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Dettagli della rivista
Formato
Rivista
eISSN
1899-7562
Pubblicato per la prima volta
13 Jan 2009
Periodo di pubblicazione
5 volte all'anno
Lingue
Inglese

Cerca

Volume 69 (2019): Edizione 1 (October 2019)

Dettagli della rivista
Formato
Rivista
eISSN
1899-7562
Pubblicato per la prima volta
13 Jan 2009
Periodo di pubblicazione
5 volte all'anno
Lingue
Inglese

Cerca

27 Articoli

Section I - Kinesiology

Accesso libero

Application of Virtual Reality in Competitive Athletes – A Review

Pubblicato online: 18 Oct 2019
Pagine: 5 - 16

Astratto

Abstract

The purpose of this study was to determine the state of the art in the area of virtual reality in competitive athletes of different levels of expertise in various disciplines and point the areas of its application. Articles published before August 2018 were considered in our review. The PubMed, SCOPUS, SportDiscus and Medline databases were searched. A combination of the following search terms was used: virtual reality, virtual environment, virtual system, athletes, sports, physical training, sport performance, physical exercises. Studies involved healthy competitive athletes. A total of 18 articles met the inclusion criteria. There were three areas of application of virtual reality to sport: performance analysis, simulation improvement and virtual training. Competitive athletes were mostly examined in a semi‐immersive setting. In conclusion, virtual reality seems to play a marginal role in competitive athletes’ training. Due to the fact that virtual reality interventions bring significant improvements in clinical research, well‐designed randomized control trials with detailed virtual training programmes are required in the future. Practically, virtual reality is effectively and commonly used to analyse performance in competitive athletes. There is still a need of creating fully interactive VR, where athletes will be able to cooperate with a virtual partner and influence the environment.

Key words

  • sport simulation
  • immersion
  • training
  • athletic performance
Accesso libero

Reaction to a Visual Stimulus: Anticipation with Steady and Dynamic Contractions

Pubblicato online: 18 Oct 2019
Pagine: 17 - 27

Astratto

Abstract

Reacting fast to visual stimuli is important for many activities of daily living and sports. It remains unknown whether the strategy used during the anticipatory period influences the speed of the reaction. The purpose of this study was to determine if reaction time (RT) differs following a steady and a dynamic anticipatory strategy. Twenty‐two young adults (21.0 ± 2.2 yrs, 13 women) participated in this study. Participants performed 15 trials of a reaction time task with ankle dorsiflexion using a steady (steady force at 15% MVC) and a dynamic (oscillating force from 10‐20% MVC) anticipatory strategy. We recorded primary agonist muscle (tibialis anterior; TA) electromyographic (EMG) activity. We quantified RT as the time interval from the onset of the stimulus to the onset of force. We found that a dynamic anticipatory strategy, compared to the steady anticipatory strategy, resulted in a longer RT (p = 0.04). We classified trials of the dynamic condition based on the level and direction of anticipatory force at the moment of the response. We found that RT was longer during the middle descending relative to the middle ascending and the steady conditions (p < 0.01). All together, these results suggest that RT is longer when preceded by a dynamic anticipatory strategy. Specifically, the longer RT is a consequence of the variable direction of force at which the response can occur, which challenges the motor planning process.

Key words

  • reaction time
  • anticipation
  • steady contraction
  • sinusoidal contraction
Accesso libero

Differences in Mechanical Midsole Characteristics of Running Shoes Do Not Influence Physiological Variables in Aerobic and Anaerobic Running

Pubblicato online: 18 Oct 2019
Pagine: 29 - 38

Astratto

Abstract

The purpose of this study was to determine the influence of footwear stiffness and energy loss on oxygen uptake and heart rate in athletes running under aerobic and anaerobic conditions. Four footwear conditions with identical outsoles, insoles, upper materials, but different mechanical properties regarding polyurethane midsole materials were investigated. Respective midsole material characteristics were selected to represent a wide range of running shoes. The test procedure for eighteen well‐trained male runners was divided into three treadmill testing sessions: an incremental ramp protocol to estimate the individual ventilatory threshold (day 1), a test with 6‐minute stages in each shoe at 70% (aerobic, day 2) and 102% (anaerobic, day 3) of the participant’s ventilatory threshold. For oxygen uptake and the heart rate, no significant differences between footwear conditions were found for either running condition. Furthermore, no significant relationships between physiological variables and mechanical midsole characteristics were found. The wide range of significant stiffness differences in the rearfoot (52.7 N/mm) and forefoot areas (50.7 N/mm), as well as significant differences of the shoe midsole material energy loss in the rearfoot (18.8%) and forefoot areas (10.7%) were too low to influence physiological variables significantly when running below and slightly above the ventilatory threshold. It seems that shoe mass and shoe comfort can influence physiological variables more than the mechanical midsole characteristics of stiffness and energy loss. These results may have practical implications for shoe manufacturers, coaches, and athletes, alike.

Key words

  • footwear
  • midsole stiffness
  • energy loss
  • running
  • oxygen uptake
  • heart rate
Accesso libero

The Relationship Between Pistol Olympic Shooting Performance, Handgrip and Shoulder Abduction Strength

Pubblicato online: 18 Oct 2019
Pagine: 39 - 46

Astratto

Abstract

The ability to stabilize the gun, a crucial factor for performance in air pistol Olympic shooting, is thought to be strongly related to the muscular work of the shooter´s shoulder and forearm. The objective of the present study was to confirm this relationship by analysing the influence of maximal finger flexor forces and maximal isometric shoulder force on performance in female air pistol shooting. Twenty‐three female pistol shooters participated in the study. Handgrip and shoulder force data were recorded under competition conditions, during the official training time of national Spanish championships on the day previous to the competition and at the official training stands. Performance was measured as the total score of 40 shots at competition. Linear regressions between performance and age, weight, height, training experience, body mass index (BMI), mean and maximal finger flexor and shoulder forces were calculated. Significant correlations were found between performance and a) training hours b) peak finger flexor force relative to the BMI, and c) peak isometric force of the shoulder abduction relative to the BMI. The study concludes that there is a statistically significant correlation between performance and muscular forces exerted by the athletes relative to their BMI. Appropriate muscular strength training programs are therefore necessary in female air pistol Olympic shooting.

Key words

  • score
  • deltoid force
  • dynamometer
  • BMI
  • performance
Accesso libero

Is Test Standardization Important when Arm and Leg Muscle Mechanical Properties are Assessed Through the Force‐Velocity Relationship?

Pubblicato online: 18 Oct 2019
Pagine: 47 - 58

Astratto

Abstract

The force‐velocity (F‐V) relationship observed in multi‐joint tasks proved to be strong and approximately linear. Recent studies showed that mechanical properties of muscles: force (F), velocity (V) and power (P) could be assessed through the F‐V relationship although the testing methods have not been standardized. The aim of the present study was to evaluate and compare F‐V relationships assessed from two tests performed on a modified Smith machine that standardizes kinematics of the movement pattern. Fifteen participants were tested on the maximum performance bench press throws and squat jumps performed against a variety of different loads. In addition, their strength properties were assessed through maximum isometric force (Fiso) and one repetition maximum (1 RM). The observed individual F‐V relationships were exceptionally strong and approximately linear (r = 0.98 for bench press throws; r = 0.99 for squat jumps). F‐V relationship parameter depicting maximum force (F0) revealed high correlations with both Fiso and 1 RM indicating high concurrent validity (p < 0.01). However, the generalizability of F‐V relationship parameters depicting maximum force (F0), velocity (V0) and power (P0) of the tested muscle groups was inconsistent and on average low (i.e. F0; r = ‐0.24) to moderate (i.e. V0 and P0; r = 0.54 and r = 0.64, respectively; both p < 0.05). We concluded that the F‐V relationship could be used for the assessment of arm and leg muscle mechanical properties when standard tests are applied, since the typical outcome is an exceptionally strong and linear F‐V relationship, as well as high concurrent validity of its parameters. However, muscle mechanical properties could be only partially generalized across different tests and muscles.

Key words

  • generalizability
  • concurrent validity
  • parameter
  • power
  • load
Accesso libero

Regulation of Stride Length During the Approach Run in the 400‐M Hurdles

Pubblicato online: 18 Oct 2019
Pagine: 59 - 67

Astratto

Abstract

This research aims to clarify the stride adjustment in the approach of the 400‐m hurdles, and to examine the relationship with 400‐m hurdle performance. Seven male 400‐m hurdlers volunteered for this study. Participants ran three times from the start to the second hurdle. The standard deviation of toe‐hurdle distance and standard deviation of stride length at each step from the start to the first hurdle were calculated. The maximum value of the standard deviation of toe‐hurdle distance was defined as the position at which the athlete starts stride adjustment. The relationships between each variable, 400‐m hurdle personal best, and the ratio of 400‐m hurdle personal best and 400‐m running personal best (400 m/400‐m hurdles) were examined. Results concluded that standard deviation of toe‐hurdle distance gradually increased after the start, reached the maximum value in the latter half of the approach section, and then decreased until the takeoff. Standard deviation of stride length increased significantly from 4 steps before the takeoff. From these trends, it was suggested that athletes seemed to start stride adjustment from the middle stage to the latter half of the approach by sensing stride error accumulation in the middle of the approach. The strides immediately before the takeoff were markedly involved in stride adjustment. Furthermore, the stride adjustment technique to reduce maximum accumulation error of stride evaluated in the approach section was considered associated with the smooth running of the entire 400‐m hurdle race.

Key words

  • hurdles
  • maximum accumulation error
  • stride length
  • standard deviation of toe‐hurdle distance
Accesso libero

Less Than One Millimeter Under the Great Toe is Enough to Change Balance Ability in Elite Women Handball Players

Pubblicato online: 18 Oct 2019
Pagine: 69 - 77

Astratto

Abstract

Team handball is a complex intermittent sport game, which requires several motor abilities and effective postural control. Objective evaluation of stabilometric variables may be interesting to assess and improve functional parameters by postural control management. The purpose of the study was to evaluate the effects of a small additional thickness placed under the great toe (TUGT) on the Centre of Pressure (CoP) parameters in elite women handball players. Fourteen elite women handball players voluntarily participated in this study. Two conditions were compared: TUGT 0 (control) and TUGT 0.8 mm; four variables were computed from the CoP displacements. A paired T‐test was performed for each variable. This study concludes that a low focal additional thickness placed under both great toes has an effect on the CoP measures used to assess postural control during an unperturbed stance. These results suggest that a low TUGT could contribute to a change in balance ability, and may be of clinical interest. This brings new perspectives in the management of athletes to prevent injury risk and optimize performance.

Key words

  • postural insoles
  • balance ability
  • toes

Section II - Exercise Physiology & Sports Medicine

Accesso libero

Relationships Between the Expression of the ACTN3 Gene and Explosive Power of Soccer Players

Pubblicato online: 18 Oct 2019
Pagine: 79 - 87

Astratto

Abstract

Muscle strength and maximal speed are factors determining athlete’s results during competition. Their association with ACTN3 gene activity has been documented. The purpose of this study was the analysis of ACTN3 gene expression during a 2 month training cycle of soccer players and its correlation with the countermovement jump (CMJ) and squat jump (SJ). The study group consisted of 22 soccer players (aged 17‐18). The study material included peripheral blood lymphocytes. The relative expression (RQ) of the ACTN3 gene was analyzed by qPCR and performed before and after the two‐month training cycle. Before the training cycle low expression levels of ACTN3 (median RQ = 0.95) were observed, yet after the training cycle they were elevated (median RQ = 1.98) ( p = 0.003). There was an increase in performance of both jumps: SJ (p = 0.020) and CMJ (p = 0.012) at the end of the training cycle. A simultaneous increase in the ACTN3 gene expression level and height in both jump tests was observed in 73% of athletes (p > 0.05). There were no significant relationships between the ACTN3 gene expression level and the results of the CMJ and SJ. However, explosive strength is a complex feature shaped by many different factors and it could be the reason why we did not observe correlations between these variables.

Key words

  • α‐actinin‐3 gene
  • soccer players
  • explosive power
  • squat jump
  • counter movement jump
Accesso libero

Cardiovascular and Perceived Effort in Different Head‐Out Water Exercises: Effect of Limbs’ Action and Resistance Equipment

Pubblicato online: 18 Oct 2019
Pagine: 89 - 97

Astratto

Abstract

The aim of this study was to compare the cardiovascular and perceived effort of head‐out water exercises selecting different limb strategies and using resistance equipment. Ten young women were randomly assigned to perform at 132 bpm during five minutes different head‐out aquatic exercises: (i) horizontal arms abduction (Ab); (ii) horizontal arms abduction with dumbbells (AbD); (iii) frontal kick (Fk); (iv) frontal kick with leggings (FkLeg), and; (v) aquatic skiing (Ski). Cardiovascular effort was measured by monitoring the heart rate, blood pressure and double product. Perceived effort was assessed by the Borg’s scale. Within‐routines comparison was computed using repeated‐ measures ANOVA followed‐up by the Bonferroni post‐hoc test. Considering the percentage of the maximal heart rate, participants reached 72.88 ± 12.90% in the FkLeg, 65.99 ± 10.91% in the Fk, 62.62 ± 7.20% in Ski, 57.27 ± 11.58% in AbD and 57.12 ± 12.09% in Ab. Comparing exercises, higher heart rates were observed in the FkLeg (140.40 bpm) than Ab (110.30 bpm) or AbD (110.00 bpm). Significant differences were found in the systolic blood pressure when compared to the Fk (120.60 mmHg) and Ab (104.50 mmHg). Double product was higher in the FkLeg (16990) showing a meaningful difference when compared to Ab (11608) or AbD (12001). The highest perceived effort was found in the FkLeg (15.80) with meaningful variations compared to Ab (11.70), the Fk (13.70) and Ski (10.40). Thus, different head‐ out water exercises result in different intensities. The actions by lower limbs promote a higher cardiovascular response, whereas the upper limbs actions trigger a lower exertion. Moreover, exercising the four limbs concurrently seems to be less intense than using only two limbs with an aid.

Key words

  • aquatic exercise
  • segmental action
  • buoyancy devices
  • heart rate
  • perceived exertion
Accesso libero

The Acute Effects of High‐Intensity Cycling Exercise on Arterial Stiffness in Adolescent Wrestlers

Pubblicato online: 18 Oct 2019
Pagine: 99 - 107

Astratto

Abstract

The aim of this study was to determine the acute effects of high‐intensity cycling exercise on the variables of carotid artery compliance, distensibility and beta stiffness index in elite adolescent wrestlers. The subjects were elite athletes competing in national, European and World Championships, who attended a training camp in the province of Kahramanmaras organized by the Turkish Centre for Olympic Preparation. The study sample comprised 31 male elite wrestlers with a mean age of 15.90 ± 0.87 years, body height of 165.97 ± 9.7 cm and body mass of 66.3 ± 18.45 kg. The arterial stiffness variables of the wrestlers were measured with high‐resolution Doppler ultrasonography before and 5 min after 30 s of high‐intensity cycling exercise (the Wingate Anaerobic Cycling test). The results showed a statistically significant correlation between mean power performance and carotid artery compliance at the 5th min after a single cycling sprint exercise (p < 0.05). No correlation was determined between peak power and the arterial stiffness variables (p > 0.05). The study results indicate that acute changes in arterial stiffness variables are associated with the performance level of high‐intensity cycling exercise in a group of elite adolescent wrestlers.

Key words

  • sprint performance
  • anaerobic exercise
  • arterial sclerosis
Accesso libero

Can Anthropometric Variables and Maturation Predict the Playing Position in Youth Basketball Players?

Pubblicato online: 18 Oct 2019
Pagine: 109 - 123

Astratto

Abstract

Anthropometric diagnoses predict the most appropriate on‐court position for a certain player and are important in the long‐term planning of basketball training programs. This study provides anthropometric characteristics and body composition profiles of Polish youth national team players (U‐14, U‐15, U‐16 and U‐18). The aim of this research was to determine the somatic characteristics of basketball players regarding particular on‐court positions. The sample population consisted of 109 elite basketball players, who played in national teams in four age categories: U‐14, U‐16, U‐18 U‐20. An analysis of the obtained results revealed differences between the younger (U‐14, U‐15 and U‐16) and older groups (U‐18 and U‐20) in terms of length, width and circumference measurements and body mass (3.6–9.3%), as well as subcutaneous fat measured by the skinfold thickness method (14.3–33.7%). ANCOVA with maturity offset as the covariate variable showed differences in body height (p < 0.05, R2 = 0.74) and the arm span (p < 0.05, R2 = 0.87) between each playing position; the somatic measurements were greater for centers than for forwards and guards, and the measurements were greater for forwards than for guards. The somatic feature measurements also increased linearly with age. We can conclude that the arm span and body height are two major somatic factors that can predict center and guard playing positions for national team basketball players in all age categories from U‐14 to U‐20.

Key words

  • anthropometric indicators
  • somatotype
  • peak height velocity
  • professional sport
  • selection
  • basketball players
Accesso libero

Practical Use of the Navigate Pain Application for the Assessment of the Area, Location, and Frequency of the Pain Location in Young Soccer Goalkeepers

Pubblicato online: 18 Oct 2019
Pagine: 125 - 135

Astratto

Abstract

Next to winning, minimizing injuries during training and matches is one of the primary goals of professional team sports games. Soreness and pain can be early indicators and risk factors for acute or long‐term injuries. Monitoring pain intensity and duration, as well as potential sources, are useful for planning practices and can be effective means for preventing injury. The aim of this study was to assess the areas and locations of pain in young soccer goalkeepers during a training camp, and to differentiate the area and frequency between pain arising from the muscles (MP), joints (JP), or as a result of an impact (IP). Recordings of the MP, JP, and IP location along with the area were performed using digital body mapping software (Navigate Pain Android app, Aalborg University, Denmark) installed on a tablet personal computer at the end of each training day across a 5‐day training camp. There was a significant difference in the area between the three types of pain (p < 0.001). The post hoc analysis revealed statistically significant differences between the pixel areas of IP versus JP (p < 0.001), IP versus MP (p < 0.001), and JP versus MP (p < 0.001). There was no significant time‐effect for the IP area between 1‐5 days of training (p = 0.610), neither for MP (p = 0.118) or JP (p = 0.797) and no significant difference for all three pain areas between the front and the back side of the body. The body regions most often reported for MP were thighs, while for JP they were groin and hips, and for IP the hips, shoulders, and forearms were most frequently indicated. This is the first study to map and report the pain distribution associated with training across a 5‐day training camp in soccer goalkeepers, and these findings emphasize the value of using digital pain drawings clinically as well as for monitoring the health status of soccer players.

Key words

  • pain
  • navigate pain
  • soccer
  • goalkeepers training
Accesso libero

International Standards for the 3‐Minute Burpee Test: High‐ Intensity Motor Performance

Pubblicato online: 18 Oct 2019
Pagine: 137 - 147

Astratto

Abstract

The aim of this study was to develop international standards for evaluating strength endurance with the use of the 3‐Minute Burpee Test. The results of 3862 women (Poland – 2502, Great Britain – 500, Hungary – 412, Serbia – 448) and 5971 men (Poland – 4517, Great Britain – 500, Hungary – 451, Serbia – 503) aged 18‐25 (mean age of 20.36 ± 0.94 and 20.05 ± 1.25 y, respectively) were collated between 2004 and 2018. The students’ strength endurance was evaluated in the 3‐Minute Burpee Test. The results were expressed on a uniform scale with the 3‐sigma rule which was used to develop the T‐score scale for the 3‐Minute Burpee Test. Men completed 56.69 cycles/3 min and women – 48.84/3 min on average. The best male participant completed 82 burpees, and the best female participant – 73 burpees. The majority of male and female participants (66.71% and 68.18%, respectively) were characterized by average strength endurance in the 3‐Minute Burpee Test (range of scores: 47‐66 and 37‐60 cycles/3 min, respectively). Very good strength endurance (76‐85 and 72‐83 cycles/3 min, respectively) was noted in the smallest percentage of male and female participants (0.52% and 0.26%, respectively). Similar studies should be carried out in other countries and in different age groups to develop objective international classification standards for variously‐aged individuals.

Key words

  • strength endurance
  • extreme effort
  • 3‐MBT
  • norms
Accesso libero

Effect of Virtual Reality‐Based Rehabilitation on Physical Fitness in Patients with Chronic Obstructive Pulmonary Disease

Pubblicato online: 18 Oct 2019
Pagine: 149 - 157

Astratto

Abstract

The aim of the study was to evaluate the effects of rehabilitation in patients with chronic obstructive pulmonary disease (COPD) using the Kinect system during stationary rehabilitation. The study included 68 patients with COPD (35 men, 33 women, mean age 61.3 ± 3.7). The subjects were randomly assigned to one of the two experimental groups described below. Group I included 34 patients – non‐participants in Kinect training. Group II included 34 patients – participants in Kinect training. In all patients before and after rehabilitation physical fitness was assessed using the Senior Fitness Test (SFT). The Xbox 360 and Kinect motion sensor were used to carry out virtual reality training. In group I, statistically significant improvements in SFT performance were observed. Patients in group II also showed statistically significant improvement in physical fitness in all attempts of the SFT. Virtual rehabilitation training in patients with COPD seems to be a practical and beneficial intervention capable of enhancing mobility and physical fitness.

Key words

  • virtual rehabilitation
  • COPD
  • physical fitness
  • virtual reality
  • pulmonary rehabilitation
Accesso libero

Predicting Competition Performance in Short Trail Running Races with Lactate Thresholds

Pubblicato online: 18 Oct 2019
Pagine: 159 - 167

Astratto

Abstract

Trail running is a popular sport, yet factors related to performance are still not fully understood. Lactate thresholds have been thoroughly investigated in road running and correlate strongly with race performance, but to date few data are available about the value in trail running performance prediction. We examined 25 trail runners (age 31.2 ± 5.1 years, BMI 22.2 ± 1.82 kg/m2) with an initial graded exercise test for measurement of VO2max (59.5 ± 5.2 ml.kg‐1.min‐ 1) and lactate thresholds (LT): LTAET (LT aerobic) 1.03 ± 0.59 mmol/l; 11.2 ± 1.1 km/h), IAT (individual lactate threshold) (2.53 ± 0.59 mmol/l; 15.4 ± 1.6 km/h) and LT4 (lactate threshold at 4 mmol/l) (16.2 ± 1.9 km/h). All runners subsequently participated in a 31.1 km XS trail race and 9 runners in a 21 km XXS trail race. Race performance times correlated negatively with the XS trail run (LTAET: r = ‐0.65, p < 0.01; LT4: r = ‐0.87, p < 0.01; IAT: r = ‐0.84, p < 0.01) and regression analysis showed that race performance could be predicted by: LT4: ‐324.15×LT4+13195.23 (R2 = .753, F1,23 = 70.02, p < 0.01). A subgroup analysis showed higher correlations with race performance for slower than faster runners. No correlations were found with the XXS race. Lactate thresholds can be of value in predicting trail race performance and help in designing training plans.

Key words

  • anaerobic threshold
  • exercise test
  • exercise
  • endurance
  • athletic performance
Accesso libero

Effects of Terbutaline Sulfate on Physiological and Biomechanical as Well as Perceived Exertion in Healthy Active Athletes: A Pilot Study

Pubblicato online: 18 Oct 2019
Pagine: 169 - 178

Astratto

Abstract

This study aimed to investigate the effects of beta2‐agonist terbutaline sulfate (TER) at a supra‐therapeutic dose (8 mg) on aerobic exercise performance. Twelve (6 females and 6 males) amateur athletes familiarized with all experimental procedures had their anthropometric data obtained on day 1. On days 2 and 3 either 8 mg of TER or a placebo (PLA) was administered orally (double‐blind manner) to participants who had rested for 3 h prior to aerobic exercise performance 20 m multistage fitness test (MSFT)]. This test was used to predict maximal oxygen uptake (VO2max) and velocity at which VO2max occurs (vVO2max). The Borg rating of perceived exertion (RPE), cardiovascular variables [heart rate (HR) and blood pressure (BP)] and blood glucose concentration [BGC] were obtained 15 min pre‐ and immediately post‐MSFT. Significant mean group differences were reported between PLA and TER groups (p < 0.05), respectively, in the RPE (15.6 ± 1.2 vs. 17.3 ± 1.5 a.u.), maximum heart rate (HRmax: 191.2 ± 7.1 vs. 197.2 ± 8.6 bpm) and BGC (118.4 ± 18.3 vs. 141.2 ± 15.8 mg/dL) post‐MSFT. The main effect of gender (male vs. female) in TER and PLA groups (p< 0.05) was observed, with higher estimated VO2max, vVO2max, HRmax and a lower mean HR pre‐test in male than female athletes. For these reasons, the inclusion of TER in the Prohibited List should be re‐discussed because of the lack of ergogenic effects.

Key words

  • β2‐agonist
  • doping
  • blood glucose concentration
  • blood arterial pressures
  • heart rate
Accesso libero

No Pain, No Gain? Prevalence, Location, Context, and Coping Strategies with Regard to Pain Among Young German Elite Basketball Players

Pubblicato online: 18 Oct 2019
Pagine: 179 - 189

Astratto

Abstract

Pain among young athletes requires special attention given that symptoms occur during the ongoing development of the conditional, and in particular, the motor capacities, and while the musculoskeletal system is in a continuous process of growth. The purpose of this study was to evaluate prevalence, location, context, and coping strategies regarding pain among young athletes. We chose survey data of young elite athletes from the highest level national basketball leagues in Germany, as this meant that health implications may be observed earlier and in a more pronounced manner. The German ‘Adolescents’ and Children’s Health in Elite Basketball study’ (ACHE study), a quantitative survey, was conducted between April and June 2016. Analyses were based on elite basketball players between 13 and 19 years of age from 46 German teams (n = 182). Constant, and to some extent severe pain, was part of daily life of young elite basketball players: eight out of ten players in the highest German leagues suffered from pain at the time of the survey. Knee, leg, and back pain occurred most frequently. For most players, occasional or frequent consumption of analgesics was the norm, in some cases these were also taken “prophylactically”. The consumption of multiple pharmaceutical substances, especially of cyclooxygenase inhibitors such as ibuprofen and diclofenac, is widespread among adolescent elite basketball players. Physicians involved in treating these athletes should address pain and its management preemptively. Coaches, sporting organizations and parents should be involved in this process from an early stage.

Key words

  • pain
  • athletes
  • adolescent
  • analgesics
  • basketball

Section III - Sports Training

Accesso libero

Analysis of Successful Offensive Play Patterns by the Spanish Soccer Team

Pubblicato online: 18 Oct 2019
Pagine: 191 - 200

Astratto

Abstract

Victory is the ultimate aim in soccer and therefore when a team wins an elite European or world championship, attempts will invariably be made to emulate the winning team’s style of play. In this study, we performed an in‐depth analysis of play by the Spanish soccer team during the 2012 UEFA European Championship, where it was crowned champion. Using observational methodology and T‐pattern analysis, we identified hidden patterns of play that ended in a goal for the Spanish team. A generalizability coefficient (e2) of 0.986 demonstrated that the offensive patterns detected are robust and highly generalizable. These patterns were formed by technical actions consisting of ball control and pass, with alternations between short and long passes, in the central area of the rival pitch, with use of both wings to achieve width of play and prioritization of width over depth of play. We also found patterns showing that goals and shots at goal were made on a ball delivered from the opposite direction to the shot and were not preceded by a technical action.

Key words

  • team sport
  • performance
  • game analysis
  • tactics
Accesso libero

Variability of Technical Actions During Small‐Sided Games in Young Soccer Players

Pubblicato online: 18 Oct 2019
Pagine: 201 - 212

Astratto

Abstract

The purpose of this study was three‐fold: (i) to test the between‐sessions variability of 3 vs. 3 and 6 vs. 6 formats in under‐11 players, (ii) to assess the within‐session variability of 3 vs. 3 and 6 vs. 6 formats, and (iii) to investigate the variations of technical actions between formats. Sixteen soccer players (10.1 ± 0.3 years old) participated in this study. Both formats of play were played twice within an interval of one week to test the between‐session variability and the variables of conquered balls (CBs), received balls (RBs), lost balls (LBs), attacking balls/passes (ABs) and shots (Ss) were analyzed using the Performance Assessment in Team Sports instrument in all matches. Moderate variations on the sum of sets during the 3 vs. 3 and 6 vs. 6 formats were observed in all variables. Considering the variations of technical actions made between sets in the 3 vs. 3 format, likely moderate increases were found in set 2 vs. 1 in terms of RB (37.5%, [‐2.7;94.2]), and likely small decreases were found in set 3 vs. 2 for the same variable (‐18.3%, [‐37.8;7.3]). In the 6 vs. 6 format, only possibly small increases were found for set 3 vs. 1 in S (22.5%, [‐7.0;61.3]). Generally (sum of sets), the variables standardized per minute revealed almost certain very large decreases in the 6 vs. 6 vs. the 3 vs. 3 format in the variables of CB (‐67.9%, [‐75.3;‐55.9]), LB (‐66.0%, [‐73.9;‐55.7]), RB (‐65.6%, [‐74.8;‐ 53.1]) and S (‐87.6%, [‐93.1;‐77.7]). The results of this study suggest that both formats of play are too noisy to be reproducible. The 3 vs. 3 format largely increased the number of individual technical actions.

Key words

  • soccer
  • reproducibility
  • drill‐based tasks
  • sports training
Accesso libero

Monitoring Changes Over a Training Macrocycle in Regional Age‐Group Swimmers

Pubblicato online: 18 Oct 2019
Pagine: 213 - 223

Astratto

Abstract

Our aim was to analyze physiological, kinematical and performance changes induced by swimming training in regional age‐group athletes. Subjects (15.7 ± 2.2 years old) performed a 4 x 50‐m front‐crawl test at maximal velocity (10 s rest interval) in weeks 2, 4, 9 and 12 of a 15‐week macrocycle. Descriptive statistics were used and the percentage of change and smallest worthwhile change (moderate, 0.6‐1.2, and large, > 1.2) were measured. Lactate concentration in the third, seventh and twelfth minute of recovery decreased significantly between weeks 2‐9 (14.1, 15.7 and 17.6%) and increased between weeks 9‐12 (18.2, 18.6 and 19.8%), with the HR presenting only trivial variations during the training period. Stroke length showed a large decrease in the first 50‐m trial between weeks 4‐9 (6.2%) and a large increase between weeks 9‐12 (3.1%). The stroke rate (in all 50‐m trials) increased significantly between weeks 4‐9 (3‐ 7%) and the stroke index had a moderate to large increase in the first and third 50‐m trial (3.6 and 7.1%, respectively) between weeks 9‐12. The overall time decreased by 1.1% between weeks 2‐12, being more evident after week 4. We concluded that physiological, kinematical and performance variables were affected by the period of training in regional age‐group swimmers.

Key words

  • macrocycle adaptations
  • longitudinal assessment
  • performance analysis
  • kinematics
Accesso libero

Effect of the French Contrast Method on Explosive Strength and Kinematic Parameters of the Triple Jump Among Female College Athletes

Pubblicato online: 18 Oct 2019
Pagine: 225 - 230

Astratto

Abstract

There are resistance training methods that result in strength, others that enhance hypertrophy and others that stimulate power. The training modality of contrast provides all of these benefits in one session. The concept of French Contrast training is based on a combination of complex and contrast methods. The idea is to use four exercises to induce physiological responses of the athlete and train along the force-speed curve. The primary purpose of the study was to investigate the impact of the French Contrast Method on explosive strength and kinematic parameters of the triple jump among female college athletes. Ten female college athletes from the Helwan University’s track and field team participated in this study. Participants were assessed before and after an 8-week training program for upper and lower body explosive strength. No significant differences were observed in anthropometric characteristics. Explosive strength variables (Sargent jump test, countermovement jump, and seated medicine ball throw) increased significantly and kinematic parameters of the triple jump improved. The results indicated that eight weeks of the French Contrast training can improve both explosive strength and kinematic parameters of the triple jump.

Key words

  • French Contrast Method
  • explosive strength
  • kinematic parameters
  • triple jump
Accesso libero

Trends of Goal Scoring Patterns in Soccer: A Retrospective Analysis of Five Successive FIFA World Cup Tournaments

Pubblicato online: 18 Oct 2019
Pagine: 231 - 238

Astratto

Abstract

This study analysed the 795 goals scored during a total of 320 matches played in five successive FIFA World Cup tournaments (1998–2014). Data were obtained through YouTube videos and analysed by means of Longomatch software. The variables analysed included the number of goals scored per half (45‐min period), per 15‐min period, and per 30‐min period of extra time, goal scoring zones, goals scored by substitutes, types of goals scored, and goals scored according to the playing position. With regard to 15‐min period analysis, most goals were scored between the 76th and 90th minutes (24.7%) of the game in all five World Cup competitions. Chi‐square analyses showed no significant (p > 0.05) differences in the frequency of goal scoring patterns per 45‐min and 15‐min periods in the five World Cup tournaments. Most goals were scored from inside the goal (23.8%) and penalty (14.6%) areas. The greatest number of goals was scored by strikers (54.2%), followed by midfielders (33.3%) and defenders (2.3%). These findings provide practical implications for improving goal‐scoring performance in soccer.

Key words

  • soccer
  • tactics
  • video analysis
  • goals
  • performance
Accesso libero

Post‐Activation Potentiation: Is there an Optimal Training Volume and Intensity to Induce Improvements in Vertical Jump Ability in Highly‐Trained Subjects?

Pubblicato online: 18 Oct 2019
Pagine: 239 - 247

Astratto

Abstract

The aim of this study was to compare the acute effects of performing half squats (HSs) with different loading intensities (1, 3, and 5 repetitions maximum [RM], and 60% 1RM) and a different number of sets (1, 2, and 3) on the countermovement jump (CMJ) performance of 18 highly‐trained male subjects. Participants were submitted to four experimental conditions (1RM, 3RM, 5RM, and 60% 1RM) in randomized order. The CMJ was assessed before and after each set. Differences in CMJ performance between the distinct experimental conditions and individual responses in CMJ performance induced by the different protocols were analyzed via the magnitude‐based inference method. Overall, significant improvements were detected in individual CMJ heights after each activation protocol. It can be concluded that the use of 1 to 3 sets of HSs performed at moderate‐to‐high loads may be an effective strategy to improve jump performance in highly‐trained subjects. Nonetheless, despite the high efficiency of the protocols tested here, coaches and researchers are strongly encouraged to perform individualized assessments within the proposed range of loads and sets, to find optimal and tailored post‐activation potentiation protocols.

Key words

  • warm‐up
  • vertical jump
  • muscle power
  • conditioning activity
  • athletic performance
  • strength training
Accesso libero

Combined Small‐Sided Game and High‐Intensity Interval Training in Soccer Players: The Effect of Exercise Order

Pubblicato online: 18 Oct 2019
Pagine: 249 - 257

Astratto

Abstract

The aim of the present study was to compare combined small‐sided game (SSG) and high‐intensity interval training (HIT) with different order. Twenty‐one semi‐professional soccer players were divided into two groups: SSG+HIT (n = 10) and HIT+SSG (n = 11), and underwent similar four‐week training programs. Players completed the 30‐15 Intermittent Fitness Test (30‐15IFT) before and after the experiment; maximum speed (VIFT) was recorded. During the experiment, seven sessions of SSG (3 vs 3) and HIT (15ʺ‐15ʺ with 95‐100% VIFT) were implemented. Weekly accumulated training loads for both groups during the experiment were similar. Moderate improvements in VIFT were observed in both SSG+HIT (+6.2%, 90% confidence limits, [CL] 4.6; 7.7 and Effect Size, [ES] +0.96) and HIT+SSG (+6.9%, 90% CL 4.6; 9.3 and ES +0.97) groups. Between‐group difference in changes of VIFT was trivial (+0.7%, 90% CL ‐1.8; 3.3 and ES +0.11). Combining SSG and HIT in different order elicited the same enhancement in high‐intensity intermittent performance in soccer players.

Key words

  • high‐intensity intermittent performance
  • internal training load
  • 30‐15 Intermittent Fitness Test
  • Association Football
  • SSGs
  • session rating of perceived exertion
Accesso libero

Player Load and Metabolic Power Dynamics as Load Quantifiers in Soccer

Pubblicato online: 18 Oct 2019
Pagine: 259 - 269

Astratto

Abstract

There has recently been an increase in quantification and objective analysis of soccer performance due to improvements in technology using load indexes such as Player Load (PL) and Metabolic Power (MP). The objectives of this study were: (1) to describe the performance of PL and MP in competition according to the specific role, match‐to‐ match variation, periods of play, game location and match status according to game periods, and (2) to analyze the relationship between both indexes. Twenty‐one national‐level soccer players were distributed in the following specific positional roles: external defenders (ED) (n = 4), central defenders (CD) (n = 4), midfielders (M) (n = 5), external midfielders (EM) (n = 4) and attackers (A) (n = 4). A total of 12 matches played by a Spanish Third Division team during the 2016/2017 season were analyzed. WIMU PROTM inertial devices (RealTrack System, Almeria, Spain) were used for recording the data. The main results were: (1) a performance reduction in both variables over the course of match time, (2) significant differences in both variables based on the specific position, (3) differences in physical demands during the season matches, (4) winning during a game period and the condition of being the visitor team provoked higher demands, and (5) a high correlation between both variables in soccer. In conclusion, different contextual variables influence the external load demands; both indexes are related so they could be used for external load quantification, and it is necessary to analyze physical demands of the competition for a specific and individualized load design in training sessions.

Key words

  • physical demands
  • external load
  • inertial devices
  • team sports
  • performance
  • contextual variables
Accesso libero

Post-Activation Potentiation on Squat Jump Following Two Different Protocols: Traditional vs. Inertial Flywheel

Pubblicato online: 18 Oct 2019
Pagine: 271 - 281

Astratto

Abstract

Post‐activation potentiation (PAP) has been defined as a major enhancement of muscular performance following a preload stimulus. The eccentric actions seem to cause a potentiating effect on subsequent explosive exercises. The aim of this study was to determine whether a protocol of squat exercise using an inertial flywheel could have a potentiating effect on jump performance. Sixteen physically active volunteers participated in the study (age: 21.8 ± 2.7 years; body mass index: 23.6 ± 3). All participants completed two different protocols on separate days: a Traditional Protocol (using a half squat with a guided barbell) and an Inertial Flywheel Protocol (using a half squat with an inertial flywheel). Both protocols were similar and consisted of 3 x 6 reps at the load that maximized power, with a 3‐minute rest interval between sets. The squat jump (SJ) was measured by a contact platform at baseline, and four, eight and twelve minutes after the PAP stimulus. A two‐way ANOVA with repeated measures was performed to analyze significant differences over time. There were significant increases of SJ height (p = 0.004, d = 0.665), velocity (p = 0.003, d = 0.688) and power (p = 0.004, d = 0.682) from baseline after the inertial flywheel protocol. A significant interaction effect (time x protocol) was observed, showing that the inertial flywheel protocol had a potentiating effect on the jump performance compared to the traditional protocol, more specifically at 4 and 8 minutes after the PAP stimulus. In conclusion, the inertial flywheel protocol showed a potentiating effect on the squat jump performance, thus this pre‐ conditioning activity could be useful during the warm‐up before the competition.

Key words

  • muscle pre‐activation
  • eccentric overload
  • conical pulley
  • half squat
  • explosive movement
Accesso libero

Physical Performance Differences Between Starter and Non‐Starter Players During Professional Soccer Friendly Matches

Pubblicato online: 18 Oct 2019
Pagine: 283 - 291

Astratto

Abstract

The aim of this study was to investigate the physical performance differences between players that started (i.e. starters, ≥65 minutes played) and those that were substituted into (i.e. non‐starter) soccer friendly matches. Fourteen professional players (age: 23.2 ± 2.7 years, body height: 178 ± 6 cm, body mass: 73.2 ± 6.9 kg) took part in this study. Twenty, physical performance‐related match variables (e.g. distance covered at different intensities, accelerations and decelerations, player load, maximal running speed, exertion index, work‐to‐rest ratio and rating of perceived exertion) were collected during two matches. Results were analysed using effect sizes (ES) and magnitude based inferences. Compared to starters, non‐starters covered greater match distance within the following intensity categories: >3.3≤4.2m/s (very likely), >4.2≤5 m/s (likely) and >5≤6.9 m/s (likely). In contrast, similar match average acceleration and deceleration values were identified for starters and non‐starters (trivial). Indicators of workloads including player loads (very likely), the exertion index (very likely), and the work–to‐rest ratio (very likely) were greater, while self‐ reported ratings of perceived exertion were lower (likely) for non‐starters compared to starters. The current study demonstrates that substantial physical performance differences during friendly soccer matches exist between starters and non‐starters. Identification of these differences enables coaches and analysts to potentially prescribe optimal training loads and microcycles based upon player’s match starting status.

Key words

  • acceleration
  • competition
  • measurement
  • performance
  • team sport
27 Articoli

Section I - Kinesiology

Accesso libero

Application of Virtual Reality in Competitive Athletes – A Review

Pubblicato online: 18 Oct 2019
Pagine: 5 - 16

Astratto

Abstract

The purpose of this study was to determine the state of the art in the area of virtual reality in competitive athletes of different levels of expertise in various disciplines and point the areas of its application. Articles published before August 2018 were considered in our review. The PubMed, SCOPUS, SportDiscus and Medline databases were searched. A combination of the following search terms was used: virtual reality, virtual environment, virtual system, athletes, sports, physical training, sport performance, physical exercises. Studies involved healthy competitive athletes. A total of 18 articles met the inclusion criteria. There were three areas of application of virtual reality to sport: performance analysis, simulation improvement and virtual training. Competitive athletes were mostly examined in a semi‐immersive setting. In conclusion, virtual reality seems to play a marginal role in competitive athletes’ training. Due to the fact that virtual reality interventions bring significant improvements in clinical research, well‐designed randomized control trials with detailed virtual training programmes are required in the future. Practically, virtual reality is effectively and commonly used to analyse performance in competitive athletes. There is still a need of creating fully interactive VR, where athletes will be able to cooperate with a virtual partner and influence the environment.

Key words

  • sport simulation
  • immersion
  • training
  • athletic performance
Accesso libero

Reaction to a Visual Stimulus: Anticipation with Steady and Dynamic Contractions

Pubblicato online: 18 Oct 2019
Pagine: 17 - 27

Astratto

Abstract

Reacting fast to visual stimuli is important for many activities of daily living and sports. It remains unknown whether the strategy used during the anticipatory period influences the speed of the reaction. The purpose of this study was to determine if reaction time (RT) differs following a steady and a dynamic anticipatory strategy. Twenty‐two young adults (21.0 ± 2.2 yrs, 13 women) participated in this study. Participants performed 15 trials of a reaction time task with ankle dorsiflexion using a steady (steady force at 15% MVC) and a dynamic (oscillating force from 10‐20% MVC) anticipatory strategy. We recorded primary agonist muscle (tibialis anterior; TA) electromyographic (EMG) activity. We quantified RT as the time interval from the onset of the stimulus to the onset of force. We found that a dynamic anticipatory strategy, compared to the steady anticipatory strategy, resulted in a longer RT (p = 0.04). We classified trials of the dynamic condition based on the level and direction of anticipatory force at the moment of the response. We found that RT was longer during the middle descending relative to the middle ascending and the steady conditions (p < 0.01). All together, these results suggest that RT is longer when preceded by a dynamic anticipatory strategy. Specifically, the longer RT is a consequence of the variable direction of force at which the response can occur, which challenges the motor planning process.

Key words

  • reaction time
  • anticipation
  • steady contraction
  • sinusoidal contraction
Accesso libero

Differences in Mechanical Midsole Characteristics of Running Shoes Do Not Influence Physiological Variables in Aerobic and Anaerobic Running

Pubblicato online: 18 Oct 2019
Pagine: 29 - 38

Astratto

Abstract

The purpose of this study was to determine the influence of footwear stiffness and energy loss on oxygen uptake and heart rate in athletes running under aerobic and anaerobic conditions. Four footwear conditions with identical outsoles, insoles, upper materials, but different mechanical properties regarding polyurethane midsole materials were investigated. Respective midsole material characteristics were selected to represent a wide range of running shoes. The test procedure for eighteen well‐trained male runners was divided into three treadmill testing sessions: an incremental ramp protocol to estimate the individual ventilatory threshold (day 1), a test with 6‐minute stages in each shoe at 70% (aerobic, day 2) and 102% (anaerobic, day 3) of the participant’s ventilatory threshold. For oxygen uptake and the heart rate, no significant differences between footwear conditions were found for either running condition. Furthermore, no significant relationships between physiological variables and mechanical midsole characteristics were found. The wide range of significant stiffness differences in the rearfoot (52.7 N/mm) and forefoot areas (50.7 N/mm), as well as significant differences of the shoe midsole material energy loss in the rearfoot (18.8%) and forefoot areas (10.7%) were too low to influence physiological variables significantly when running below and slightly above the ventilatory threshold. It seems that shoe mass and shoe comfort can influence physiological variables more than the mechanical midsole characteristics of stiffness and energy loss. These results may have practical implications for shoe manufacturers, coaches, and athletes, alike.

Key words

  • footwear
  • midsole stiffness
  • energy loss
  • running
  • oxygen uptake
  • heart rate
Accesso libero

The Relationship Between Pistol Olympic Shooting Performance, Handgrip and Shoulder Abduction Strength

Pubblicato online: 18 Oct 2019
Pagine: 39 - 46

Astratto

Abstract

The ability to stabilize the gun, a crucial factor for performance in air pistol Olympic shooting, is thought to be strongly related to the muscular work of the shooter´s shoulder and forearm. The objective of the present study was to confirm this relationship by analysing the influence of maximal finger flexor forces and maximal isometric shoulder force on performance in female air pistol shooting. Twenty‐three female pistol shooters participated in the study. Handgrip and shoulder force data were recorded under competition conditions, during the official training time of national Spanish championships on the day previous to the competition and at the official training stands. Performance was measured as the total score of 40 shots at competition. Linear regressions between performance and age, weight, height, training experience, body mass index (BMI), mean and maximal finger flexor and shoulder forces were calculated. Significant correlations were found between performance and a) training hours b) peak finger flexor force relative to the BMI, and c) peak isometric force of the shoulder abduction relative to the BMI. The study concludes that there is a statistically significant correlation between performance and muscular forces exerted by the athletes relative to their BMI. Appropriate muscular strength training programs are therefore necessary in female air pistol Olympic shooting.

Key words

  • score
  • deltoid force
  • dynamometer
  • BMI
  • performance
Accesso libero

Is Test Standardization Important when Arm and Leg Muscle Mechanical Properties are Assessed Through the Force‐Velocity Relationship?

Pubblicato online: 18 Oct 2019
Pagine: 47 - 58

Astratto

Abstract

The force‐velocity (F‐V) relationship observed in multi‐joint tasks proved to be strong and approximately linear. Recent studies showed that mechanical properties of muscles: force (F), velocity (V) and power (P) could be assessed through the F‐V relationship although the testing methods have not been standardized. The aim of the present study was to evaluate and compare F‐V relationships assessed from two tests performed on a modified Smith machine that standardizes kinematics of the movement pattern. Fifteen participants were tested on the maximum performance bench press throws and squat jumps performed against a variety of different loads. In addition, their strength properties were assessed through maximum isometric force (Fiso) and one repetition maximum (1 RM). The observed individual F‐V relationships were exceptionally strong and approximately linear (r = 0.98 for bench press throws; r = 0.99 for squat jumps). F‐V relationship parameter depicting maximum force (F0) revealed high correlations with both Fiso and 1 RM indicating high concurrent validity (p < 0.01). However, the generalizability of F‐V relationship parameters depicting maximum force (F0), velocity (V0) and power (P0) of the tested muscle groups was inconsistent and on average low (i.e. F0; r = ‐0.24) to moderate (i.e. V0 and P0; r = 0.54 and r = 0.64, respectively; both p < 0.05). We concluded that the F‐V relationship could be used for the assessment of arm and leg muscle mechanical properties when standard tests are applied, since the typical outcome is an exceptionally strong and linear F‐V relationship, as well as high concurrent validity of its parameters. However, muscle mechanical properties could be only partially generalized across different tests and muscles.

Key words

  • generalizability
  • concurrent validity
  • parameter
  • power
  • load
Accesso libero

Regulation of Stride Length During the Approach Run in the 400‐M Hurdles

Pubblicato online: 18 Oct 2019
Pagine: 59 - 67

Astratto

Abstract

This research aims to clarify the stride adjustment in the approach of the 400‐m hurdles, and to examine the relationship with 400‐m hurdle performance. Seven male 400‐m hurdlers volunteered for this study. Participants ran three times from the start to the second hurdle. The standard deviation of toe‐hurdle distance and standard deviation of stride length at each step from the start to the first hurdle were calculated. The maximum value of the standard deviation of toe‐hurdle distance was defined as the position at which the athlete starts stride adjustment. The relationships between each variable, 400‐m hurdle personal best, and the ratio of 400‐m hurdle personal best and 400‐m running personal best (400 m/400‐m hurdles) were examined. Results concluded that standard deviation of toe‐hurdle distance gradually increased after the start, reached the maximum value in the latter half of the approach section, and then decreased until the takeoff. Standard deviation of stride length increased significantly from 4 steps before the takeoff. From these trends, it was suggested that athletes seemed to start stride adjustment from the middle stage to the latter half of the approach by sensing stride error accumulation in the middle of the approach. The strides immediately before the takeoff were markedly involved in stride adjustment. Furthermore, the stride adjustment technique to reduce maximum accumulation error of stride evaluated in the approach section was considered associated with the smooth running of the entire 400‐m hurdle race.

Key words

  • hurdles
  • maximum accumulation error
  • stride length
  • standard deviation of toe‐hurdle distance
Accesso libero

Less Than One Millimeter Under the Great Toe is Enough to Change Balance Ability in Elite Women Handball Players

Pubblicato online: 18 Oct 2019
Pagine: 69 - 77

Astratto

Abstract

Team handball is a complex intermittent sport game, which requires several motor abilities and effective postural control. Objective evaluation of stabilometric variables may be interesting to assess and improve functional parameters by postural control management. The purpose of the study was to evaluate the effects of a small additional thickness placed under the great toe (TUGT) on the Centre of Pressure (CoP) parameters in elite women handball players. Fourteen elite women handball players voluntarily participated in this study. Two conditions were compared: TUGT 0 (control) and TUGT 0.8 mm; four variables were computed from the CoP displacements. A paired T‐test was performed for each variable. This study concludes that a low focal additional thickness placed under both great toes has an effect on the CoP measures used to assess postural control during an unperturbed stance. These results suggest that a low TUGT could contribute to a change in balance ability, and may be of clinical interest. This brings new perspectives in the management of athletes to prevent injury risk and optimize performance.

Key words

  • postural insoles
  • balance ability
  • toes

Section II - Exercise Physiology & Sports Medicine

Accesso libero

Relationships Between the Expression of the ACTN3 Gene and Explosive Power of Soccer Players

Pubblicato online: 18 Oct 2019
Pagine: 79 - 87

Astratto

Abstract

Muscle strength and maximal speed are factors determining athlete’s results during competition. Their association with ACTN3 gene activity has been documented. The purpose of this study was the analysis of ACTN3 gene expression during a 2 month training cycle of soccer players and its correlation with the countermovement jump (CMJ) and squat jump (SJ). The study group consisted of 22 soccer players (aged 17‐18). The study material included peripheral blood lymphocytes. The relative expression (RQ) of the ACTN3 gene was analyzed by qPCR and performed before and after the two‐month training cycle. Before the training cycle low expression levels of ACTN3 (median RQ = 0.95) were observed, yet after the training cycle they were elevated (median RQ = 1.98) ( p = 0.003). There was an increase in performance of both jumps: SJ (p = 0.020) and CMJ (p = 0.012) at the end of the training cycle. A simultaneous increase in the ACTN3 gene expression level and height in both jump tests was observed in 73% of athletes (p > 0.05). There were no significant relationships between the ACTN3 gene expression level and the results of the CMJ and SJ. However, explosive strength is a complex feature shaped by many different factors and it could be the reason why we did not observe correlations between these variables.

Key words

  • α‐actinin‐3 gene
  • soccer players
  • explosive power
  • squat jump
  • counter movement jump
Accesso libero

Cardiovascular and Perceived Effort in Different Head‐Out Water Exercises: Effect of Limbs’ Action and Resistance Equipment

Pubblicato online: 18 Oct 2019
Pagine: 89 - 97

Astratto

Abstract

The aim of this study was to compare the cardiovascular and perceived effort of head‐out water exercises selecting different limb strategies and using resistance equipment. Ten young women were randomly assigned to perform at 132 bpm during five minutes different head‐out aquatic exercises: (i) horizontal arms abduction (Ab); (ii) horizontal arms abduction with dumbbells (AbD); (iii) frontal kick (Fk); (iv) frontal kick with leggings (FkLeg), and; (v) aquatic skiing (Ski). Cardiovascular effort was measured by monitoring the heart rate, blood pressure and double product. Perceived effort was assessed by the Borg’s scale. Within‐routines comparison was computed using repeated‐ measures ANOVA followed‐up by the Bonferroni post‐hoc test. Considering the percentage of the maximal heart rate, participants reached 72.88 ± 12.90% in the FkLeg, 65.99 ± 10.91% in the Fk, 62.62 ± 7.20% in Ski, 57.27 ± 11.58% in AbD and 57.12 ± 12.09% in Ab. Comparing exercises, higher heart rates were observed in the FkLeg (140.40 bpm) than Ab (110.30 bpm) or AbD (110.00 bpm). Significant differences were found in the systolic blood pressure when compared to the Fk (120.60 mmHg) and Ab (104.50 mmHg). Double product was higher in the FkLeg (16990) showing a meaningful difference when compared to Ab (11608) or AbD (12001). The highest perceived effort was found in the FkLeg (15.80) with meaningful variations compared to Ab (11.70), the Fk (13.70) and Ski (10.40). Thus, different head‐ out water exercises result in different intensities. The actions by lower limbs promote a higher cardiovascular response, whereas the upper limbs actions trigger a lower exertion. Moreover, exercising the four limbs concurrently seems to be less intense than using only two limbs with an aid.

Key words

  • aquatic exercise
  • segmental action
  • buoyancy devices
  • heart rate
  • perceived exertion
Accesso libero

The Acute Effects of High‐Intensity Cycling Exercise on Arterial Stiffness in Adolescent Wrestlers

Pubblicato online: 18 Oct 2019
Pagine: 99 - 107

Astratto

Abstract

The aim of this study was to determine the acute effects of high‐intensity cycling exercise on the variables of carotid artery compliance, distensibility and beta stiffness index in elite adolescent wrestlers. The subjects were elite athletes competing in national, European and World Championships, who attended a training camp in the province of Kahramanmaras organized by the Turkish Centre for Olympic Preparation. The study sample comprised 31 male elite wrestlers with a mean age of 15.90 ± 0.87 years, body height of 165.97 ± 9.7 cm and body mass of 66.3 ± 18.45 kg. The arterial stiffness variables of the wrestlers were measured with high‐resolution Doppler ultrasonography before and 5 min after 30 s of high‐intensity cycling exercise (the Wingate Anaerobic Cycling test). The results showed a statistically significant correlation between mean power performance and carotid artery compliance at the 5th min after a single cycling sprint exercise (p < 0.05). No correlation was determined between peak power and the arterial stiffness variables (p > 0.05). The study results indicate that acute changes in arterial stiffness variables are associated with the performance level of high‐intensity cycling exercise in a group of elite adolescent wrestlers.

Key words

  • sprint performance
  • anaerobic exercise
  • arterial sclerosis
Accesso libero

Can Anthropometric Variables and Maturation Predict the Playing Position in Youth Basketball Players?

Pubblicato online: 18 Oct 2019
Pagine: 109 - 123

Astratto

Abstract

Anthropometric diagnoses predict the most appropriate on‐court position for a certain player and are important in the long‐term planning of basketball training programs. This study provides anthropometric characteristics and body composition profiles of Polish youth national team players (U‐14, U‐15, U‐16 and U‐18). The aim of this research was to determine the somatic characteristics of basketball players regarding particular on‐court positions. The sample population consisted of 109 elite basketball players, who played in national teams in four age categories: U‐14, U‐16, U‐18 U‐20. An analysis of the obtained results revealed differences between the younger (U‐14, U‐15 and U‐16) and older groups (U‐18 and U‐20) in terms of length, width and circumference measurements and body mass (3.6–9.3%), as well as subcutaneous fat measured by the skinfold thickness method (14.3–33.7%). ANCOVA with maturity offset as the covariate variable showed differences in body height (p < 0.05, R2 = 0.74) and the arm span (p < 0.05, R2 = 0.87) between each playing position; the somatic measurements were greater for centers than for forwards and guards, and the measurements were greater for forwards than for guards. The somatic feature measurements also increased linearly with age. We can conclude that the arm span and body height are two major somatic factors that can predict center and guard playing positions for national team basketball players in all age categories from U‐14 to U‐20.

Key words

  • anthropometric indicators
  • somatotype
  • peak height velocity
  • professional sport
  • selection
  • basketball players
Accesso libero

Practical Use of the Navigate Pain Application for the Assessment of the Area, Location, and Frequency of the Pain Location in Young Soccer Goalkeepers

Pubblicato online: 18 Oct 2019
Pagine: 125 - 135

Astratto

Abstract

Next to winning, minimizing injuries during training and matches is one of the primary goals of professional team sports games. Soreness and pain can be early indicators and risk factors for acute or long‐term injuries. Monitoring pain intensity and duration, as well as potential sources, are useful for planning practices and can be effective means for preventing injury. The aim of this study was to assess the areas and locations of pain in young soccer goalkeepers during a training camp, and to differentiate the area and frequency between pain arising from the muscles (MP), joints (JP), or as a result of an impact (IP). Recordings of the MP, JP, and IP location along with the area were performed using digital body mapping software (Navigate Pain Android app, Aalborg University, Denmark) installed on a tablet personal computer at the end of each training day across a 5‐day training camp. There was a significant difference in the area between the three types of pain (p < 0.001). The post hoc analysis revealed statistically significant differences between the pixel areas of IP versus JP (p < 0.001), IP versus MP (p < 0.001), and JP versus MP (p < 0.001). There was no significant time‐effect for the IP area between 1‐5 days of training (p = 0.610), neither for MP (p = 0.118) or JP (p = 0.797) and no significant difference for all three pain areas between the front and the back side of the body. The body regions most often reported for MP were thighs, while for JP they were groin and hips, and for IP the hips, shoulders, and forearms were most frequently indicated. This is the first study to map and report the pain distribution associated with training across a 5‐day training camp in soccer goalkeepers, and these findings emphasize the value of using digital pain drawings clinically as well as for monitoring the health status of soccer players.

Key words

  • pain
  • navigate pain
  • soccer
  • goalkeepers training
Accesso libero

International Standards for the 3‐Minute Burpee Test: High‐ Intensity Motor Performance

Pubblicato online: 18 Oct 2019
Pagine: 137 - 147

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Abstract

The aim of this study was to develop international standards for evaluating strength endurance with the use of the 3‐Minute Burpee Test. The results of 3862 women (Poland – 2502, Great Britain – 500, Hungary – 412, Serbia – 448) and 5971 men (Poland – 4517, Great Britain – 500, Hungary – 451, Serbia – 503) aged 18‐25 (mean age of 20.36 ± 0.94 and 20.05 ± 1.25 y, respectively) were collated between 2004 and 2018. The students’ strength endurance was evaluated in the 3‐Minute Burpee Test. The results were expressed on a uniform scale with the 3‐sigma rule which was used to develop the T‐score scale for the 3‐Minute Burpee Test. Men completed 56.69 cycles/3 min and women – 48.84/3 min on average. The best male participant completed 82 burpees, and the best female participant – 73 burpees. The majority of male and female participants (66.71% and 68.18%, respectively) were characterized by average strength endurance in the 3‐Minute Burpee Test (range of scores: 47‐66 and 37‐60 cycles/3 min, respectively). Very good strength endurance (76‐85 and 72‐83 cycles/3 min, respectively) was noted in the smallest percentage of male and female participants (0.52% and 0.26%, respectively). Similar studies should be carried out in other countries and in different age groups to develop objective international classification standards for variously‐aged individuals.

Key words

  • strength endurance
  • extreme effort
  • 3‐MBT
  • norms
Accesso libero

Effect of Virtual Reality‐Based Rehabilitation on Physical Fitness in Patients with Chronic Obstructive Pulmonary Disease

Pubblicato online: 18 Oct 2019
Pagine: 149 - 157

Astratto

Abstract

The aim of the study was to evaluate the effects of rehabilitation in patients with chronic obstructive pulmonary disease (COPD) using the Kinect system during stationary rehabilitation. The study included 68 patients with COPD (35 men, 33 women, mean age 61.3 ± 3.7). The subjects were randomly assigned to one of the two experimental groups described below. Group I included 34 patients – non‐participants in Kinect training. Group II included 34 patients – participants in Kinect training. In all patients before and after rehabilitation physical fitness was assessed using the Senior Fitness Test (SFT). The Xbox 360 and Kinect motion sensor were used to carry out virtual reality training. In group I, statistically significant improvements in SFT performance were observed. Patients in group II also showed statistically significant improvement in physical fitness in all attempts of the SFT. Virtual rehabilitation training in patients with COPD seems to be a practical and beneficial intervention capable of enhancing mobility and physical fitness.

Key words

  • virtual rehabilitation
  • COPD
  • physical fitness
  • virtual reality
  • pulmonary rehabilitation
Accesso libero

Predicting Competition Performance in Short Trail Running Races with Lactate Thresholds

Pubblicato online: 18 Oct 2019
Pagine: 159 - 167

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Abstract

Trail running is a popular sport, yet factors related to performance are still not fully understood. Lactate thresholds have been thoroughly investigated in road running and correlate strongly with race performance, but to date few data are available about the value in trail running performance prediction. We examined 25 trail runners (age 31.2 ± 5.1 years, BMI 22.2 ± 1.82 kg/m2) with an initial graded exercise test for measurement of VO2max (59.5 ± 5.2 ml.kg‐1.min‐ 1) and lactate thresholds (LT): LTAET (LT aerobic) 1.03 ± 0.59 mmol/l; 11.2 ± 1.1 km/h), IAT (individual lactate threshold) (2.53 ± 0.59 mmol/l; 15.4 ± 1.6 km/h) and LT4 (lactate threshold at 4 mmol/l) (16.2 ± 1.9 km/h). All runners subsequently participated in a 31.1 km XS trail race and 9 runners in a 21 km XXS trail race. Race performance times correlated negatively with the XS trail run (LTAET: r = ‐0.65, p < 0.01; LT4: r = ‐0.87, p < 0.01; IAT: r = ‐0.84, p < 0.01) and regression analysis showed that race performance could be predicted by: LT4: ‐324.15×LT4+13195.23 (R2 = .753, F1,23 = 70.02, p < 0.01). A subgroup analysis showed higher correlations with race performance for slower than faster runners. No correlations were found with the XXS race. Lactate thresholds can be of value in predicting trail race performance and help in designing training plans.

Key words

  • anaerobic threshold
  • exercise test
  • exercise
  • endurance
  • athletic performance
Accesso libero

Effects of Terbutaline Sulfate on Physiological and Biomechanical as Well as Perceived Exertion in Healthy Active Athletes: A Pilot Study

Pubblicato online: 18 Oct 2019
Pagine: 169 - 178

Astratto

Abstract

This study aimed to investigate the effects of beta2‐agonist terbutaline sulfate (TER) at a supra‐therapeutic dose (8 mg) on aerobic exercise performance. Twelve (6 females and 6 males) amateur athletes familiarized with all experimental procedures had their anthropometric data obtained on day 1. On days 2 and 3 either 8 mg of TER or a placebo (PLA) was administered orally (double‐blind manner) to participants who had rested for 3 h prior to aerobic exercise performance 20 m multistage fitness test (MSFT)]. This test was used to predict maximal oxygen uptake (VO2max) and velocity at which VO2max occurs (vVO2max). The Borg rating of perceived exertion (RPE), cardiovascular variables [heart rate (HR) and blood pressure (BP)] and blood glucose concentration [BGC] were obtained 15 min pre‐ and immediately post‐MSFT. Significant mean group differences were reported between PLA and TER groups (p < 0.05), respectively, in the RPE (15.6 ± 1.2 vs. 17.3 ± 1.5 a.u.), maximum heart rate (HRmax: 191.2 ± 7.1 vs. 197.2 ± 8.6 bpm) and BGC (118.4 ± 18.3 vs. 141.2 ± 15.8 mg/dL) post‐MSFT. The main effect of gender (male vs. female) in TER and PLA groups (p< 0.05) was observed, with higher estimated VO2max, vVO2max, HRmax and a lower mean HR pre‐test in male than female athletes. For these reasons, the inclusion of TER in the Prohibited List should be re‐discussed because of the lack of ergogenic effects.

Key words

  • β2‐agonist
  • doping
  • blood glucose concentration
  • blood arterial pressures
  • heart rate
Accesso libero

No Pain, No Gain? Prevalence, Location, Context, and Coping Strategies with Regard to Pain Among Young German Elite Basketball Players

Pubblicato online: 18 Oct 2019
Pagine: 179 - 189

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Abstract

Pain among young athletes requires special attention given that symptoms occur during the ongoing development of the conditional, and in particular, the motor capacities, and while the musculoskeletal system is in a continuous process of growth. The purpose of this study was to evaluate prevalence, location, context, and coping strategies regarding pain among young athletes. We chose survey data of young elite athletes from the highest level national basketball leagues in Germany, as this meant that health implications may be observed earlier and in a more pronounced manner. The German ‘Adolescents’ and Children’s Health in Elite Basketball study’ (ACHE study), a quantitative survey, was conducted between April and June 2016. Analyses were based on elite basketball players between 13 and 19 years of age from 46 German teams (n = 182). Constant, and to some extent severe pain, was part of daily life of young elite basketball players: eight out of ten players in the highest German leagues suffered from pain at the time of the survey. Knee, leg, and back pain occurred most frequently. For most players, occasional or frequent consumption of analgesics was the norm, in some cases these were also taken “prophylactically”. The consumption of multiple pharmaceutical substances, especially of cyclooxygenase inhibitors such as ibuprofen and diclofenac, is widespread among adolescent elite basketball players. Physicians involved in treating these athletes should address pain and its management preemptively. Coaches, sporting organizations and parents should be involved in this process from an early stage.

Key words

  • pain
  • athletes
  • adolescent
  • analgesics
  • basketball

Section III - Sports Training

Accesso libero

Analysis of Successful Offensive Play Patterns by the Spanish Soccer Team

Pubblicato online: 18 Oct 2019
Pagine: 191 - 200

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Abstract

Victory is the ultimate aim in soccer and therefore when a team wins an elite European or world championship, attempts will invariably be made to emulate the winning team’s style of play. In this study, we performed an in‐depth analysis of play by the Spanish soccer team during the 2012 UEFA European Championship, where it was crowned champion. Using observational methodology and T‐pattern analysis, we identified hidden patterns of play that ended in a goal for the Spanish team. A generalizability coefficient (e2) of 0.986 demonstrated that the offensive patterns detected are robust and highly generalizable. These patterns were formed by technical actions consisting of ball control and pass, with alternations between short and long passes, in the central area of the rival pitch, with use of both wings to achieve width of play and prioritization of width over depth of play. We also found patterns showing that goals and shots at goal were made on a ball delivered from the opposite direction to the shot and were not preceded by a technical action.

Key words

  • team sport
  • performance
  • game analysis
  • tactics
Accesso libero

Variability of Technical Actions During Small‐Sided Games in Young Soccer Players

Pubblicato online: 18 Oct 2019
Pagine: 201 - 212

Astratto

Abstract

The purpose of this study was three‐fold: (i) to test the between‐sessions variability of 3 vs. 3 and 6 vs. 6 formats in under‐11 players, (ii) to assess the within‐session variability of 3 vs. 3 and 6 vs. 6 formats, and (iii) to investigate the variations of technical actions between formats. Sixteen soccer players (10.1 ± 0.3 years old) participated in this study. Both formats of play were played twice within an interval of one week to test the between‐session variability and the variables of conquered balls (CBs), received balls (RBs), lost balls (LBs), attacking balls/passes (ABs) and shots (Ss) were analyzed using the Performance Assessment in Team Sports instrument in all matches. Moderate variations on the sum of sets during the 3 vs. 3 and 6 vs. 6 formats were observed in all variables. Considering the variations of technical actions made between sets in the 3 vs. 3 format, likely moderate increases were found in set 2 vs. 1 in terms of RB (37.5%, [‐2.7;94.2]), and likely small decreases were found in set 3 vs. 2 for the same variable (‐18.3%, [‐37.8;7.3]). In the 6 vs. 6 format, only possibly small increases were found for set 3 vs. 1 in S (22.5%, [‐7.0;61.3]). Generally (sum of sets), the variables standardized per minute revealed almost certain very large decreases in the 6 vs. 6 vs. the 3 vs. 3 format in the variables of CB (‐67.9%, [‐75.3;‐55.9]), LB (‐66.0%, [‐73.9;‐55.7]), RB (‐65.6%, [‐74.8;‐ 53.1]) and S (‐87.6%, [‐93.1;‐77.7]). The results of this study suggest that both formats of play are too noisy to be reproducible. The 3 vs. 3 format largely increased the number of individual technical actions.

Key words

  • soccer
  • reproducibility
  • drill‐based tasks
  • sports training
Accesso libero

Monitoring Changes Over a Training Macrocycle in Regional Age‐Group Swimmers

Pubblicato online: 18 Oct 2019
Pagine: 213 - 223

Astratto

Abstract

Our aim was to analyze physiological, kinematical and performance changes induced by swimming training in regional age‐group athletes. Subjects (15.7 ± 2.2 years old) performed a 4 x 50‐m front‐crawl test at maximal velocity (10 s rest interval) in weeks 2, 4, 9 and 12 of a 15‐week macrocycle. Descriptive statistics were used and the percentage of change and smallest worthwhile change (moderate, 0.6‐1.2, and large, > 1.2) were measured. Lactate concentration in the third, seventh and twelfth minute of recovery decreased significantly between weeks 2‐9 (14.1, 15.7 and 17.6%) and increased between weeks 9‐12 (18.2, 18.6 and 19.8%), with the HR presenting only trivial variations during the training period. Stroke length showed a large decrease in the first 50‐m trial between weeks 4‐9 (6.2%) and a large increase between weeks 9‐12 (3.1%). The stroke rate (in all 50‐m trials) increased significantly between weeks 4‐9 (3‐ 7%) and the stroke index had a moderate to large increase in the first and third 50‐m trial (3.6 and 7.1%, respectively) between weeks 9‐12. The overall time decreased by 1.1% between weeks 2‐12, being more evident after week 4. We concluded that physiological, kinematical and performance variables were affected by the period of training in regional age‐group swimmers.

Key words

  • macrocycle adaptations
  • longitudinal assessment
  • performance analysis
  • kinematics
Accesso libero

Effect of the French Contrast Method on Explosive Strength and Kinematic Parameters of the Triple Jump Among Female College Athletes

Pubblicato online: 18 Oct 2019
Pagine: 225 - 230

Astratto

Abstract

There are resistance training methods that result in strength, others that enhance hypertrophy and others that stimulate power. The training modality of contrast provides all of these benefits in one session. The concept of French Contrast training is based on a combination of complex and contrast methods. The idea is to use four exercises to induce physiological responses of the athlete and train along the force-speed curve. The primary purpose of the study was to investigate the impact of the French Contrast Method on explosive strength and kinematic parameters of the triple jump among female college athletes. Ten female college athletes from the Helwan University’s track and field team participated in this study. Participants were assessed before and after an 8-week training program for upper and lower body explosive strength. No significant differences were observed in anthropometric characteristics. Explosive strength variables (Sargent jump test, countermovement jump, and seated medicine ball throw) increased significantly and kinematic parameters of the triple jump improved. The results indicated that eight weeks of the French Contrast training can improve both explosive strength and kinematic parameters of the triple jump.

Key words

  • French Contrast Method
  • explosive strength
  • kinematic parameters
  • triple jump
Accesso libero

Trends of Goal Scoring Patterns in Soccer: A Retrospective Analysis of Five Successive FIFA World Cup Tournaments

Pubblicato online: 18 Oct 2019
Pagine: 231 - 238

Astratto

Abstract

This study analysed the 795 goals scored during a total of 320 matches played in five successive FIFA World Cup tournaments (1998–2014). Data were obtained through YouTube videos and analysed by means of Longomatch software. The variables analysed included the number of goals scored per half (45‐min period), per 15‐min period, and per 30‐min period of extra time, goal scoring zones, goals scored by substitutes, types of goals scored, and goals scored according to the playing position. With regard to 15‐min period analysis, most goals were scored between the 76th and 90th minutes (24.7%) of the game in all five World Cup competitions. Chi‐square analyses showed no significant (p > 0.05) differences in the frequency of goal scoring patterns per 45‐min and 15‐min periods in the five World Cup tournaments. Most goals were scored from inside the goal (23.8%) and penalty (14.6%) areas. The greatest number of goals was scored by strikers (54.2%), followed by midfielders (33.3%) and defenders (2.3%). These findings provide practical implications for improving goal‐scoring performance in soccer.

Key words

  • soccer
  • tactics
  • video analysis
  • goals
  • performance
Accesso libero

Post‐Activation Potentiation: Is there an Optimal Training Volume and Intensity to Induce Improvements in Vertical Jump Ability in Highly‐Trained Subjects?

Pubblicato online: 18 Oct 2019
Pagine: 239 - 247

Astratto

Abstract

The aim of this study was to compare the acute effects of performing half squats (HSs) with different loading intensities (1, 3, and 5 repetitions maximum [RM], and 60% 1RM) and a different number of sets (1, 2, and 3) on the countermovement jump (CMJ) performance of 18 highly‐trained male subjects. Participants were submitted to four experimental conditions (1RM, 3RM, 5RM, and 60% 1RM) in randomized order. The CMJ was assessed before and after each set. Differences in CMJ performance between the distinct experimental conditions and individual responses in CMJ performance induced by the different protocols were analyzed via the magnitude‐based inference method. Overall, significant improvements were detected in individual CMJ heights after each activation protocol. It can be concluded that the use of 1 to 3 sets of HSs performed at moderate‐to‐high loads may be an effective strategy to improve jump performance in highly‐trained subjects. Nonetheless, despite the high efficiency of the protocols tested here, coaches and researchers are strongly encouraged to perform individualized assessments within the proposed range of loads and sets, to find optimal and tailored post‐activation potentiation protocols.

Key words

  • warm‐up
  • vertical jump
  • muscle power
  • conditioning activity
  • athletic performance
  • strength training
Accesso libero

Combined Small‐Sided Game and High‐Intensity Interval Training in Soccer Players: The Effect of Exercise Order

Pubblicato online: 18 Oct 2019
Pagine: 249 - 257

Astratto

Abstract

The aim of the present study was to compare combined small‐sided game (SSG) and high‐intensity interval training (HIT) with different order. Twenty‐one semi‐professional soccer players were divided into two groups: SSG+HIT (n = 10) and HIT+SSG (n = 11), and underwent similar four‐week training programs. Players completed the 30‐15 Intermittent Fitness Test (30‐15IFT) before and after the experiment; maximum speed (VIFT) was recorded. During the experiment, seven sessions of SSG (3 vs 3) and HIT (15ʺ‐15ʺ with 95‐100% VIFT) were implemented. Weekly accumulated training loads for both groups during the experiment were similar. Moderate improvements in VIFT were observed in both SSG+HIT (+6.2%, 90% confidence limits, [CL] 4.6; 7.7 and Effect Size, [ES] +0.96) and HIT+SSG (+6.9%, 90% CL 4.6; 9.3 and ES +0.97) groups. Between‐group difference in changes of VIFT was trivial (+0.7%, 90% CL ‐1.8; 3.3 and ES +0.11). Combining SSG and HIT in different order elicited the same enhancement in high‐intensity intermittent performance in soccer players.

Key words

  • high‐intensity intermittent performance
  • internal training load
  • 30‐15 Intermittent Fitness Test
  • Association Football
  • SSGs
  • session rating of perceived exertion
Accesso libero

Player Load and Metabolic Power Dynamics as Load Quantifiers in Soccer

Pubblicato online: 18 Oct 2019
Pagine: 259 - 269

Astratto

Abstract

There has recently been an increase in quantification and objective analysis of soccer performance due to improvements in technology using load indexes such as Player Load (PL) and Metabolic Power (MP). The objectives of this study were: (1) to describe the performance of PL and MP in competition according to the specific role, match‐to‐ match variation, periods of play, game location and match status according to game periods, and (2) to analyze the relationship between both indexes. Twenty‐one national‐level soccer players were distributed in the following specific positional roles: external defenders (ED) (n = 4), central defenders (CD) (n = 4), midfielders (M) (n = 5), external midfielders (EM) (n = 4) and attackers (A) (n = 4). A total of 12 matches played by a Spanish Third Division team during the 2016/2017 season were analyzed. WIMU PROTM inertial devices (RealTrack System, Almeria, Spain) were used for recording the data. The main results were: (1) a performance reduction in both variables over the course of match time, (2) significant differences in both variables based on the specific position, (3) differences in physical demands during the season matches, (4) winning during a game period and the condition of being the visitor team provoked higher demands, and (5) a high correlation between both variables in soccer. In conclusion, different contextual variables influence the external load demands; both indexes are related so they could be used for external load quantification, and it is necessary to analyze physical demands of the competition for a specific and individualized load design in training sessions.

Key words

  • physical demands
  • external load
  • inertial devices
  • team sports
  • performance
  • contextual variables
Accesso libero

Post-Activation Potentiation on Squat Jump Following Two Different Protocols: Traditional vs. Inertial Flywheel

Pubblicato online: 18 Oct 2019
Pagine: 271 - 281

Astratto

Abstract

Post‐activation potentiation (PAP) has been defined as a major enhancement of muscular performance following a preload stimulus. The eccentric actions seem to cause a potentiating effect on subsequent explosive exercises. The aim of this study was to determine whether a protocol of squat exercise using an inertial flywheel could have a potentiating effect on jump performance. Sixteen physically active volunteers participated in the study (age: 21.8 ± 2.7 years; body mass index: 23.6 ± 3). All participants completed two different protocols on separate days: a Traditional Protocol (using a half squat with a guided barbell) and an Inertial Flywheel Protocol (using a half squat with an inertial flywheel). Both protocols were similar and consisted of 3 x 6 reps at the load that maximized power, with a 3‐minute rest interval between sets. The squat jump (SJ) was measured by a contact platform at baseline, and four, eight and twelve minutes after the PAP stimulus. A two‐way ANOVA with repeated measures was performed to analyze significant differences over time. There were significant increases of SJ height (p = 0.004, d = 0.665), velocity (p = 0.003, d = 0.688) and power (p = 0.004, d = 0.682) from baseline after the inertial flywheel protocol. A significant interaction effect (time x protocol) was observed, showing that the inertial flywheel protocol had a potentiating effect on the jump performance compared to the traditional protocol, more specifically at 4 and 8 minutes after the PAP stimulus. In conclusion, the inertial flywheel protocol showed a potentiating effect on the squat jump performance, thus this pre‐ conditioning activity could be useful during the warm‐up before the competition.

Key words

  • muscle pre‐activation
  • eccentric overload
  • conical pulley
  • half squat
  • explosive movement
Accesso libero

Physical Performance Differences Between Starter and Non‐Starter Players During Professional Soccer Friendly Matches

Pubblicato online: 18 Oct 2019
Pagine: 283 - 291

Astratto

Abstract

The aim of this study was to investigate the physical performance differences between players that started (i.e. starters, ≥65 minutes played) and those that were substituted into (i.e. non‐starter) soccer friendly matches. Fourteen professional players (age: 23.2 ± 2.7 years, body height: 178 ± 6 cm, body mass: 73.2 ± 6.9 kg) took part in this study. Twenty, physical performance‐related match variables (e.g. distance covered at different intensities, accelerations and decelerations, player load, maximal running speed, exertion index, work‐to‐rest ratio and rating of perceived exertion) were collected during two matches. Results were analysed using effect sizes (ES) and magnitude based inferences. Compared to starters, non‐starters covered greater match distance within the following intensity categories: >3.3≤4.2m/s (very likely), >4.2≤5 m/s (likely) and >5≤6.9 m/s (likely). In contrast, similar match average acceleration and deceleration values were identified for starters and non‐starters (trivial). Indicators of workloads including player loads (very likely), the exertion index (very likely), and the work–to‐rest ratio (very likely) were greater, while self‐ reported ratings of perceived exertion were lower (likely) for non‐starters compared to starters. The current study demonstrates that substantial physical performance differences during friendly soccer matches exist between starters and non‐starters. Identification of these differences enables coaches and analysts to potentially prescribe optimal training loads and microcycles based upon player’s match starting status.

Key words

  • acceleration
  • competition
  • measurement
  • performance
  • team sport

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