes
  • neuroendocrinology
  • exercise
Otwarty dostęp

Exercise‐Based Cardiac Rehabilitation with and without Neuromuscular Electrical Stimulation and its Effect on Exercise Tolerance and Life Quality of Persons with Chronic Heart Failure

Data publikacji: 31 Dec 2018
Zakres stron: 151 - 164

Abstrakt

Abstract

The study compares the effect of an exercise-based cardiac rehabilitation program with a program combining physical exercise and lower extremity neuromuscular electrical stimulation (NMES) on the recovery of patients with chronic heart failure (CHF) with NYHA II-III symptoms. Seventy two patients with stable CHF were randomly distributed to four groups that received exercise-based cardiac rehabilitation and pharmacological treatment. Groups I and II were additionally administered NMES (35 Hz and 10 Hz, respectively) and in Group III sham NMES was applied. Group IV (controls) received solely pharmacological and exercise treatment. Exercise tolerance and quality of life were assessed in patients pre-treatment and at week 3. Three weeks of rehabilitation induced significant increases (p < 0.05) in the distance covered in the 6-minute walk test, the metabolic equivalent (MET), the duration of the treadmill exercise stress test, the left ventricle ejection fraction (LVEF) and improved quality of life in all groups, but between-group differences were not significant (p > 0.05). In none of the groups were the left ventricle end-systolic and end-diastolic diameters (mm) measured at week 3 significantly different from their baseline values (p > 0.05). Exercise-based cardiac rehabilitation contributed to higher exercise tolerance, LVEF and quality of life of CHF patients (NYHA II-III), contrary to cardiac rehabilitation combined with lower extremity NMES (35 Hz and 10 Hz) that failed to induce such improvements. More research is necessary to assess the therapeutic efficacy of NMES applied to CHF patients with NYHA IV symptoms.

Key words

  • physical activity
  • cardiac rehabilitation
  • chronic heart failure
  • neuromuscular electrical stimulation
  • exercise tolerance
  • quality of life

Section III - Sports Training

Otwarty dostęp

Work-rate Analysis of Substitute Players in Professional Soccer: Analysis of Seasonal Variations

Data publikacji: 31 Dec 2018
Zakres stron: 165 - 174

Abstrakt

Abstract

The aims of this study were to evaluate physical performance of substitute players versus those replaced or completing the entire match, determine physical performance of substitute players across different playing positions and examine variations in match-related running performance in substitute players throughout the entire competitive season. The sample was composed of 943 observations of professional players who participated in the first division of the Spanish League (La Liga) during the 2014-2015 season. The players were divided into three different groups: players who completed the entire match (n = 519), players who were replaced (n = 212) and substitute players (n = 212). Substitute players covered greater distances at medium and high intensity compared to the players who played the entire match and those who were replaced. Position-specific trends indicated that attackers and central midfielder increased the distance covered at high-intensity running compared to their peers who played the whole match. During the competitive season, it was observed that substitute players attained greater match running performance during the mid-season period, allowing them to cover more distance for different variables of running performance compared to the start and end of the season.

Key words

  • substitute's performance analysis
  • seasonal variations
  • playing position
  • high-intensity running
Otwarty dostęp

Effects of the Pitch Surface on Displacement of Youth Players During Soccer Match-Play

Data publikacji: 31 Dec 2018
Zakres stron: 175 - 185

Abstrakt

Abstract

The aim of this study was to analyze the effect of different pitch surfaces (artificial turf, natural turf and dirt field) on positioning and displacement of young soccer players (age: 13.4 ± 0.5 yrs; body height: 161.82 ± 7.52 cm; body mass: 50.79 ± 7.22 kg and playing experience: 3.5 ± 1.4 yrs). Data were collected using GPS units which allowed to calculate spatial distribution variability, assessed by measuring entropy of individual distribution maps (ShannEn). Ellipsoidal areas (m2) representing players’ displacement on the pitch, centred on the average players’ positional coordinates, were also calculated, with axes corresponding to the standard deviations of the displacement in the longitudinal and lateral directions. Analysis of variance (ANOVA) was used to evaluate differences between pitch surfaces and across players’ positions. There was significant effect in positioning (η2 = 0.146; p < 0.001) and displacement (η2 = 0.063; p < 0.05) by the players between pitch surfaces. A dirt field condition induced an increase in the players’ movement variability, while players’ displacement was more restricted when playing on artificial turf. Also, there were significant effects on positioning (η2 = 0.496; p < 0.001) and displacement (η2 = 0.339; p < 0.001) across players’ positions. Central midfielders presented the greatest movement variability and displacement while fullbacks showed the lowest variability. Subsequently, the results may contribute to implement strategies that optimise players’ performance in different surface conditions.

Key words

  • movement variability
  • spatial distribution maps
  • performance analysis
  • entropy
  • tactical demands
Otwarty dostęp

Effect of Different Feedback Modalities on Swimming Pace: Which Feedback Modality is Most Effective?

Data publikacji: 31 Dec 2018
Zakres stron: 187 - 195

Abstrakt

Abstract

To compare the effect of three different feedback modalities on swimming pace, sixteen male swimmers and triathletes participated in this study. Each participant swam 3 x 400 m, one for each feedback modality, swimming front crawl at 80% of their individual swimming critical speed. Three feedback modalities were examined: self-pacing, real time visual feedback and real time voice feedback. The swimmers adopted a fast start in all feedback modalities. In the real time voice feedback modality, the data recorded during the second lap (200 m) showed a significant improvement of their swimming pace approaching the swimming pace intended (-1.47 s, p < .01, medium effect size 0.79). A significant improvement toward the swimming pace intended was also noticed at the third split time (300 m) (0.05 s, p < .01, large effect size 0.81) and at the fourth split time (400 m) (0.46 s, p < .01, medium effect size 0.76). In self-pacing, the swimmers were not able to swim in line with the swimming pace intended. In real time visual feedback modality, the swimmers did not show a significant improvement approaching the swimming pace intended. The results revealed that communication with the swimmers using the real time voice feedback induced a significant improvement in their swimming pace and could help the athletes to swim with accurate and consistent pace.

Key words

  • training
  • performance
  • auditory pathways
  • sensory
  • split time
Otwarty dostęp

Relative Age Effect and Long-Term Success in the Spanish Soccer and Basketball National Teams

Data publikacji: 31 Dec 2018
Zakres stron: 197 - 204

Abstrakt

Abstract

The aims of this study were: i) to analyze whether relative age effect occurs in the athletes of the junior national teams and professional athletes in Spain in general and in soccer and basketball, and ii) to compare the long-term success of the players selected for the junior national team between these sports. The samples for this study were Spanish professional soccer (n = 461) and basketball (n = 250) players in the 2013-2014 premier league and players from the junior Spanish soccer (i.e., n = 273; U-17: n = 107; U-19: n = 166) and basketball (i.e., n = 240; U-18: n = 120, U-16: n = 120) teams that classified to play in the European Championships (from 2004 to 2013). Junior players (42.3%) were more frequently born in the 1st quarter of the year than the professional players (30.7%) (χ2(3) = 30.07; p = .001; Vc = .157). This was found in both basketball (χ2(3) = 12.2.; p = .007; Vc = .158) and soccer (χ2(3) = 20.13; p < .001; Vc = .166). Long-term success is more frequent in soccer, where 59.9% of the juniors selected for the national team played later in the premier league, while in basketball that percentage was 39.6% (χ2(1) = 14.64; p < .001; Vc = .201). On the other hand, 79.4% and 39.8% of the professional soccer and basketball players had been previously selected for junior national teams (χ2(1) = 60.2; p < .001; Vc = .386), respectively. The talent selection process should be reviewed as players born in the second half of the year have fewer opportunities to stand out.

Key words

  • talent
  • selection
  • performance
  • soccer
  • basketball
Otwarty dostęp

Intra and Interzone Differences of Attack and Counterattack Efficiency in Elite Male Volleyball

Data publikacji: 31 Dec 2018
Zakres stron: 205 - 212

Abstrakt

Abstract

The primary goal of this study was to identify and explain differences in a volleyball set between winning and defeated teams, based on frequency and efficiency of the attack and counterattack, both overall and from particular zones of the volleyball court. Research was conducted on a randomly chosen sample of 206 sets played in 55 matches of the Men's Champions League. A total of 10555 spikes in the attack and counterattack from various zones of the volleyball court were analyzed. Between-subjects 2×5 factorial ANOVA (Outcome×Zone) was used to identify significant differences between the set outcome and zones or their interaction for both attack and counterattack efficiency. Significant differences were found in the efficiency of spikes in attacks and counterattacks from various zones of the volleyball court and between winning and losing teams. Post-hoc analysis of interaction effects also revealed significant differences. The obtained results substantiate the importance of spiking, both in the attack and counterattack, for winning a volleyball set, and indicate the specific values of spiking in the attack and counterattack from various zones, for both winning and defeated teams. The results of this study can be useful for coaches, in evaluation of player's performance in the match, in planning and programming the training process as well as in the technical and tactical preparation of the team for the tournament.

Key words

  • notational analysis
  • spiking
  • performance quality
  • factorial ANOVA
Otwarty dostęp

Effects of Core Strength Training Using Stable and Unstable Surfaces on Physical Fitness and Functional Performance in Professional Female Futsal Players

Data publikacji: 31 Dec 2018
Zakres stron: 213 - 224

Abstrakt

Abstract

The aim of this study was to assess the effect of core strength training performed on a stable surface (CTS) compared with core strength training performed on an unstable surface (CTU) on physical fitness (jump performance, sprint, and repeated sprint ability (RSA)) and quality of movement (Fundamental Movement Screen) in professional female futsal players. Fourteen professional female futsal players (mean age: 23.7 ± 5.1 years, age range: 18-28 years) were randomly assigned to a CTS (n = 7) or a CTU (n = 7) group. The intervention program was carried out 3 times a week over 6 weeks. Players of both groups performed the same four core-strengthening exercises. The only difference between the two interventions was that the CTU group performed all exercises (i.e., shoulder bridge, side bridge, prone plank, and crunch) on an unstable surface (Togu® Dyn-Air). Within-group analysis showed significant improvements (p < 0.001) in 10 m sprint performance from the pre- to post-test in the CTS (+4.37%) and CTU (+5.00%) groups. Players in both the CTS (+10.39%) and CTU (+11.10%) group also showed significant enhancement in the Functional Movement Screen total score, from the pre-test to post-test. In addition, a significant time effect was also observed for the CTU group in the relative score of the RSA test decreasing from the pre- to post-test (-30.85%). In the between-groups analysis, there were no significant differences between the core strength training groups (CTS vs CTU) in any variable. To conclude, sprint and Functional Movement Screen performance improved following CTS and CTU when conducted in combination with regular futsal training. In addition, CTU had limited benefit in RSA compared to CTS.

Key words

  • resistance training
  • trunk stability
  • Functional Movement Screen
  • explosive strength
  • repeated sprint ability
Otwarty dostęp

Basketball Game-Related Statistics that Discriminate Between European Players Competing in the NBA and in the Euroleague

Data publikacji: 31 Dec 2018
Zakres stron: 225 - 233

Abstrakt

Abstract

This study aimed to identify the game-related statistics that discriminated between Euroleague basketball players and European basketball players playing in the NBA, when competing in the same event (EuroBasket 2015). There was a total of 78 matches played by 24 teams in two groups of analysis: NBA, participants in the European Championship who played in the NBA season of 2014-2015 (n = 26); Euroleague, participants in the European Championship who played in the Euroleague season of 2014-2015 (n = 82). The players’ performance variables were normalized to the time they spent on the court. To identify which variables best discriminated between the NBA and the Euroleague performance profiles, a descriptive discriminant analysis was conducted. Structure coefficients (SC) from the matrix greater than |0.30| were interpreted as meaningful contributors to discriminating between the groups. The results revealed a significant function (p = 0.008, canonical correlation of 0.51, Λ = 0.74, reclassification = 84.2%) and substantial performance differences in game-related statistics much related to the influence of body size (body height and mass), such as two-point field goals made (SC = 0.42) and missed (SC = 0.40), free-throws made (SC = 0.55), defensive rebounds (SC = 0.62), blocks (SC = 0.48) and suffered fouls (SC = 0.34). No differences were found at the level of game-related statistics indirectly related to perception, such as assists, turnovers or steals. Also, the greater body size in NBA players was likely related to higher variability in performance, thus, being an important topic for coaches and recruiters to analyse.

Key words

  • performance profile
  • analysis
  • game-related statistics
  • discriminant scores
Otwarty dostęp

Training Loads and RSA and Aerobic Performance Changes During the Preseason in Youth Soccer Squads

Data publikacji: 31 Dec 2018
Zakres stron: 235 - 248

Abstrakt

Abstract

The aims of this study were to compare the internal training load (ITL) in soccer players of two competitive age groups (under-15 [U-15] and under-19 [U-19]) during an 8-week preseason training period and compare the associated changes in physical performance measures. Eighteen U-15 and twelve U-19 players were monitored over an 8-week period during the preseason phase. The ITL was monitored using the session rating of perceived exertion (RPE) method. Before and after the preseason period, physical performance was assessed by best (RSAbest) and mean (RSAmean) times in a repeated sprint ability (RSA) test and peak velocity derived from the Carminatti test (PVT-CAR). Total weekly ITL increased with age (U-15: 13770 ± 874 AU vs. U-19: 33584 ± 2506 AU; p < 0.001). In addition, U-19 players perceived training sessions as heavier than U-15 players (6.1 ± 0.3 vs. 5.3 ± 0.3 AU, respectively; p < 0.001). After the preseason period, very likely to almost certainly positive changes were observed for all performance measures in both age groups. However, the U-15 group had possibly superior gains in RSAbest (+1.40%, 90%CL -0.29 to 3.05, with ES = 0.35) and likely higher effects in RSAmean (+1.89%, 90%CL 0.04 to 3.70, with ES = 0.53) and PVT-CAR (+2.71%, 90%CL 0.35 to 5.01, with ES = 0.37) compared to the U-19 group. In conclusion, our findings demonstrate that the U-19 group accumulate higher total weekly ITLs than the U-15 group during the preseason phase due to longer and heavier training sessions. However, the U-15 group obtained superior gains in soccer-specific physical abilities while accumulating half the total ITLs during lighter training sessions.

Key words

  • field testing
  • physical adaptation
  • rating of perceived exertion
  • team sports
  • youth athletes
Otwarty dostęp

Technical and Training Related Aspects of Resistance Training Using Blood Flow Restriction in Competitive Sport - A Review

Data publikacji: 31 Dec 2018
Zakres stron: 249 - 260

Abstrakt

Abstract

Blood flow restriction (BFR) combined with resistance training (RT-BFR) shows significant benefits in terms of muscle strength and hypertrophy. Such effects have been observed in clinical populations, in groups of physically active people, and among competitive athletes. These effects are comparable or, in some cases, even more efficient compared to conventional resistance training (CRT). RT-BFR stimulates muscle hypertrophy and improves muscle strength even at low external loads. Since no extensive scientific research has been done in relation to groups of athletes, the aim of the present study was to identify technical, physiological and methodological aspects related to the use of RT-BFR in competitive athletes from various sport disciplines. RT-BFR in groups of athletes has an effect not only on the improvement of muscle strength or muscle hypertrophy, but also on specific motor abilities related to a particular sport discipline. The literature review reveals that most experts do not recommend the use RT-BFR as the only training method, but rather as a complementary method to CRT. It is likely that optimal muscle adaptive changes can be induced by a combination of CRT and RT-BFR. Some research has confirmed benefits of using CRT followed by RT-BFR during a training session. The use of BFR in training also requires adequate progression or modifications in the duration of occlusion in a training session, the ratio of exercises performed with BFR to conventional exercises, the value of pressure or the cuff width.

Key words

  • occlusion
  • resistance exercise
  • training variables
  • sports performance

Section IV - Behavioural Sciences in Sport

Otwarty dostęp

Cognitive Scripts, Anxiety and Styles of Coping with Stress in Teenagers Practising Sports

Data publikacji: 31 Dec 2018
Zakres stron: 261 - 271

Abstrakt

Abstract

The aim of the study was to present the relationships between the way of perceiving oneself and the world by young athletes, the cognitive anxiety and the ways of coping with stress. The target group consisted of 222 participants (114 boys and 108 girls) aged 16–20, students of sports-profiled secondary schools. The participants specialised in both winter and summer sports, as well as in individual and team sport disciplines. The following tools were implemented: Attitudes to Intrapersonal, Interpersonal and to the World Questionnaire, Coping Inventory for Stressful Situations (CISS) and Sport Anxiety Scale. The study showed that negative perception of oneself and others increases the level of cognitive anxiety and decreases the tendencies to search for social contacts in the face of stress. With regard to the positive image of oneself and others, the opposite was observed. The above relationships refer mainly to girls who practise sports.

Key words

  • image
  • image of the world
  • coping with stress
  • cognitive and somatic anxiety
  • youth
  • sport
Otwarty dostęp

Moral Behavior in the Locker Room Predicts Perceptions of Task Cohesion in Youth Ice Hockey Player

Data publikacji: 31 Dec 2018
Zakres stron: 273 - 280

Abstrakt

Abstract

Task cohesion (i.e., perceptions of team unity towards a task goal and positive feelings towards one’s own involvement) is associated with myriad psychosocial benefits for youth athletes. Accordingly, sport researchers and youth sport stakeholders are interested in ways of fostering task cohesion. Recent work has found evidence that prosocial and antisocial behaviors among teammates are associated with athletes’ perceptions of task cohesion; however, this research has been limited to moral behavior that takes place during gameplay. Despite youth sport experiences extending well beyond practices and games, we know very little about how moral behavior between teammates, in settings outside gameplay, relates to perceptions of task cohesion. To address this knowledge gap, the current study investigated whether prosocial and antisocial behaviors in the locker room setting were associated with perceptions of task cohesion in a sample of 238 youth male ice hockey players (Mage = 10.75). Using hierarchical regression analyses, our results revealed that (a) perceptions of peer prosocial behavior was positively associated with task cohesion, (b) perceptions of peer antisocial behavior was negatively associated with task cohesion, and (c) self-reported perceptions of participants’ own moral behavior was not significantly associated with task cohesion. Given the association with perceptions of task cohesion, these findings underline the value in promoting prosocial behavior and reducing antisocial behavior in sport settings outside gameplay and hold multiple theoretical and practical implications. Notably, moral behavior that takes place outside gameplay settings may be related to perceptions of task cohesion that primarily relates to goals and interactions during gameplay.

Key words

  • youth sport
  • group dynamics
  • prosocial behavior
  • antisocial behavior
  • adult supervision
Otwarty dostęp

Relations Among Reinvestment, Self-Regulation, and Perception of Choking Under Pressure

Data publikacji: 31 Dec 2018
Zakres stron: 281 - 290

Abstrakt

Abstract

The purpose of this study was to examine relations among reinvestment, self-regulation, and perception of choking under pressure in skilled tennis players. Participants were 160 collegiate players from the NCAA Division I in the U.S. and the 1st League in Japan. Participants completed questionnaires assessing reinvestment (conscious motor processing and movement self-consciousness), self-regulation, and perception of choking under pressure. Results of correlation analysis indicated self-regulatory factors were positively related to reinvestment conscious motor processing, but not with reinvestment movement self-consciousness. Self-efficacy and movement self-consciousness of reinvestment were found to predict one’s perception of choking under pressure. Results of simultaneous entry multiple regression revealed that tennis players who had low self-efficacy and were concerned about making a good impression with their movements were more likely to perceive that they choked during tennis matches. Additionally, Japanese players reported less self-regulation skills and a higher perception of choking under pressure than American players, suggesting the need for additional research on cross-cultural differences. Overall, these results suggest that self-efficacy may protect athletes from choking, but movement self-consciousness may lead athletes to choke during tennis games.

Key words

  • self-focus
  • metacognition
  • self-efficacy
  • collegiate athletes
  • cross-cultural comparison
Otwarty dostęp

The mediation effect of Perceived Social Support and Perceived Stress on the relationship between Emotional Intelligence and Psychological Wellbeing in Male Athletes

Data publikacji: 31 Dec 2018
Zakres stron: 291 - 303

Abstrakt

Abstract

This study aimed to examine the relationship between emotional intelligence (EI) and psychological wellbeing in a three-month follow-up study of male athletes. In addition, we examined the mediating role of perceived social support and perceived stress on the relationship between EI and psychological wellbeing. The sample included 398 male athletes who completed measures of emotional intelligence (Schutte Self-Report Inventory), psychological wellbeing (Ryff Psychological Wellbeing Scale; SSRI), perceived social support (Multidimensional Scale of Perceived Social Support), and perceived stress (Perceived Stress Scale–10). Results from structural equation modelling procedures identified that perceived social support and perceived stress partially mediated the association between EI and psychological wellbeing. The sequential mediation effects of perceived social support–perceived stress on the relations between EI and wellbeing were confirmed. Finally, limitations and recommendations for future research were considered

Key words

  • emotional intelligence
  • psychological wellbeing
  • perceived social support
  • perceived stress
  • athletes
27 Artykułów

Section I - Kinesiology

Otwarty dostęp

Test-Retest Reliability of Isokinetic Arm Strength Measurements in Competitive Swimmers

Data publikacji: 31 Dec 2018
Zakres stron: 5 - 11

Abstrakt

Abstract

Swimming motor patterns lead internal rotators to grow stronger than antagonist muscles, what may increase the risk of injury in swimmers. Injury prevention often involves the improvement of external rotators strength, as well as the external rotation/internal rotation ratio. The current research aimed to evaluate the test-retest reliability of shoulder concentric rotation strength in competitive swimmers using an isokinetic dynamometer. The study enrolled 35 competitive swimmers aged between 13 and 19 years. Concentric movements were performed including internal and external rotations of the shoulder joint following the instructions of the standardized protocol. The angular velocity of the test was defined at 60º/s. Outcome measures were peak torque (Nm) and work (J), measured in both, the dominant and non-dominant arms. The external rotation/internal rotation ratio was also calculated. Reliability was excellent for peak torque and work. For the external rotation/internal rotation ratio, the ICC oscillated between 0.744 and 0.860 for the work ratio of the non-dominant arm and the peak torque ratio of the dominant arm, respectively. In general terms, better reliability was observed for peak torque compared with work, for external rotation compared with internal rotation, and for the dominant arm compared with the non-dominant one.

Key words

  • reliability
  • swimming
  • injury prevention
  • sport injuries
  • peak torque
Otwarty dostęp

Neurocognitive Functioning of Sport Climbers

Data publikacji: 31 Dec 2018
Zakres stron: 13 - 19

Abstrakt

Abstract

Sport climbing, included in the programme of the Tokyo 2020 Summer Olympic Games, is increasingly gaining in popularity as a method of physical and mental health enhancement. Studies show a positive relationship between climbing and improvement of neurocognitive functioning. The aim of this study was to determine the differences in neurocognitive indicators: time of testing, memory, and location between climbers and non-climbers. The sample comprised 30 sport climbers (15 males, 15 females; aged 25 ± 4 years) practicing climbing regularly for five years, and 30 non-climbing age- and sex-matched controls. The Tactual Performance Test (Halstead-Reitan Test Battery) was used to measure neurocognitive functions (tactile-spatial functions, motion coordination, kinesthetic abilities, learning, memory). Significant differences were found between sport climbers and controls in reference to time, memory, and location (p < 0.05). Climbers reached higher memory as well as location ratios and lower time ratios in comparison to controls. Different strategies used to complete the task between the two groups were observed. The neurocognitive functioning of sport climbers manifests itself in faster recognition and differentiation of tactile input and better spatial perception, tactile perception, and movement memory.

Key words

  • neurocognitive functioning
  • sport climbing
  • Tactual Performance Test
Otwarty dostęp

The Influence of Verbal Instruction on Measurement Reliability and Explosive Neuromuscular Performance of the Knee Extensors

Data publikacji: 31 Dec 2018
Zakres stron: 21 - 34

Abstrakt

Abstract

The current study aimed to examine the effect of verbal instruction on explosive force production and between-session measurement reliability during maximal voluntary contractions of knee extensors. Following familiarization, 20 healthy males performed 3 maximal contractions with a “hard-and-fast” instruction and 3 maximal contractions with a “fast” instruction during 2 test-retest sessions. Knee extension maximal voluntary force (Fmax) and the maximal rate of force development (RFDmax) were measured. Maximal electromechanical delay (EMDmax), and the maximal rate of muscle activation (RMAmax) of quadriceps muscles were determined. No significant effect of instruction was observed on Fmax (p > 0.05). The RFDmax and RMAmax were significantly higher with the “fast” compared to the “hard-and-fast” instruction (36.07%, ES = 1.99 and 37.24%, ES = 0.92, respectively), whereas EMDmax was significantly lower with the “fast” instruction compared to the “hard-and-fast” instruction (-3.79%, ES = - 0.29). No significant differences between test and retest measurements were found (p < 0.05). However, the reliability of the RFDmax was higher with the fast instruction compared to the hard-and-fast instruction (CV: 7.3 vs. 16.2%; ICC: 0.84 vs. 0.56). Besides, the RFDmax was associated with the RMAmax and EMDmax with a significant effect of instruction. Data showed that the instruction given prior contracting muscle affected explosive force production and associated neuromuscular variables. As a result, the “fast” instruction may be preferred in the assessment of explosive force capacity of skeletal muscle during maximal efforts.

Key words

  • maximal force
  • force development
  • electromyography
  • neuromuscular performance
Otwarty dostęp

Acute Effects of Barefoot And Minimalist Footwear on Medial Tibiofemoral Compartment Loading During Running: A Statistical Parametric Mapping Approach

Data publikacji: 31 Dec 2018
Zakres stron: 35 - 44

Abstrakt

Abstract

The current investigation examined the effects of running barefoot and in minimalist footwear on medial tibiofemoral compartment loading, compared to conventional running trainers. Fifteen male runners ran over a force platform in five different footwear conditions (barefoot, Vibram five-fingers (Footwear A), Inov-8 (Footwear B) Nike-Free (Footwear C), and running trainer) whilst lower extremity kinematics were examined using a three-dimensional camera system. Medial compartment loading during the stance phase was explored using the knee adduction moment (KAM). In addition, the KAM instantaneous load rate was also calculated. Differences between footwear across the entire stance phase were examined using 1-dimensional statistical parametric mapping, whereas differences in discrete parameters were explored using one-way repeated measures ANOVA. Statistical parametric mapping revealed that Footwear B was associated with a significantly larger KAM compared to the running trainer from 15-20 and 25-30% of the stance phase and also Footwear C from 15-20% of the stance phase. The KAM instantaneous load rate was significantly larger in the barefoot (210.69 Nm/kg/s), Footwear A (200.23 Nm/kg/s) and Footwear B (186.03 Nm/kg/s) conditions in comparison to Footwear C (100.88 Nm/kg/s) and running trainers (92.70 Nm/kg/s). The findings from this study indicate that running barefoot and in minimalist footwear with the least midsole interface may place runners at increased risk of medial compartment knee OA, although further exploration using habitual barefoot / minimalist footwear users is required.

Key words

  • biomechanics
  • footwear
  • running
  • knee
  • overuse injury
Otwarty dostęp

A Video-Based Method to Quantify Stroke Synchronisation in Crew Boat Sprint Kayaking

Data publikacji: 31 Dec 2018
Zakres stron: 45 - 56

Abstrakt

Abstract

The study aimed to quantify stroke synchronisation in two-seater crew boat sprint kayaking (K2) using a video-based method, and to assess the intra- and inter-rater reliabilities of this method. Twelve sub-elite sprint kayakers (six males and six females) from a national team were paired into six single-gender K2 crews. The crews were recorded at 120 Hz with a sagittal-view video camera during 200-m time trials. Video analysis identified four meaningful positions of a stroke (catch, immersion, extraction and release). The timing difference (termed “offset”) between the front and back paddlers, within each K2, at each stroke position was calculated, with zero offset indicating perfect synchronisation. Results showed almost perfect intra-rater reliability of this method. The intra-class correlation (ICC) ranged from .87 to 1.00, and standard error of measurement ( SEM) from 0 to 5 milliseconds (ms). Inter-rater reliability was substantial to almost perfect (ICC .72 – .94, SEM 2 – 6 ms). On average, 35 strokes were analysed for each crew and the mean offset was 17 ms, or 5.7% of water phase duration. Crews were more synchronised at the catch (11 ms, 3.8%) than the release (21 ms, 7.2%). However, the stroke synchronisation profiles of the six sub-elite crews varied considerably from each other. For example, the best performing male and female crews had directly contrasting profiles. This suggests that there is no universal stroke synchronisation profile for well-trained sprint kayakers. This video-based method may aid future investigations on improving performance.

Key words

  • paddling
  • team-boat
  • technique
  • performance
  • reliability

Section II - Exercise Physiology & Sports Medicine

Otwarty dostęp

Maximizing the Functional Performance Outcomes of Patients Undergoing Rehabilitation by Maximizing their Overall Health and Wellbeing

Data publikacji: 31 Dec 2018
Zakres stron: 57 - 68

Abstrakt

Abstract

To maximize the performance of an athlete, a team of experts work together to ensure each athlete achieves the maximal benefit from their prescribed exercise conditioning programs. In addition to the exercise specialists, the athlete’s team frequently includes psychologists (who address performance anxiety, stress, and depression), counselors (who address smoking cessation, reduction or elimination of alcohol consumption if necessary, weight optimization, and optimal sleep), and nutritionists (who address optimal nutrition and body mass attributes). Such a collaborative approach has become standard practice for athletes aiming to excel in their sports. Despite unequivocal and compelling evidence, this paradigm has only weakly been transferred to the needs of patients participating in rehabilitation programs. These individuals, like the athlete, also need to achieve their highest level of functional performance and recovery for carrying out their activities of daily living, managing the needs of their families, and often returning to work. This article reviews the evidence-based literature and the implications of this multifaceted approach in rehabilitation programs. The augmented benefits to exercise training and conditioning (prescriptive activity/exercise and less sitting) along with their ‘effect sizes’ are described in the rehabilitation context, in conjunction with smoking cessation, reduced harmful alcohol consumption, optimal nutrition, optimal body mass, manageable stress, and optimal sleep. These factors can be viewed as physical performance enhancers both in individuals participating in rehabilitation whose aim is maximal performance and recovery and in athletes aiming for maximal performance in their sports. Thus, without targeted attention to these lifestyle factors, rehabilitation outcomes cannot be maximized. The evidence presented in this article has implications for health professionals including physical therapists and others who are practicing in rehabilitation settings and those working with individuals in need in the community.

Key words

  • athletes
  • healthy lifestyle practices
  • physical performance
  • International Classification of Function
  • Disability and Health
  • Behavioral Risk Factor Surveillance System
Otwarty dostęp

Post‐Activation Potentiation Increases Recruitment of Fast Twitch Fibers: A Potential Practical Application in Runners

Data publikacji: 31 Dec 2018
Zakres stron: 69 - 78

Abstrakt

Abstract

To determine the relationship between fatigue and post-activation potentiation, we examined the effects of sub-maximal continuous running on neuromuscular function tests, as well as on the squat jump and counter movement jump in endurance athletes. The height of the squat jump and counter movement jump and the estimate of the fast twitch fiber recruiting capabilities were assessed in seven male middle distance runners before and after 40 min of continuous running at an intensity corresponding to the individual lactate threshold. The same test was then repeated after three weeks of specific aerobic training. Since the three variables were strongly correlated, only the estimate of the fast twitch fiber was considered for the results. The subjects showed a significant improvement in the fast twitch fiber recruitment percentage after the 40 min run. Our data show that submaximal physical exercise determined a change in fast twitch muscle fiber recruitment patterns observed when subjects performed vertical jumps; however, this recruitment capacity was proportional to the subjects’ individual fast twitch muscle fiber profiles measured before the 40 min run. The results of the jump tests did not change significantly after the three-week training period. These results suggest that pre-fatigue methods, through sub-maximal exercises, could be used to take advantage of explosive capacity in middle-distance runners.

Key words

  • squat jump
  • middle distance running
  • lactate threshold
  • fibers
  • recruitment
Otwarty dostęp

Pulmonary Rehabilitation with a Stabilometric Platform After Thoracic Surgery: A Preliminary Report

Data publikacji: 31 Dec 2018
Zakres stron: 79 - 87

Abstrakt

Abstract

The aim of this study was to evaluate the influence of exercises on a stabilometric platform on the physical fitness and mobility of patients with lung cancer after thoracic surgery. The Experimental Group included 22, and the Control Group consisted of 21 patients. All included patients were enrolled after thoracic surgery due to lung cancer. The Experimental and Control Groups were enrolled in a 3-week in-hospital pulmonary rehabilitation program. The Experimental Group additionally performed daily 20-min training sessions on a stabilometric platform. Agility and flexibility were assessed with the Fullerton test before and after rehabilitation in both groups, and quality of life was assessed with the SF-36 questionnaire. Exercise performance stated as a distance in a 6 min walking test (6MWT) significantly improved in both groups with a medium effect size. The results of the Fullerton test indicated improvements in flexibility in both groups after the completion of the program without a significant difference between the groups and with a small effect size. In the Experimental Group, the best results were observed in the Arm curl (p = 0.0001), Chair stand (p = 0.04), Up and go (p = 0.001) and Chair sit and reach (p = 0.0001) tasks. No deterioration in the quality of life was observed in the Experimental or the Control Group after the completion of the program. Between-group analyses revealed significant differences in the Role-Physical (RP) (p = 0.020) and Mental-Health (MH) (p = 0.025) domains of the SF-36. The rehabilitation program with a stabilometric platform improved agility and flexibility of patients after thoracic surgery without an effect size or significant differences between the Experimental and Control Groups.

Key words

  • pulmonary
  • rehabilitation
  • lung cancer
  • physical fitness
  • stabilometric platform
Otwarty dostęp

Does Sodium Citrate Cause the Same Ergogenic Effect as Sodium Bicarbonate on Swimming Performance?

Data publikacji: 31 Dec 2018
Zakres stron: 89 - 98

Abstrakt

Abstract

The aim of this study was to investigate the effect of ingesting sodium bicarbonate (SB) and sodium citrate (SC) on 400 m high-intensity swimming performance and blood responses. Six nationally ranked male swimmers (20.7 ± 2.1 yrs; 184 ± 6 cm; 79.9 ± 3.9 kg; 10.6 ± 1% body fat) participated in a double blinded, placebo controlled crossover trial. Ninety minutes after consuming SB (0.3 g·kg-1), SC (0.3 g·kg-1) or a placebo (PL) participants completed a single 400-m freestyle maximal test on three consecutive days. The order of the supplementation was randomized. Capillary blood samples were collected on 4 occasions: at rest (baseline), 60 min post-ingestion, immediately post-trial and 15 min post-trial. Blood pH, HCO3- concentration and base excess (BE) were determined. Blood pH, HCO3-, BE were significantly elevated from before loading to the pre-test (60 min post-ingestion) (p < 0.05) after SB ingestion, but not after SC ingestion (p > 0.05). Performance times were improved by 0.6% (p > 0.05) after supplementation of SB over PL in 5 out of 6 participants (responders). In contrast, ingestion of SC decreased performance by 0.2% (p > 0.05). No side effects were observed in either trial. Delayed blood response was observed after SC ingestion compared to SB and this provided no or modest ergogenic effect, respectively, for single bout high-intensity swimming exercise. Monitoring the magnitude of the time-to-peak level rise in alkalosis may be recommended in order to individualize the loading time accordingly before commencement of exercise.

Key words

  • dietary supplements
  • ergogenic aid
  • performance
  • nutrition
Otwarty dostęp

Differences in Loading and Morphological Structure of the Take‐off and Non‐take‐off Limb in Athletics Jumping Events

Data publikacji: 31 Dec 2018
Zakres stron: 99 - 109

Abstrakt

Abstract

The objective of the study was to assess differences between the take-off and non-take-off limbs of athletes in track-and-field jumping events based on a segmental analysis of body composition as well as kinetic analysis. The research included 19 participants (10 males, 9 females) with an average age of 18.1 ± 2.8 years. We measured body height, body mass, body composition (body fat, fat free mass, bone mineral content and bone density) and segmental distribution of these variables. To assess strength of the lower limbs, we performed reaction force analysis during take-off and run symmetry. The difference in the representation of soft tissues between the take-off and non-take-off limbs was not significant; the differences were 0.06%, 0 kg in body fat and 0.01 kg in fat free mass. The differences in the values of bone matter were significant. The bone mineral content was 0.05 kg higher in the take-off limb (p < 0.001), and bone density was 0.07 g/cm2 higher (p < 0.001); the practical significance of the difference was intermediate (d = 0.5). Kinetic analysis showed that athletes exerted greater force on the pad with the take-off limb than the non-take-off limb when taking off while using arms in the first peak of the vertical force. The difference determined in this type of take-off was statistically significant (p < 0.05); the practical significance of the difference was medium (d = 0.7). The difference in the second peak of the vertical reaction force in the take-off arm was not statistically significant. The differences were reflected in the different bone matter compositions.

Key words

  • kinetics
  • body composition
  • segmental analysis
  • take-off limb
Otwarty dostęp

The Effect of Physical And Mental Stress on the Heart Rate, Cortisol and Lactate Concentrations in Rock Climbers

Data publikacji: 31 Dec 2018
Zakres stron: 111 - 123

Abstrakt

Abstract

Rock climbing is a physical activity that not only causes an increase in muscle tension, heart rate and blood pressure, but also results in the elevation of stress hormones including cortisol. It has not been established which of the above mentioned variables serve as the most accurate indicator of rock climbing-induced physical and mental stress. The aim of this study was to evaluate the effect of physical activity, short-term fatigue and mental demand on heart rate (HR), salivary cortisol (C) and blood plasma lactate (LA) concentrations in rock climbers under laboratory conditions. Twelve male and female rock climbers of comparable climbing performance (5a – 6b OS) were recruited. The participants completed two routes of different climbing difficulty (effect of physical demand), repeated a difficult route with a short 5-min recovery period three times (effect of fatigue), and repeated a difficult lead climb (effect of mental demand). Heart rate as well as C and LA concentrations were determined. The results indicated that more difficult climbing routes elicited increases in HR (especially relative values) and LA concentrations, whereas fatigue accumulation had an effect on climbing HR and relative C concentration values. Lead climbing only caused an increase in climbing HR. Based on the results it was concluded that HR was a good indicator of physical and mental stress intensity. Performing the same difficult route three times with a short recovery period in-between turned out to be the most demanding task and resulted in the highest increase of the cortisol concentration. Dynamics of changes in lactate concentrations depend on muscle loading (local muscular effort), lactate clearance and technical/tactical skills of the climber.

Key words

  • workload intensity
  • physiological response
  • rock climbing
Otwarty dostęp

No Modification in Blood Lipoprotein Concentration but Changes in Body Composition After 4 Weeks of Low Carbohydrate Diet (LCD) Followed by 7 Days of Carbohydrate Loading in Basketball Players

Data publikacji: 31 Dec 2018
Zakres stron: 125 - 137

Abstrakt

Abstract

Recently, low carbohydrate diets have become very popular due to their numerous health benefits. Unfortunately, little is known about their chronic effects on the blood lipid profile and other cardiovascular disease risk factors in athletic populations. We compared the results of a four week, well-planned low carbohydrate diet (LCD) followed by seven days of carbohydrate loading (Carbo-L) on fasting lipids - triacylglycerol’s (TAG), LDL-C, HDL-C, total cholesterol (TCh), glucose, insulin and HOMA-IR levels in 11 competitive basketball players. During the experiment, we also measured body mass (BM) and body composition changes: body fat (BF), % of body fat (PBF), and fat free mass (FFM). Both diet procedures significantly changed the fasting serum concentration of TAG (p < 0.05) and body fat content (kg and %) (p < 0.05), without negative changes in FFM. The Carbo-L procedure increased (p < 0.05) fasting glucose levels significantly. A LCD may be suggested for athletes who want to reduce body mass and fat content without compromising muscle mass. Several weeks on a LCD does not change the lipoprotein - LDL-C and HDL-C level significantly, while a seven-day Carb-L procedure may increase body fat content and fasting glucose concentration. Such dietary procedures are recommended for team sport athletes to reduce fat mass, lipid profile disorders and insulin resistance.

Key words

  • nutrition
  • competitive athletes
  • lipoprotein profile
  • body mass
  • fat content
  • carbo loading
Otwarty dostęp

Salivary BDNF and Cortisol Responses During High‐Intensity Exercise and Official Basketball Matches in Sedentary Individuals and Elite Players

Data publikacji: 31 Dec 2018
Zakres stron: 139 - 149

Abstrakt

Abstract

Salivary cortisol increases in response to stressors, including physical exertion and psychological stress associated with sports competition. In addition, stress may induce change in brain-derived neurotrophic factor (BDNF). However, there are still no data available to compare the salivary BDNF level in sedentary male individuals and elite team-sport male athletes, regularly involved in activities that require elevated attention and concentration. This information could contribute to the advance of understanding of the effect of regular exercise on the salivary level of BDNF, the pre-to-post change in salivary BDNF during exercise, and the association between salivary cortisol and salivary BDNF responses to physical exercise. Therefore, this study aimed to compare the concentration of salivary cortisol and BDNF, before and after exercise, in sedentary individuals and elite male basketball players. The sedentary group (23.0 ± 4.2 yrs) performed a high-intensity exercise protocol and the basketball players (18.6 ± 0.5 yrs) participated in three official basketball matches. Saliva samples were tested for cortisol and BDNF using ELISA. A significant increase in salivary cortisol from pre- to post-match was observed only for the basketball players (p < 0.05). Basketball players also presented a higher salivary BDNF concentration for both resting (pre) and post-physical exercise (p < 0.05); however, no change in pre- to post-exercise salivary BDNF was observed for either group (p > 0.05). Elevated BDNF in athletes may be associated to their repeated exposure to stressful competition situations. The current findings also suggest that different mechanisms might be involved in salivary cortisol and BDNF responses during physical exercise.

Key words

  • saliva
  • team-sports
  • stress
  • athletes
  • neuroendocrinology
  • exercise
Otwarty dostęp

Exercise‐Based Cardiac Rehabilitation with and without Neuromuscular Electrical Stimulation and its Effect on Exercise Tolerance and Life Quality of Persons with Chronic Heart Failure

Data publikacji: 31 Dec 2018
Zakres stron: 151 - 164

Abstrakt

Abstract

The study compares the effect of an exercise-based cardiac rehabilitation program with a program combining physical exercise and lower extremity neuromuscular electrical stimulation (NMES) on the recovery of patients with chronic heart failure (CHF) with NYHA II-III symptoms. Seventy two patients with stable CHF were randomly distributed to four groups that received exercise-based cardiac rehabilitation and pharmacological treatment. Groups I and II were additionally administered NMES (35 Hz and 10 Hz, respectively) and in Group III sham NMES was applied. Group IV (controls) received solely pharmacological and exercise treatment. Exercise tolerance and quality of life were assessed in patients pre-treatment and at week 3. Three weeks of rehabilitation induced significant increases (p < 0.05) in the distance covered in the 6-minute walk test, the metabolic equivalent (MET), the duration of the treadmill exercise stress test, the left ventricle ejection fraction (LVEF) and improved quality of life in all groups, but between-group differences were not significant (p > 0.05). In none of the groups were the left ventricle end-systolic and end-diastolic diameters (mm) measured at week 3 significantly different from their baseline values (p > 0.05). Exercise-based cardiac rehabilitation contributed to higher exercise tolerance, LVEF and quality of life of CHF patients (NYHA II-III), contrary to cardiac rehabilitation combined with lower extremity NMES (35 Hz and 10 Hz) that failed to induce such improvements. More research is necessary to assess the therapeutic efficacy of NMES applied to CHF patients with NYHA IV symptoms.

Key words

  • physical activity
  • cardiac rehabilitation
  • chronic heart failure
  • neuromuscular electrical stimulation
  • exercise tolerance
  • quality of life

Section III - Sports Training

Otwarty dostęp

Work-rate Analysis of Substitute Players in Professional Soccer: Analysis of Seasonal Variations

Data publikacji: 31 Dec 2018
Zakres stron: 165 - 174

Abstrakt

Abstract

The aims of this study were to evaluate physical performance of substitute players versus those replaced or completing the entire match, determine physical performance of substitute players across different playing positions and examine variations in match-related running performance in substitute players throughout the entire competitive season. The sample was composed of 943 observations of professional players who participated in the first division of the Spanish League (La Liga) during the 2014-2015 season. The players were divided into three different groups: players who completed the entire match (n = 519), players who were replaced (n = 212) and substitute players (n = 212). Substitute players covered greater distances at medium and high intensity compared to the players who played the entire match and those who were replaced. Position-specific trends indicated that attackers and central midfielder increased the distance covered at high-intensity running compared to their peers who played the whole match. During the competitive season, it was observed that substitute players attained greater match running performance during the mid-season period, allowing them to cover more distance for different variables of running performance compared to the start and end of the season.

Key words

  • substitute's performance analysis
  • seasonal variations
  • playing position
  • high-intensity running
Otwarty dostęp

Effects of the Pitch Surface on Displacement of Youth Players During Soccer Match-Play

Data publikacji: 31 Dec 2018
Zakres stron: 175 - 185

Abstrakt

Abstract

The aim of this study was to analyze the effect of different pitch surfaces (artificial turf, natural turf and dirt field) on positioning and displacement of young soccer players (age: 13.4 ± 0.5 yrs; body height: 161.82 ± 7.52 cm; body mass: 50.79 ± 7.22 kg and playing experience: 3.5 ± 1.4 yrs). Data were collected using GPS units which allowed to calculate spatial distribution variability, assessed by measuring entropy of individual distribution maps (ShannEn). Ellipsoidal areas (m2) representing players’ displacement on the pitch, centred on the average players’ positional coordinates, were also calculated, with axes corresponding to the standard deviations of the displacement in the longitudinal and lateral directions. Analysis of variance (ANOVA) was used to evaluate differences between pitch surfaces and across players’ positions. There was significant effect in positioning (η2 = 0.146; p < 0.001) and displacement (η2 = 0.063; p < 0.05) by the players between pitch surfaces. A dirt field condition induced an increase in the players’ movement variability, while players’ displacement was more restricted when playing on artificial turf. Also, there were significant effects on positioning (η2 = 0.496; p < 0.001) and displacement (η2 = 0.339; p < 0.001) across players’ positions. Central midfielders presented the greatest movement variability and displacement while fullbacks showed the lowest variability. Subsequently, the results may contribute to implement strategies that optimise players’ performance in different surface conditions.

Key words

  • movement variability
  • spatial distribution maps
  • performance analysis
  • entropy
  • tactical demands
Otwarty dostęp

Effect of Different Feedback Modalities on Swimming Pace: Which Feedback Modality is Most Effective?

Data publikacji: 31 Dec 2018
Zakres stron: 187 - 195

Abstrakt

Abstract

To compare the effect of three different feedback modalities on swimming pace, sixteen male swimmers and triathletes participated in this study. Each participant swam 3 x 400 m, one for each feedback modality, swimming front crawl at 80% of their individual swimming critical speed. Three feedback modalities were examined: self-pacing, real time visual feedback and real time voice feedback. The swimmers adopted a fast start in all feedback modalities. In the real time voice feedback modality, the data recorded during the second lap (200 m) showed a significant improvement of their swimming pace approaching the swimming pace intended (-1.47 s, p < .01, medium effect size 0.79). A significant improvement toward the swimming pace intended was also noticed at the third split time (300 m) (0.05 s, p < .01, large effect size 0.81) and at the fourth split time (400 m) (0.46 s, p < .01, medium effect size 0.76). In self-pacing, the swimmers were not able to swim in line with the swimming pace intended. In real time visual feedback modality, the swimmers did not show a significant improvement approaching the swimming pace intended. The results revealed that communication with the swimmers using the real time voice feedback induced a significant improvement in their swimming pace and could help the athletes to swim with accurate and consistent pace.

Key words

  • training
  • performance
  • auditory pathways
  • sensory
  • split time
Otwarty dostęp

Relative Age Effect and Long-Term Success in the Spanish Soccer and Basketball National Teams

Data publikacji: 31 Dec 2018
Zakres stron: 197 - 204

Abstrakt

Abstract

The aims of this study were: i) to analyze whether relative age effect occurs in the athletes of the junior national teams and professional athletes in Spain in general and in soccer and basketball, and ii) to compare the long-term success of the players selected for the junior national team between these sports. The samples for this study were Spanish professional soccer (n = 461) and basketball (n = 250) players in the 2013-2014 premier league and players from the junior Spanish soccer (i.e., n = 273; U-17: n = 107; U-19: n = 166) and basketball (i.e., n = 240; U-18: n = 120, U-16: n = 120) teams that classified to play in the European Championships (from 2004 to 2013). Junior players (42.3%) were more frequently born in the 1st quarter of the year than the professional players (30.7%) (χ2(3) = 30.07; p = .001; Vc = .157). This was found in both basketball (χ2(3) = 12.2.; p = .007; Vc = .158) and soccer (χ2(3) = 20.13; p < .001; Vc = .166). Long-term success is more frequent in soccer, where 59.9% of the juniors selected for the national team played later in the premier league, while in basketball that percentage was 39.6% (χ2(1) = 14.64; p < .001; Vc = .201). On the other hand, 79.4% and 39.8% of the professional soccer and basketball players had been previously selected for junior national teams (χ2(1) = 60.2; p < .001; Vc = .386), respectively. The talent selection process should be reviewed as players born in the second half of the year have fewer opportunities to stand out.

Key words

  • talent
  • selection
  • performance
  • soccer
  • basketball
Otwarty dostęp

Intra and Interzone Differences of Attack and Counterattack Efficiency in Elite Male Volleyball

Data publikacji: 31 Dec 2018
Zakres stron: 205 - 212

Abstrakt

Abstract

The primary goal of this study was to identify and explain differences in a volleyball set between winning and defeated teams, based on frequency and efficiency of the attack and counterattack, both overall and from particular zones of the volleyball court. Research was conducted on a randomly chosen sample of 206 sets played in 55 matches of the Men's Champions League. A total of 10555 spikes in the attack and counterattack from various zones of the volleyball court were analyzed. Between-subjects 2×5 factorial ANOVA (Outcome×Zone) was used to identify significant differences between the set outcome and zones or their interaction for both attack and counterattack efficiency. Significant differences were found in the efficiency of spikes in attacks and counterattacks from various zones of the volleyball court and between winning and losing teams. Post-hoc analysis of interaction effects also revealed significant differences. The obtained results substantiate the importance of spiking, both in the attack and counterattack, for winning a volleyball set, and indicate the specific values of spiking in the attack and counterattack from various zones, for both winning and defeated teams. The results of this study can be useful for coaches, in evaluation of player's performance in the match, in planning and programming the training process as well as in the technical and tactical preparation of the team for the tournament.

Key words

  • notational analysis
  • spiking
  • performance quality
  • factorial ANOVA
Otwarty dostęp

Effects of Core Strength Training Using Stable and Unstable Surfaces on Physical Fitness and Functional Performance in Professional Female Futsal Players

Data publikacji: 31 Dec 2018
Zakres stron: 213 - 224

Abstrakt

Abstract

The aim of this study was to assess the effect of core strength training performed on a stable surface (CTS) compared with core strength training performed on an unstable surface (CTU) on physical fitness (jump performance, sprint, and repeated sprint ability (RSA)) and quality of movement (Fundamental Movement Screen) in professional female futsal players. Fourteen professional female futsal players (mean age: 23.7 ± 5.1 years, age range: 18-28 years) were randomly assigned to a CTS (n = 7) or a CTU (n = 7) group. The intervention program was carried out 3 times a week over 6 weeks. Players of both groups performed the same four core-strengthening exercises. The only difference between the two interventions was that the CTU group performed all exercises (i.e., shoulder bridge, side bridge, prone plank, and crunch) on an unstable surface (Togu® Dyn-Air). Within-group analysis showed significant improvements (p < 0.001) in 10 m sprint performance from the pre- to post-test in the CTS (+4.37%) and CTU (+5.00%) groups. Players in both the CTS (+10.39%) and CTU (+11.10%) group also showed significant enhancement in the Functional Movement Screen total score, from the pre-test to post-test. In addition, a significant time effect was also observed for the CTU group in the relative score of the RSA test decreasing from the pre- to post-test (-30.85%). In the between-groups analysis, there were no significant differences between the core strength training groups (CTS vs CTU) in any variable. To conclude, sprint and Functional Movement Screen performance improved following CTS and CTU when conducted in combination with regular futsal training. In addition, CTU had limited benefit in RSA compared to CTS.

Key words

  • resistance training
  • trunk stability
  • Functional Movement Screen
  • explosive strength
  • repeated sprint ability
Otwarty dostęp

Basketball Game-Related Statistics that Discriminate Between European Players Competing in the NBA and in the Euroleague

Data publikacji: 31 Dec 2018
Zakres stron: 225 - 233

Abstrakt

Abstract

This study aimed to identify the game-related statistics that discriminated between Euroleague basketball players and European basketball players playing in the NBA, when competing in the same event (EuroBasket 2015). There was a total of 78 matches played by 24 teams in two groups of analysis: NBA, participants in the European Championship who played in the NBA season of 2014-2015 (n = 26); Euroleague, participants in the European Championship who played in the Euroleague season of 2014-2015 (n = 82). The players’ performance variables were normalized to the time they spent on the court. To identify which variables best discriminated between the NBA and the Euroleague performance profiles, a descriptive discriminant analysis was conducted. Structure coefficients (SC) from the matrix greater than |0.30| were interpreted as meaningful contributors to discriminating between the groups. The results revealed a significant function (p = 0.008, canonical correlation of 0.51, Λ = 0.74, reclassification = 84.2%) and substantial performance differences in game-related statistics much related to the influence of body size (body height and mass), such as two-point field goals made (SC = 0.42) and missed (SC = 0.40), free-throws made (SC = 0.55), defensive rebounds (SC = 0.62), blocks (SC = 0.48) and suffered fouls (SC = 0.34). No differences were found at the level of game-related statistics indirectly related to perception, such as assists, turnovers or steals. Also, the greater body size in NBA players was likely related to higher variability in performance, thus, being an important topic for coaches and recruiters to analyse.

Key words

  • performance profile
  • analysis
  • game-related statistics
  • discriminant scores
Otwarty dostęp

Training Loads and RSA and Aerobic Performance Changes During the Preseason in Youth Soccer Squads

Data publikacji: 31 Dec 2018
Zakres stron: 235 - 248

Abstrakt

Abstract

The aims of this study were to compare the internal training load (ITL) in soccer players of two competitive age groups (under-15 [U-15] and under-19 [U-19]) during an 8-week preseason training period and compare the associated changes in physical performance measures. Eighteen U-15 and twelve U-19 players were monitored over an 8-week period during the preseason phase. The ITL was monitored using the session rating of perceived exertion (RPE) method. Before and after the preseason period, physical performance was assessed by best (RSAbest) and mean (RSAmean) times in a repeated sprint ability (RSA) test and peak velocity derived from the Carminatti test (PVT-CAR). Total weekly ITL increased with age (U-15: 13770 ± 874 AU vs. U-19: 33584 ± 2506 AU; p < 0.001). In addition, U-19 players perceived training sessions as heavier than U-15 players (6.1 ± 0.3 vs. 5.3 ± 0.3 AU, respectively; p < 0.001). After the preseason period, very likely to almost certainly positive changes were observed for all performance measures in both age groups. However, the U-15 group had possibly superior gains in RSAbest (+1.40%, 90%CL -0.29 to 3.05, with ES = 0.35) and likely higher effects in RSAmean (+1.89%, 90%CL 0.04 to 3.70, with ES = 0.53) and PVT-CAR (+2.71%, 90%CL 0.35 to 5.01, with ES = 0.37) compared to the U-19 group. In conclusion, our findings demonstrate that the U-19 group accumulate higher total weekly ITLs than the U-15 group during the preseason phase due to longer and heavier training sessions. However, the U-15 group obtained superior gains in soccer-specific physical abilities while accumulating half the total ITLs during lighter training sessions.

Key words

  • field testing
  • physical adaptation
  • rating of perceived exertion
  • team sports
  • youth athletes
Otwarty dostęp

Technical and Training Related Aspects of Resistance Training Using Blood Flow Restriction in Competitive Sport - A Review

Data publikacji: 31 Dec 2018
Zakres stron: 249 - 260

Abstrakt

Abstract

Blood flow restriction (BFR) combined with resistance training (RT-BFR) shows significant benefits in terms of muscle strength and hypertrophy. Such effects have been observed in clinical populations, in groups of physically active people, and among competitive athletes. These effects are comparable or, in some cases, even more efficient compared to conventional resistance training (CRT). RT-BFR stimulates muscle hypertrophy and improves muscle strength even at low external loads. Since no extensive scientific research has been done in relation to groups of athletes, the aim of the present study was to identify technical, physiological and methodological aspects related to the use of RT-BFR in competitive athletes from various sport disciplines. RT-BFR in groups of athletes has an effect not only on the improvement of muscle strength or muscle hypertrophy, but also on specific motor abilities related to a particular sport discipline. The literature review reveals that most experts do not recommend the use RT-BFR as the only training method, but rather as a complementary method to CRT. It is likely that optimal muscle adaptive changes can be induced by a combination of CRT and RT-BFR. Some research has confirmed benefits of using CRT followed by RT-BFR during a training session. The use of BFR in training also requires adequate progression or modifications in the duration of occlusion in a training session, the ratio of exercises performed with BFR to conventional exercises, the value of pressure or the cuff width.

Key words

  • occlusion
  • resistance exercise
  • training variables
  • sports performance

Section IV - Behavioural Sciences in Sport

Otwarty dostęp

Cognitive Scripts, Anxiety and Styles of Coping with Stress in Teenagers Practising Sports

Data publikacji: 31 Dec 2018
Zakres stron: 261 - 271

Abstrakt

Abstract

The aim of the study was to present the relationships between the way of perceiving oneself and the world by young athletes, the cognitive anxiety and the ways of coping with stress. The target group consisted of 222 participants (114 boys and 108 girls) aged 16–20, students of sports-profiled secondary schools. The participants specialised in both winter and summer sports, as well as in individual and team sport disciplines. The following tools were implemented: Attitudes to Intrapersonal, Interpersonal and to the World Questionnaire, Coping Inventory for Stressful Situations (CISS) and Sport Anxiety Scale. The study showed that negative perception of oneself and others increases the level of cognitive anxiety and decreases the tendencies to search for social contacts in the face of stress. With regard to the positive image of oneself and others, the opposite was observed. The above relationships refer mainly to girls who practise sports.

Key words

  • image
  • image of the world
  • coping with stress
  • cognitive and somatic anxiety
  • youth
  • sport
Otwarty dostęp

Moral Behavior in the Locker Room Predicts Perceptions of Task Cohesion in Youth Ice Hockey Player

Data publikacji: 31 Dec 2018
Zakres stron: 273 - 280

Abstrakt

Abstract

Task cohesion (i.e., perceptions of team unity towards a task goal and positive feelings towards one’s own involvement) is associated with myriad psychosocial benefits for youth athletes. Accordingly, sport researchers and youth sport stakeholders are interested in ways of fostering task cohesion. Recent work has found evidence that prosocial and antisocial behaviors among teammates are associated with athletes’ perceptions of task cohesion; however, this research has been limited to moral behavior that takes place during gameplay. Despite youth sport experiences extending well beyond practices and games, we know very little about how moral behavior between teammates, in settings outside gameplay, relates to perceptions of task cohesion. To address this knowledge gap, the current study investigated whether prosocial and antisocial behaviors in the locker room setting were associated with perceptions of task cohesion in a sample of 238 youth male ice hockey players (Mage = 10.75). Using hierarchical regression analyses, our results revealed that (a) perceptions of peer prosocial behavior was positively associated with task cohesion, (b) perceptions of peer antisocial behavior was negatively associated with task cohesion, and (c) self-reported perceptions of participants’ own moral behavior was not significantly associated with task cohesion. Given the association with perceptions of task cohesion, these findings underline the value in promoting prosocial behavior and reducing antisocial behavior in sport settings outside gameplay and hold multiple theoretical and practical implications. Notably, moral behavior that takes place outside gameplay settings may be related to perceptions of task cohesion that primarily relates to goals and interactions during gameplay.

Key words

  • youth sport
  • group dynamics
  • prosocial behavior
  • antisocial behavior
  • adult supervision
Otwarty dostęp

Relations Among Reinvestment, Self-Regulation, and Perception of Choking Under Pressure

Data publikacji: 31 Dec 2018
Zakres stron: 281 - 290

Abstrakt

Abstract

The purpose of this study was to examine relations among reinvestment, self-regulation, and perception of choking under pressure in skilled tennis players. Participants were 160 collegiate players from the NCAA Division I in the U.S. and the 1st League in Japan. Participants completed questionnaires assessing reinvestment (conscious motor processing and movement self-consciousness), self-regulation, and perception of choking under pressure. Results of correlation analysis indicated self-regulatory factors were positively related to reinvestment conscious motor processing, but not with reinvestment movement self-consciousness. Self-efficacy and movement self-consciousness of reinvestment were found to predict one’s perception of choking under pressure. Results of simultaneous entry multiple regression revealed that tennis players who had low self-efficacy and were concerned about making a good impression with their movements were more likely to perceive that they choked during tennis matches. Additionally, Japanese players reported less self-regulation skills and a higher perception of choking under pressure than American players, suggesting the need for additional research on cross-cultural differences. Overall, these results suggest that self-efficacy may protect athletes from choking, but movement self-consciousness may lead athletes to choke during tennis games.

Key words

  • self-focus
  • metacognition
  • self-efficacy
  • collegiate athletes
  • cross-cultural comparison
Otwarty dostęp

The mediation effect of Perceived Social Support and Perceived Stress on the relationship between Emotional Intelligence and Psychological Wellbeing in Male Athletes

Data publikacji: 31 Dec 2018
Zakres stron: 291 - 303

Abstrakt

Abstract

This study aimed to examine the relationship between emotional intelligence (EI) and psychological wellbeing in a three-month follow-up study of male athletes. In addition, we examined the mediating role of perceived social support and perceived stress on the relationship between EI and psychological wellbeing. The sample included 398 male athletes who completed measures of emotional intelligence (Schutte Self-Report Inventory), psychological wellbeing (Ryff Psychological Wellbeing Scale; SSRI), perceived social support (Multidimensional Scale of Perceived Social Support), and perceived stress (Perceived Stress Scale–10). Results from structural equation modelling procedures identified that perceived social support and perceived stress partially mediated the association between EI and psychological wellbeing. The sequential mediation effects of perceived social support–perceived stress on the relations between EI and wellbeing were confirmed. Finally, limitations and recommendations for future research were considered

Key words

  • emotional intelligence
  • psychological wellbeing
  • perceived social support
  • perceived stress
  • athletes

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