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Aquatic Sports and Activities

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Presentation of the 1st International Symposium on Strength & Conditioning (ISSC 2011)

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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 61 (2018): Edizione 1 (March 2018)

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

24 Articoli

Section I – Kinesiology

Accesso libero

Functional Movements in Japanese Mini-Basketball Players

Pubblicato online: 23 Mar 2018
Pagine: 53 - 62

Astratto

Abstract

Functional movement screen (FMS) has been used to establish normative data and determine potential injury risk for young adults and athletes, but there are few data in elementary school-age children. The purpose of this study was to establish fundamental values for the FMS in elementary school-age mini-basketball players. Secondary purposes were to examine relationships between functional movement patterns and age, peak height velocity (PHV), and body mass index (BMI), and to compare functional movement patterns between boys and girls and between individuals with and without a history of injury. The mean composite FMS score was 16.5 ± 2.2 (16.5 ± 2.4 for boys, 16.5 ± 1.7 for girls). The composite FMS score was positively correlated with age (r = .312) and negatively correlated with the BMI (r = − .371). However, the FMS score was not correlated with PHV or with PHV age. The FMS score was not different between boys and girls or between individuals who reported a previous injury and those who did not. However, boys in the mini-basketball teams performed better than girls on the trunk stability push-up and rotary stability tests. Age and the body mass index were significantly associated with better and poorer functional movement, respectively.

Key words

  • functional movement screen
  • elementary school-aged children
  • injury risk
  • basketball players
  • youth
Accesso libero

The Effects of Cryotherapy on Knee Joint Position Sense and Force Production Sense in Healthy Individuals

Pubblicato online: 23 Mar 2018
Pagine: 39 - 51

Astratto

Abstract

The proprioceptive information received from mechanoreceptors is potentially responsible for controlling the joint position and force differentiation. However, it is unknown whether cryotherapy influences this complex mechanism. Previously reported results are not universally conclusive and sometimes even contradictory. The main objective of this study was to investigate the impact of local cryotherapy on knee joint position sense (JPS) and force production sense (FPS). The study group consisted of 55 healthy participants (age: 21 ± 2 years, body height: 171.2 ± 9 cm, body mass: 63.3 ± 12 kg, BMI: 21.5 ± 2.6). Local cooling was achieved with the use of gel-packs cooled to -2 ± 2.5°C and applied simultaneously over the knee joint and the quadriceps femoris muscle for 20 minutes. JPS and FPS were evaluated using the Biodex System 4 Pro apparatus. Repeated measures analysis of variance (ANOVA) did not show any statistically significant changes of the JPS and FPS under application of cryotherapy for all analyzed variables: the JPS’s absolute error (p = 0.976), its relative error (p = 0.295), and its variable error (p = 0.489); the FPS’s absolute error (p = 0.688), its relative error (p = 0.193), and its variable error (p = 0.123). The results indicate that local cooling does not affect proprioceptive acuity of the healthy knee joint. They also suggest that local limited cooling before physical activity at low velocity did not present health or injury risk in this particular study group.

Key words

  • proprioception
  • kinesthesia
  • healthy knee joint
  • cooling
Accesso libero

Modelling and Predicting Backstroke Start Performance Using Non-Linear And Linear Models

Pubblicato online: 23 Mar 2018
Pagine: 29 - 38

Astratto

Abstract

Our aim was to compare non-linear and linear mathematical model responses for backstroke start performance prediction. Ten swimmers randomly completed eight 15 m backstroke starts with feet over the wedge, four with hands on the highest horizontal and four on the vertical handgrip. Swimmers were videotaped using a dual media camera set-up, with the starts being performed over an instrumented block with four force plates. Artificial neural networks were applied to predict 5 m start time using kinematic and kinetic variables and to determine the accuracy of the mean absolute percentage error. Artificial neural networks predicted start time more robustly than the linear model with respect to changing training to the validation dataset for the vertical handgrip (3.95 ± 1.67 vs. 5.92 ± 3.27%). Artificial neural networks obtained a smaller mean absolute percentage error than the linear model in the horizontal (0.43 ± 0.19 vs. 0.98 ± 0.19%) and vertical handgrip (0.45 ± 0.19 vs. 1.38 ± 0.30%) using all input data. The best artificial neural network validation revealed a smaller mean absolute error than the linear model for the horizontal (0.007 vs. 0.04 s) and vertical handgrip (0.01 vs. 0.03 s). Artificial neural networks should be used for backstroke 5 m start time prediction due to the quite small differences among the elite level performances.

Key words

  • artificial neural networks
  • linear mathematical model
  • kinematics
  • kinetics
  • competitive swimming
  • start time
Accesso libero

Influence of Dynamic Neuromuscular Stabilization Approach on Maximum Kayak Paddling Force

Pubblicato online: 23 Mar 2018
Pagine: 15 - 27

Astratto

Abstract

The purpose of this study was to examine the effect of Dynamic Neuromuscular Stabilization (DNS) exercise on maximum paddling force (PF) and self-reported pain perception in the shoulder girdle area in flatwater kayakers. Twenty male flatwater kayakers from a local club (age = 21.9 ± 2.4 years, body height = 185.1 ± 7.9 cm, body mass = 83.9 ± 9.1 kg) were randomly assigned to the intervention or control groups. During the 6-week study, subjects from both groups performed standard off-season training. Additionally, the intervention group engaged in a DNS-based core stabilization exercise program (quadruped exercise, side sitting exercise, sitting exercise and squat exercise) after each standard training session. Using a kayak ergometer, the maximum PF stroke was measured four times during the six weeks. All subjects completed the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire before and after the 6-week interval to evaluate subjective pain perception in the shoulder girdle area. Initially, no significant differences in maximum PF and the DASH questionnaire were identified between the two groups. Repeated measures analysis of variance indicated that the experimental group improved significantly compared to the control group on maximum PF (p = .004; Cohen’s d = .85), but not on the DASH questionnaire score (p = .731) during the study. Integration of DNS with traditional flatwater kayak training may significantly increase maximum PF, but may not affect pain perception to the same extent.

Key words

  • flatwater kayaking
  • postural stabilization
  • pain
  • strength
  • ergometer
Accesso libero

Muscle Activity in Upper-Body Single-Joint Resistance Exercises with Elastic Resistance Bands vs. Free Weights

Pubblicato online: 23 Mar 2018
Pagine: 5 - 13

Astratto

Abstract

Elastic resistance bands require little space, are light and portable, but their efficacy has not yet been established for several resistance exercises. The main objective of this study was to compare the muscle activation levels induced by elastic resistance bands versus conventional resistance training equipment (dumbbells) in the upper-body resistance exercises flyes and reverse flyes. The level of muscle activation was measured with surface electromyography in 29 men and women in a cross-over design where resistance loadings with elastic resistance bands and dumbbells were matched using 10-repetition maximum loadings. Elastic resistance bands induced slightly lower muscle activity in the muscles most people aim to activate during flyes and reverse flies, namely pectoralis major and deltoideus posterior, respectively. However, elastic resistance bands increased the muscle activation level substantially in perceived ancillary muscles, that is deltoideus anterior in flyes, and deltoideus medius and trapezius descendens in reverse flyes, possibly due to elastic bands being a more unstable resistance modality. Overall, the results show that elastic resistance bands can be considered a feasible alternative to dumbbells in flyes and reverse flyes.

Key words

  • electromyography
  • resistance training
  • pectoralis muscles
  • deltoid muscle

Section II – Exercise Physiology & Sports Medicine

Accesso libero

Effect of Compression Garments on Physiological Responses After Uphill Running

Pubblicato online: 23 Mar 2018
Pagine: 119 - 129

Astratto

Abstract

Limited practical recommendations related to wearing compression garments for athletes can be drawn from the literature at the present time. We aimed to identify the effects of compression garments on physiological and perceptual measures of performance and recovery after uphill running with different pressure and distributions of applied compression. In a random, double blinded study, 10 trained male runners undertook three 8 km treadmill runs at a 6% elevation rate, with the intensity of 75% VO2max while wearing low, medium grade compression garments and high reverse grade compression. In all the trials, compression garments were worn during 4 hours post run. Creatine kinase, measurements of muscle soreness, ankle strength of plantar/dorsal flexors and mean performance time were then measured. The best mean performance time was observed in the medium grade compression garments with the time difference being: medium grade compression garments vs. high reverse grade compression garments. A positive trend in increasing peak torque of plantar flexion (60o·s-1, 120o·s-1) was found in the medium grade compression garments: a difference between 24 and 48 hours post run. The highest pain tolerance shift in the gastrocnemius muscle was the medium grade compression garments, 24 hour post run, with the shift being +11.37% for the lateral head and 6.63% for the medial head. In conclusion, a beneficial trend in the promotion of running performance and decreasing muscle soreness within 24 hour post exercise was apparent in medium grade compression garments.

Key words

  • algometry
  • dynamometry
  • endurance athletes
  • external pressure
  • performance
  • recovery
Accesso libero

Urinary Steroid Profile in Ironman Triathletes

Pubblicato online: 23 Mar 2018
Pagine: 109 - 117

Astratto

Abstract

The aim of this study was to determine variations in the urinary steroid profile of triathletes following an Ironman event. A total of 10 male participants (age = 36.0 ± 1.27 years; body height = 179.29 ± 10.77 cm; body mass = 74.50 ± 1.04 kg) completed an Ironman Championship. Urine samples were collected before, immediately after, and 24 hours following the race. Gas chromatography-mass spectrometry (GC/MS) was used to detect and quantify catabolic and anabolic hormones: Androsterone, Dehydroepiandrosteone (DHEA), Androstenedione and Testosterone (T), Betaestradiol, Estrone, Progesterone, Cortisol (C), Cortisone, Tetrahydrocortisol (THE) and Tetrahydrocortisone (THF). These were measured in their glucuroconjugated and free forms. Androsterone (3297.80 ± 756.83 vs. 2154.26 ± 1375.38), DHEA (47.80 ± 19.21 vs. 32.62 ± 15.96) and Beta-estradiol (59.36 ± 11.7 vs. 41.67 ± 10.59) levels decreased after the event. The significant decrease of DHEA (47.80 ± 19.21 vs. 32.11 ± 14.03) remained at 24 hours. Cortisol (200.38 ± 56.60 vs. 257.10 ± 74.00) and THE (238.65 ± 81.55 vs. 289.62 ± 77.13) increased after exercise and remained elevated 24 hours later (200.38 ± 56.60 vs. 252.48 ± 62.09; 238.65 ± 81.55 vs. 284.20 ± 66.66). The following anabolic/catabolic ratios fell after exercise: T/C (0.85 ± 0.54 vs. 0.54 ± 0.29), T/THE (0.66 ± 0.29 vs. 0.40 ± 0.08), T/THE+THF (0.38 ± 0.17 vs. 0.24 ± 0.06), DHEA/THE (0.22 ± 0.05 vs. 0.12 ± 0.05), DHEA/THF (0.34 ± 0.02 vs. 0.21 ± 0.01) and DHEA/THE+THF (0.12 ± 0.02 vs. 0.08 ± 0.03). The steroid profile showed that athletes were fatigued after finishing the competition and a catabolic state remained 24 hours later.

Key words

  • triathlon
  • steroids
  • urine
  • gas chromatography-mass spectrometry
Accesso libero

Aerobic Fitness of Starter and Non-Starter Soccer Players in the Champion’s League

Pubblicato online: 23 Mar 2018
Pagine: 99 - 108

Astratto

Abstract

To identify individual response patterns in selected aerobic fitness variables of regular starters (ST; N = 7) and non-starters (Non-ST; N = 10), top level professional soccer players were tested for maximal oxygen uptake (VO2max), velocity at 4 mM of lactate (V4), velocity at maximal oxygen uptake (νVO2max) and oxygen pulse (O2-pulse) in July and December following consecutive periods of fixture congestion. V4 was the only variable that increased significantly in December compared to July (15.1 ± 0.5 vs. 14.6 ± 0.5, p = 0.001). There was an almost certain beneficial large mean team change for V4 (ES = 1.2 (0.67; 1.57), 100/0/0), while beneficial mean team changes were less likely for νVO2max and O2-pulse [ES = 0.31 (-0.08; 0.70), 68/30/2 and ES = 0.24 (0.01; 0.49), 64/36/0, respectively] and unclear for VO2max (ES = 0.02 (-0.31; 0.70), 18/69/13). With the exception of V4 where 10 out of 17 players (7 ST and 3 Non-ST) showed positive changes higher than the biological variability, all other variables were characterized by a substantial proportion of changes lower than the biological variability. The present study demonstrated that aerobic fitness variables that require maximal effort may be characterized by greater variability of the individual response pattern compared to that of submaximal aerobic fitness variables irrespective of the accumulated game time. Submaximal aerobic fitness variables appear to be more informative in the physiological evaluation of top level soccer players and this may be an advantage during exposure to periods of consecutive games.

Key words

  • magnitude-based inferences
  • smallest worthwhile change
  • biological variability
  • fixture congestion
  • submaximal endurance
Accesso libero

Fatigue Responses in Various Muscle Groups in Well-Trained Competitive Male Players after a Simulated Soccer Game

Pubblicato online: 23 Mar 2018
Pagine: 85 - 97

Astratto

Abstract

We examined the degree of post-game fatigue and the recovery pattern in various leg and upper-body muscle groups after a simulated soccer game. Well-trained competitive male soccer players (n = 12) participated in the study. The players completed the Copenhagen Soccer Test, a 2 x 45 min simulated soccer protocol, following baseline measures of maximal voluntary contractions of multiple muscle groups and systemic markers of muscle damage and inflammation at 0, 24 and 48 h into recovery. All muscle groups had a strength decrement (p ≤ 0.05) at 0 h post-match with knee flexors (14 ± 3%) and hip abductors (6 ± 1%) demonstrating the largest and smallest impairment. However, 24 h into recovery all individual muscles had recovered. When pooled in specific muscle groups, the trunk muscles and knee joint muscles presented the largest decline 0 h post-match, 11 ± 2% for both, with the performance decrement still persistent (4 ± 1%, p ≤ 0.05) for trunk muscles 24 h into recovery. Large inter-player variations were observed in game-induced fatigue and recovery patterns in the various muscle groups. Markers of muscle damage and inflammation peaked 0 h post-match (myoglobin) and 24 h into recovery (creatine kinase), respectively, but thereafter returned to baseline. Intermittent test performance correlated with creatine kinase activity 24 h after the Copenhagen Soccer Test (r = -0.70; p = 0.02). In conclusion, post-game fatigue is evident in multiple muscle groups with knee flexors showing the greatest performance decrement. Fatigue and recovery patterns vary markedly between muscle groups and players, yet trunk muscles display the slowest recovery.

Key words

  • muscle fatigue
  • recovery
  • muscle damage
  • inflammation
  • soccer
Accesso libero

The Effects of Aerobic Exercise and Gaming on Cognitive Performance

Pubblicato online: 23 Mar 2018
Pagine: 73 - 83

Astratto

Abstract

The purpose of our study was to investigate the effects of video gaming, aerobic exercise (biking), and the combination of these two activities on the domains of cognitive performance: selective attention, processing speed, and executive functioning. The study was a randomized clinical trial with 40 subjects (mean age 23.7 ± 1.8 years) randomized to one of four thirty-minute conditions: video gaming, biking, simultaneous gaming and biking, and a control condition. Cognitive performance was measured pre and post condition using the Stroop test and Trails B test. A mixed design was utilized. While video gaming, biking, simultaneous gaming and biking conditions improved selective attention and processing speed (p < 0.05), only the bike condition improved the highest order of cognitive performance, executive function (p < 0.01). There were no changes in cognitive performance for the control condition. Previous studies have shown that if tasks approach the limits of attentional capacity there is an increase in the overall chance for errors, known as the dual-task deficit. Simultaneous biking and gaming may have surpassed attentional capacity limits, ultimately increasing errors during the executive function tests of our cognitive performance battery. The results suggest that the fatiguing effects of a combined physically and mentally challenging task that extends after the exercise cessation may overcome the eventual beneficial cognitive effects derived from the physical exercise.

Key words

  • executive function
  • Stroop
  • exercise
  • video gaming
Accesso libero

Can Supplementation of Vitamin D Improve Aerobic Capacity in Well Trained Youth Soccer Players?

Pubblicato online: 23 Mar 2018
Pagine: 63 - 72

Astratto

Abstract

There is no clear evidence that vitamin D effectively improves physical capacity in high-level athletes. The aim of this study was to confirm that vitamin D supplementation of soccer players during eight-week high-intensity training would have a significant effect on their aerobic capacity. The subjects were divided into two groups: the experimental one that was supplemented with vitamin D (SG, n = 20), and the placebo group (PG, n = 16), not supplemented with vitamin D. All the players were subjected to the same soccer training described as High-Intensity Interval Training (HIIT). The data of the vitamin D level, PWC170, lactate threshold (LT) were collected just before and after the intervention. A significant increase in vitamin D concentration (119%) was observed in the supplemented group, while the non-supplemented group showed a decrease of 8.4%. The studied subjects improved VO2max results by 20% in the SG, and by 13% in the PG. The improvement in velocity at the LT was similar in both groups. Results of this study show that vitamin D can have a positive, though moderate, effect on aerobic performance in players subjected to high-intensity training in the form of small-sided games for 8 weeks.

Key words

  • soccer
  • training load
  • nutrition
  • youth athletes

Section III – Sports Training

Accesso libero

Physical Performance Comparison Between Under 15 Elite and Sub-Elite Soccer Players

Pubblicato online: 23 Mar 2018
Pagine: 209 - 216

Astratto

Abstract

The aim of this study was to compare the physical performance profile among young soccer players of different competitive levels. Two teams of elite (n = 22) and sub-elite (n = 22) soccer players at national (highly skilled) and regional (moderately skilled) level were recruited in the study. All participants were tested using a modified Illinois change of direction speed test, a T-drill with and without a ball, a countermovement jump, and a 10-m sprint. The analysis revealed significant differences in favor of elite players in sprint (d = 1.54, large) and vertical jump (d = 2.03, very large) outcomes, while no differences were observed in both modified Illinois change of direction speed (d = 0.16, trivial) and T-drill (d = 0.20, small) tests between the groups. The ability to change direction and speed with and without a ball was found not to be suitable enough to highlight the difference among youth players with moderate-to-high level of play. In conclusion, multi-testing approach based on task-related power should include vertical jump and sprint performance to delineate players of a higher level.

Key words

  • talent selection
  • change of direction speed
  • skill assessment
  • team sports
  • anaerobic power
Accesso libero

Responsiveness of The Countermovement Jump and Handgrip Strength to an Incremental Running Test in Endurance Athletes: Influence of Sex

Pubblicato online: 23 Mar 2018
Pagine: 199 - 208

Astratto

Abstract

The present study analyzed the acute effects of an incremental running test on countermovement jump (CMJ) and handgrip strength performance in endurance athletes, considering the effect of post-exercise recovery time and sex. Thirty-three recreationally trained long-distance runners, 20 men and 13 women, participated voluntarily in this study. The participants performed the Léger test, moreover, the CMJ and handgrip strength tests were carried out before and after the running test and during different stages of recovery (at the 1st min of recovery (posttest1), 5th min of recovery (posttest2), and 10th min of recovery (posttest3)). Two-way analysis of variance revealed a significant improvement in the CMJ (pre-posttest1, p = 0.001) and handgrip strength (pre-posttest2, p = 0.017) during recovery time. The Pearson’s Chi-2 test showed no significant relationship (p ≥ 0.05) between sex and post-activation potentiation (PAP). A linear regression analysis pointed to heart rate recovery as a predictive factor of CMJ improvement (PAP). In conclusion, despite significant fatigue reached during the Léger test, the long-distance runners did not experience an impaired CMJ and handgrip strength performance, either men or women, achieving an improvement (PAP) in posttest conditions. The results obtained showed no significant relationship between sex and PAP. Moreover, significant effect of recovery after running at high intensity on CMJ performance and handgrip strength was found. Finally, the data suggest that PAP condition can be predicted by heart rate recovery in endurance runners.

Key words

  • long-distance runner
  • post-activation potentiation
  • fatigue
  • recovery time
  • rapid force
Accesso libero

Effects of Different Post-Activation Potentiation Warm-Ups on Repeated Sprint Ability in Soccer Players from Different Competitive Levels

Pubblicato online: 23 Mar 2018
Pagine: 189 - 197

Astratto

Abstract

This study aimed to compare the effects of a traditional warm-up with two post-activation potentiation (PAP) warm-up strategies on the repeated sprint ability (RSA) of soccer players from national (NL) and regional (RL) competitive levels. Sixteen young players (NL, n = 8, age = 20.7 ± 1.4 y, body mass = 68.5 ± 7.0 kg, body height = 177.4 ± 5.2 cm; RL, n = 8, age = 20.8 ± 1.0 y, body mass = 68.7 ± 4.0 kg, body height = 176.6 ± 5.6 cm) were recruited to complete a traditional warm-up (CONTROL), a PAP warm-up incorporating squats with a load (~60% 1RM) that allowed a high speed (1 m/s) of movement and a high number of repetitions (PAP-1), and a PAP warm-up with a load (~90% 1RM) that allowed a moderate speed (0.5 m/s) of movement and a reduced number of repetitions (PAP-0.5). A RSA test (six 20-m sprints with 20 s of recovery) was performed 5 min after the PAP warm-up to assess the effects of the different protocols on the fastest sprint (RSAb) and the mean time of all sprints (RSAm). A meaningful improvement of RSA performance was observed with PAP-0.5, attaining a large effect on NL (RSAb, ES = -1.5; RSAm, ES = -1.3) and only a small effect on RL athletes (RSAb and RSAm, ES = -0.2). Moreover, when each RSA sprint performance was compared between NL and RL players, after PAP-0.5 greater performance for all sprints was observed in the NL players. Therefore, adding a heavy strength-based conditioning exercise during the warm-up prior to a RSA test may induce significant performance improvements in NL, but only small effects in RL players.

Key words

  • soccer
  • explosive actions
  • fatigue
  • back squats
  • athletes
Accesso libero

Effect of Two Different Types of Olympic Rotation Order on Cardiovascular and Metabolic Variables in Men’s Artistic Gymnastics

Pubblicato online: 23 Mar 2018
Pagine: 179 - 187

Astratto

Abstract

The rotation sequence-order differs from a gymnast to another according to the draw at the time of the qualifying competitions in men’s artistic gymnastics. Only the six best gymnasts start on the floor exercises, the others could start on any of the other five apparatuses. It has been demonstrated that some gymnastics events are physiologically less taxing than others; hence some gymnasts could experience lower and/or higher levels of cardiovascular and metabolic stress compared to others, depending on the apparatus they start with. In this regard, the objective of this investigation was to compare cardiovascular and metabolic variables between two different types of Olympic rotation-order; one began with the floor exercises and the other began with the pommel horse. Six elite male gymnasts took part in this investigation. Heart rates, synchronized with real-time video acquisition, as well as capillary lactate concentration following each apparatus routine were monitored. Cardiovascular and metabolic stresses were significantly higher when gymnasts started their rotation with the pommel horse in all apparatuses except the pommel horse. The floor exercises’ score was significantly affected when gymnasts ended up their competition on this apparatus. As a conclusion, starting gymnastics’ competition on the floor exercises implicates less cardiovascular and metabolic stress associated with better performance compared with the other rotation order. As a matter of fact, best gymnasts who start on this apparatus could have a slight advantage compared with the other athletes.

Key words

  • gymnastics
  • heart rate
  • blood lactate
  • recovery
  • apparatus
  • score
Accesso libero

Variables that Predict Serve Efficacy in Elite Men’s Volleyball with Different Quality of Opposition Sets

Pubblicato online: 23 Mar 2018
Pagine: 167 - 177

Astratto

Abstract

The objective of this study was to determine the variables that predicted serve efficacy in elite men’s volleyball, in sets with different quality of opposition. 3292 serve actions were analysed, of which 2254 were carried out in high quality of opposition sets and 1038 actions were in low quality of opposition sets, corresponding to a total of 24 matches played during the Men’s European Volleyball Championships held in 2011. The independent variables considered in this study were the serve zone, serve type, serving player, serve direction, reception zone, receiving player and reception type; the dependent variable was serve efficacy and the situational variable was quality of opposition sets. The variables that acted as predictors in both high and low quality of opposition sets were the serving player, reception zone and reception type. The serve type variable only acted as a predictor in high quality of opposition sets, while the serve zone variable only acted as a predictor in low quality of opposition sets. These results may provide important guidance in men’s volleyball training processes.

Key words

  • match analysis
  • serve
  • volleyball
  • multinomial logistic regression
Accesso libero

Strength and Conditioning Coaches’ Application of the Session Rating of Perceived Exertion Method of Monitoring Within Professional Rugby Union

Pubblicato online: 23 Mar 2018
Pagine: 155 - 166

Astratto

Abstract

Session rating of perceived exertion (session-RPE) is a method of monitoring and managing training loads. The purpose of this study was to research how and for what purpose strength and conditioning (S&C) coaches implement this monitoring method within professional rugby union. The study also aimed to assess if S&C coaches found this monitoring method to be valid and effective. An online survey containing 24 fixed response questions was used to assess how S&C coaches applied the session-RPE method. The survey was piloted with expert researchers and practitioners in the area of session-RPE prior to distribution and alterations were made to the survey based on the experts’ feedback. Twenty S&C coaches working with professional rugby union clubs in Ireland, England, Scotland and Wales completed the survey. The coaches’ responses indicated that the majority found the session-RPE to be a valid and effective monitoring method. While some good implementation practices were identified, not all of the coaches adhered to these guidelines which may impact on the accuracy of the collected data. For example, 30% of coaches do not collect the RPE for every session that a player does per week limiting the use of the session-RPE variables cumulative training load, training monotony, training strain and acute:chronic load ratio. S&C coaches within rugby should consider using session-RPE as a method of monitoring and implement the method in a manner reflective of research findings to enhance the potential applications of this system in maximising adaptations and minimising the risk of injury.

Key words

  • monitoring
  • training monotony
  • training load
  • training strain
  • acute:chronic load ratio
Accesso libero

Variance In Prominence Levels and in Patterns of Passing Sequences in Elite and Youth Soccer Players: A Network Approach

Pubblicato online: 23 Mar 2018
Pagine: 141 - 153

Astratto

Abstract

The aim of this study was to quantify the prominence levels of elite and highly competitive young soccer players. This study also analyzed the variation in general network properties at different competitive levels and periods of the season. A total of 132 matches, played by 28 teams during the 2015/2016 season, were analyzed. The results revealed significant differences in the composition of general network measures considering the competitive level (p = 0.002; ES = 0.077) and according to the location of the match (p = 0.001; ES = 0.147). There were positive correlations between network density and the final score (ρ = 0.172) and negative correlations between network density and goals conceded (ρ = - 0.300). Significant differences in the composite of centralities were found between positions (p = 0.001; ES = 0.293; moderate effect) and the location of the match (p = 0.001; ES = 0.013; no effect). This revealed that the general properties of cooperation increased with the competitive level, improved during the middle of the season and were better in home matches. Midfielders were most prominent players in elite and U19 teams in the mid-season and central defenders had the most prominent centralities in U17 and U15 during the early and late periods of the season.

Key words

  • applied mathematics
  • graph theory
  • soccer
  • match analysis
Accesso libero

Impact of Official Matches on Soccer Referees’ Power Performance

Pubblicato online: 23 Mar 2018
Pagine: 131 - 140

Astratto

Abstract

The evaluation of match officials’ neuromuscular performance is now an important consideration and the vertical jump test is considered suitable for assessing lower limb power, partly because it is directly related to refereeing. The aim of this study, therefore, was to determine the effect of soccer matches on match officials’ vertical jump performance by assessing various biomechanical variables. Eighteen field referees (FRs) and 36 assistant referees (ARs) who officiated in 18 official matches participated in this study. Before the match, at half time and immediately after the match, officials performed two countermovement jumps. Flight phase time (FT), maximum force production (MFpropulsion), time to production of maximum force (TMFpropulsion), production of maximum power (MP), maximum landing force (MFlanding) and time to stabilization (TTS) were calculated for all jumps. There was a tendency for match officials’ jumping performance to improve after matches than beforehand (FR: effect size (ES) = 0.19 ± 0.36, possibly trivial; AR: ES = 0.07 ± 0.17, likely trivial). There were also likely small and very likely moderate differences between FRs’ MP in pre-match and half-time jumps (ES = 0.46 ± 0.47) and in their pre- and post-match jumps (ES = 0.71 ± 0.48). These results indicate that refereeing soccer matches does not reduce vertical jump performance; the subsequent neuromuscular fatigue is not sufficient to affect landing technique.

Key words

  • strength
  • biomechanics
  • competition
  • fatigue

Section IV – Behavioural Sciences in Sport

Accesso libero

Understanding Trail Runners’ Activity on Online Community Forums: An Inductive Analysis of Discussion Topics

Pubblicato online: 23 Mar 2018
Pagine: 263 - 276

Astratto

Abstract

Recreational trail runners often participate in online community forums where they can freely read posted messages, join discussions and/or introduce new discussion topics. This tool can enhance learning as runners connect with other trail runners and reflect on how they can better organize their own practice. Studying forum activity would provide greater insight into the relationship between field practice and dedicated forums. The aim of this study was therefore to detect the topics discussed online by trail runners in order to understand how they collectively look for solutions that help them adapt to issues that emerge during actual practice. The discussion topics (n = 171) on the forum hosted by the Raidlight brand were examined using inductive content analysis, which distinguished two general dimensions. The first dimension was training and had four first-order themes (i.e., “specific trail running sessions”, “complementary trail running sessions”. “training plans” and “specific questions about races”) grouped into two second-order themes (i.e., “training session contents” and “structure and schedule”). The second dimension was health and had seven first-order themes (i.e., “tendinitis”, “muscle issues”, “foot issues”, “sprains and fractures”, “pain”, “physiology” and “substances and practitioners”) grouped into two second-order themes (i.e., “pain and injury” and “prevention”). The results indicate that the issues that trail runners discuss on forums are significant and that the successions of questions and solutions are a fruitful means for building, enriching and adjusting their activity as they cope with constraints. As a practical consequence, suggestions for improving such online platforms are made.

Key words

  • trail running
  • forums
  • training
  • health
  • activity
  • communities of practice
Accesso libero

Motivational Climate Sport Youth Scale: Measurement Invariance Across Gender and Five Different Sports

Pubblicato online: 23 Mar 2018
Pagine: 249 - 261

Astratto

Abstract

The aim of this study was to analyze the psychometric properties of the Portuguese version of the Motivational Climate Sport Youth Scale (MCSYSp) and invariance across gender and different sports (swimming, soccer, handball, basketball, futsal). A total of 4,569 athletes (3,053 males, 1,516 females) from soccer (1,098), swimming (1,049), basketball (1,754), futsal (340), and handball (328) participated in this study, with ages between 10 and 20 years (M = 15.13; SD = 1.95). The results show that the original model (two factors/12 items) did not adjust to the data in a satisfactory way; therefore, it was necessary to change the model by removing four items (two from each factor). Subsequently, the model adjusted to the data in a satisfactory way (χ2 = 499.84; df = 19; χ2/df = 26.30; p < .001; SRMR = .037; TLI = .923; CFI = .948; RMSEA = .074; IC90% .069–.080) and was invariant by gender and team sports (soccer, handball, basketball, futsal) (ΔCFK≤.01); however, it was not invariant between swimming and team sports (soccer, handball, basketball, futsal) (ΔCFI ≥ .01). In conclusion, the MCSYSp (two factors/eight items) is a valid and reliable choice that is transversal not only to gender, but also to the different studied team sports to measure the perception of the motivational climate in athletes. Future studies can research more deeply the invariance analysis between individual sports to better understand the invariance of the model between individual and team sports.

Key words

  • motivation
  • achievement goal theory
  • sports
  • gender
  • multi-group analysis
Accesso libero

Competition Field Perceptions of Table-tennis Athletes and their Performance

Pubblicato online: 23 Mar 2018
Pagine: 241 - 247

Astratto

Abstract

The distinction between positive and negative perceptions is fundamental in perception models. The purpose of this study was to investigate the correlation between field perceptions of table tennis players and the outcome (net result) during the matches in a competition. Experimental data were collected from 10 elite table tennis players and analysed. The results addressed the following three competition field perceptions: (1) before the service, the player’s positive perceptions had significant effect on the positive outcome (winning rate) of that service; (2) the perception after the net result of the previous service increased the positive outcome of the next service, and (3) the player’s positive/negative perception during the matches affected the win/loss outcome of that competition. In conclusion, the player’s positive perceptions enhanced their winning rate during table tennis competitions. Therefore, during the training program, coaches need to develop positive perceptions and strengthen the psychological quality of table tennis players.

Key words

  • positive perception
  • negative perception
  • psychological quality
  • table tennis
Accesso libero

Analysis of Tactical, Decisional and Executional Behaviour According to the Level of Expertise in Squash

Pubblicato online: 23 Mar 2018
Pagine: 227 - 240

Astratto

Abstract

The objective of this study was to analyse the differences in tactical principles, decision-making and execution of the return shot and drop shot of squash players at different levels of proficiency. The sample was composed of 80 players, divided into four levels of expertise (first national category, second national category, autonomous regional level and provincial level). The Squash Performance Evaluation Tool was used for recording the level of decision-making and execution. The results revealed that reading of the context of the game improved as the level of the player’s expertise of both the return shot and the drop shot increased. The correlation between correct decision-making and better quality execution for both the return shot and the drop shot in squash also improved with the player’s level of expertise. According to these results, improvements in situational tactical principles and the application of tactical principles, correct decision-making and high-quality execution are essential to develop the athletic performance level among squash players.

Key words

  • tactical awareness
  • decision making
  • performance
  • evaluation
  • net games
  • sport
Accesso libero

Validation and Reliability of the Korean Version of the Sport Anxiety Scale-2

Pubblicato online: 23 Mar 2018
Pagine: 217 - 225

Astratto

Abstract

The main purpose of the present study was to examine the validation and reliability of the Korean version of the Sport Anxiety Scale (SAS-2Kr) by evaluating its factorial invariance across gender. A total of 303 Korean collegiate athletes (198 males and 105 females) from 9 sports participated in the study, and they completed the demographic questionnaire and the SAS-2Kr containing 15 items to measure multidimensional trait anxiety and individual differences in the cognitive and somatic anxiety experienced by athletes. The results of this study indicated that the construct validity in the SAS-2Kr was well established in that the values of the standardized factor loadings, composite reliability, and average variance extracted values were above the recommended cutoff points. The multiple-sample confirmatory factor analyses showed the SAS-2Kr could be generalizable across gender in college samples. The results also indicated that the SAS-2Kr supported the original 3-factor model of SAS-2 in English consisting of somatic anxiety, worry, and concentration disruption, and thus this study provides useful information for researchers to understand the athletes’ tendency to experience anxiety reactions in sport situations. Suggestions for future research on competitive trait anxiety are provided in the discussion section.

Key words

  • competitive anxiety
  • trait anxiety
  • validation
  • confirmatory factor analysis (CFA)
  • factorial invariance
24 Articoli

Section I – Kinesiology

Accesso libero

Functional Movements in Japanese Mini-Basketball Players

Pubblicato online: 23 Mar 2018
Pagine: 53 - 62

Astratto

Abstract

Functional movement screen (FMS) has been used to establish normative data and determine potential injury risk for young adults and athletes, but there are few data in elementary school-age children. The purpose of this study was to establish fundamental values for the FMS in elementary school-age mini-basketball players. Secondary purposes were to examine relationships between functional movement patterns and age, peak height velocity (PHV), and body mass index (BMI), and to compare functional movement patterns between boys and girls and between individuals with and without a history of injury. The mean composite FMS score was 16.5 ± 2.2 (16.5 ± 2.4 for boys, 16.5 ± 1.7 for girls). The composite FMS score was positively correlated with age (r = .312) and negatively correlated with the BMI (r = − .371). However, the FMS score was not correlated with PHV or with PHV age. The FMS score was not different between boys and girls or between individuals who reported a previous injury and those who did not. However, boys in the mini-basketball teams performed better than girls on the trunk stability push-up and rotary stability tests. Age and the body mass index were significantly associated with better and poorer functional movement, respectively.

Key words

  • functional movement screen
  • elementary school-aged children
  • injury risk
  • basketball players
  • youth
Accesso libero

The Effects of Cryotherapy on Knee Joint Position Sense and Force Production Sense in Healthy Individuals

Pubblicato online: 23 Mar 2018
Pagine: 39 - 51

Astratto

Abstract

The proprioceptive information received from mechanoreceptors is potentially responsible for controlling the joint position and force differentiation. However, it is unknown whether cryotherapy influences this complex mechanism. Previously reported results are not universally conclusive and sometimes even contradictory. The main objective of this study was to investigate the impact of local cryotherapy on knee joint position sense (JPS) and force production sense (FPS). The study group consisted of 55 healthy participants (age: 21 ± 2 years, body height: 171.2 ± 9 cm, body mass: 63.3 ± 12 kg, BMI: 21.5 ± 2.6). Local cooling was achieved with the use of gel-packs cooled to -2 ± 2.5°C and applied simultaneously over the knee joint and the quadriceps femoris muscle for 20 minutes. JPS and FPS were evaluated using the Biodex System 4 Pro apparatus. Repeated measures analysis of variance (ANOVA) did not show any statistically significant changes of the JPS and FPS under application of cryotherapy for all analyzed variables: the JPS’s absolute error (p = 0.976), its relative error (p = 0.295), and its variable error (p = 0.489); the FPS’s absolute error (p = 0.688), its relative error (p = 0.193), and its variable error (p = 0.123). The results indicate that local cooling does not affect proprioceptive acuity of the healthy knee joint. They also suggest that local limited cooling before physical activity at low velocity did not present health or injury risk in this particular study group.

Key words

  • proprioception
  • kinesthesia
  • healthy knee joint
  • cooling
Accesso libero

Modelling and Predicting Backstroke Start Performance Using Non-Linear And Linear Models

Pubblicato online: 23 Mar 2018
Pagine: 29 - 38

Astratto

Abstract

Our aim was to compare non-linear and linear mathematical model responses for backstroke start performance prediction. Ten swimmers randomly completed eight 15 m backstroke starts with feet over the wedge, four with hands on the highest horizontal and four on the vertical handgrip. Swimmers were videotaped using a dual media camera set-up, with the starts being performed over an instrumented block with four force plates. Artificial neural networks were applied to predict 5 m start time using kinematic and kinetic variables and to determine the accuracy of the mean absolute percentage error. Artificial neural networks predicted start time more robustly than the linear model with respect to changing training to the validation dataset for the vertical handgrip (3.95 ± 1.67 vs. 5.92 ± 3.27%). Artificial neural networks obtained a smaller mean absolute percentage error than the linear model in the horizontal (0.43 ± 0.19 vs. 0.98 ± 0.19%) and vertical handgrip (0.45 ± 0.19 vs. 1.38 ± 0.30%) using all input data. The best artificial neural network validation revealed a smaller mean absolute error than the linear model for the horizontal (0.007 vs. 0.04 s) and vertical handgrip (0.01 vs. 0.03 s). Artificial neural networks should be used for backstroke 5 m start time prediction due to the quite small differences among the elite level performances.

Key words

  • artificial neural networks
  • linear mathematical model
  • kinematics
  • kinetics
  • competitive swimming
  • start time
Accesso libero

Influence of Dynamic Neuromuscular Stabilization Approach on Maximum Kayak Paddling Force

Pubblicato online: 23 Mar 2018
Pagine: 15 - 27

Astratto

Abstract

The purpose of this study was to examine the effect of Dynamic Neuromuscular Stabilization (DNS) exercise on maximum paddling force (PF) and self-reported pain perception in the shoulder girdle area in flatwater kayakers. Twenty male flatwater kayakers from a local club (age = 21.9 ± 2.4 years, body height = 185.1 ± 7.9 cm, body mass = 83.9 ± 9.1 kg) were randomly assigned to the intervention or control groups. During the 6-week study, subjects from both groups performed standard off-season training. Additionally, the intervention group engaged in a DNS-based core stabilization exercise program (quadruped exercise, side sitting exercise, sitting exercise and squat exercise) after each standard training session. Using a kayak ergometer, the maximum PF stroke was measured four times during the six weeks. All subjects completed the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire before and after the 6-week interval to evaluate subjective pain perception in the shoulder girdle area. Initially, no significant differences in maximum PF and the DASH questionnaire were identified between the two groups. Repeated measures analysis of variance indicated that the experimental group improved significantly compared to the control group on maximum PF (p = .004; Cohen’s d = .85), but not on the DASH questionnaire score (p = .731) during the study. Integration of DNS with traditional flatwater kayak training may significantly increase maximum PF, but may not affect pain perception to the same extent.

Key words

  • flatwater kayaking
  • postural stabilization
  • pain
  • strength
  • ergometer
Accesso libero

Muscle Activity in Upper-Body Single-Joint Resistance Exercises with Elastic Resistance Bands vs. Free Weights

Pubblicato online: 23 Mar 2018
Pagine: 5 - 13

Astratto

Abstract

Elastic resistance bands require little space, are light and portable, but their efficacy has not yet been established for several resistance exercises. The main objective of this study was to compare the muscle activation levels induced by elastic resistance bands versus conventional resistance training equipment (dumbbells) in the upper-body resistance exercises flyes and reverse flyes. The level of muscle activation was measured with surface electromyography in 29 men and women in a cross-over design where resistance loadings with elastic resistance bands and dumbbells were matched using 10-repetition maximum loadings. Elastic resistance bands induced slightly lower muscle activity in the muscles most people aim to activate during flyes and reverse flies, namely pectoralis major and deltoideus posterior, respectively. However, elastic resistance bands increased the muscle activation level substantially in perceived ancillary muscles, that is deltoideus anterior in flyes, and deltoideus medius and trapezius descendens in reverse flyes, possibly due to elastic bands being a more unstable resistance modality. Overall, the results show that elastic resistance bands can be considered a feasible alternative to dumbbells in flyes and reverse flyes.

Key words

  • electromyography
  • resistance training
  • pectoralis muscles
  • deltoid muscle

Section II – Exercise Physiology & Sports Medicine

Accesso libero

Effect of Compression Garments on Physiological Responses After Uphill Running

Pubblicato online: 23 Mar 2018
Pagine: 119 - 129

Astratto

Abstract

Limited practical recommendations related to wearing compression garments for athletes can be drawn from the literature at the present time. We aimed to identify the effects of compression garments on physiological and perceptual measures of performance and recovery after uphill running with different pressure and distributions of applied compression. In a random, double blinded study, 10 trained male runners undertook three 8 km treadmill runs at a 6% elevation rate, with the intensity of 75% VO2max while wearing low, medium grade compression garments and high reverse grade compression. In all the trials, compression garments were worn during 4 hours post run. Creatine kinase, measurements of muscle soreness, ankle strength of plantar/dorsal flexors and mean performance time were then measured. The best mean performance time was observed in the medium grade compression garments with the time difference being: medium grade compression garments vs. high reverse grade compression garments. A positive trend in increasing peak torque of plantar flexion (60o·s-1, 120o·s-1) was found in the medium grade compression garments: a difference between 24 and 48 hours post run. The highest pain tolerance shift in the gastrocnemius muscle was the medium grade compression garments, 24 hour post run, with the shift being +11.37% for the lateral head and 6.63% for the medial head. In conclusion, a beneficial trend in the promotion of running performance and decreasing muscle soreness within 24 hour post exercise was apparent in medium grade compression garments.

Key words

  • algometry
  • dynamometry
  • endurance athletes
  • external pressure
  • performance
  • recovery
Accesso libero

Urinary Steroid Profile in Ironman Triathletes

Pubblicato online: 23 Mar 2018
Pagine: 109 - 117

Astratto

Abstract

The aim of this study was to determine variations in the urinary steroid profile of triathletes following an Ironman event. A total of 10 male participants (age = 36.0 ± 1.27 years; body height = 179.29 ± 10.77 cm; body mass = 74.50 ± 1.04 kg) completed an Ironman Championship. Urine samples were collected before, immediately after, and 24 hours following the race. Gas chromatography-mass spectrometry (GC/MS) was used to detect and quantify catabolic and anabolic hormones: Androsterone, Dehydroepiandrosteone (DHEA), Androstenedione and Testosterone (T), Betaestradiol, Estrone, Progesterone, Cortisol (C), Cortisone, Tetrahydrocortisol (THE) and Tetrahydrocortisone (THF). These were measured in their glucuroconjugated and free forms. Androsterone (3297.80 ± 756.83 vs. 2154.26 ± 1375.38), DHEA (47.80 ± 19.21 vs. 32.62 ± 15.96) and Beta-estradiol (59.36 ± 11.7 vs. 41.67 ± 10.59) levels decreased after the event. The significant decrease of DHEA (47.80 ± 19.21 vs. 32.11 ± 14.03) remained at 24 hours. Cortisol (200.38 ± 56.60 vs. 257.10 ± 74.00) and THE (238.65 ± 81.55 vs. 289.62 ± 77.13) increased after exercise and remained elevated 24 hours later (200.38 ± 56.60 vs. 252.48 ± 62.09; 238.65 ± 81.55 vs. 284.20 ± 66.66). The following anabolic/catabolic ratios fell after exercise: T/C (0.85 ± 0.54 vs. 0.54 ± 0.29), T/THE (0.66 ± 0.29 vs. 0.40 ± 0.08), T/THE+THF (0.38 ± 0.17 vs. 0.24 ± 0.06), DHEA/THE (0.22 ± 0.05 vs. 0.12 ± 0.05), DHEA/THF (0.34 ± 0.02 vs. 0.21 ± 0.01) and DHEA/THE+THF (0.12 ± 0.02 vs. 0.08 ± 0.03). The steroid profile showed that athletes were fatigued after finishing the competition and a catabolic state remained 24 hours later.

Key words

  • triathlon
  • steroids
  • urine
  • gas chromatography-mass spectrometry
Accesso libero

Aerobic Fitness of Starter and Non-Starter Soccer Players in the Champion’s League

Pubblicato online: 23 Mar 2018
Pagine: 99 - 108

Astratto

Abstract

To identify individual response patterns in selected aerobic fitness variables of regular starters (ST; N = 7) and non-starters (Non-ST; N = 10), top level professional soccer players were tested for maximal oxygen uptake (VO2max), velocity at 4 mM of lactate (V4), velocity at maximal oxygen uptake (νVO2max) and oxygen pulse (O2-pulse) in July and December following consecutive periods of fixture congestion. V4 was the only variable that increased significantly in December compared to July (15.1 ± 0.5 vs. 14.6 ± 0.5, p = 0.001). There was an almost certain beneficial large mean team change for V4 (ES = 1.2 (0.67; 1.57), 100/0/0), while beneficial mean team changes were less likely for νVO2max and O2-pulse [ES = 0.31 (-0.08; 0.70), 68/30/2 and ES = 0.24 (0.01; 0.49), 64/36/0, respectively] and unclear for VO2max (ES = 0.02 (-0.31; 0.70), 18/69/13). With the exception of V4 where 10 out of 17 players (7 ST and 3 Non-ST) showed positive changes higher than the biological variability, all other variables were characterized by a substantial proportion of changes lower than the biological variability. The present study demonstrated that aerobic fitness variables that require maximal effort may be characterized by greater variability of the individual response pattern compared to that of submaximal aerobic fitness variables irrespective of the accumulated game time. Submaximal aerobic fitness variables appear to be more informative in the physiological evaluation of top level soccer players and this may be an advantage during exposure to periods of consecutive games.

Key words

  • magnitude-based inferences
  • smallest worthwhile change
  • biological variability
  • fixture congestion
  • submaximal endurance
Accesso libero

Fatigue Responses in Various Muscle Groups in Well-Trained Competitive Male Players after a Simulated Soccer Game

Pubblicato online: 23 Mar 2018
Pagine: 85 - 97

Astratto

Abstract

We examined the degree of post-game fatigue and the recovery pattern in various leg and upper-body muscle groups after a simulated soccer game. Well-trained competitive male soccer players (n = 12) participated in the study. The players completed the Copenhagen Soccer Test, a 2 x 45 min simulated soccer protocol, following baseline measures of maximal voluntary contractions of multiple muscle groups and systemic markers of muscle damage and inflammation at 0, 24 and 48 h into recovery. All muscle groups had a strength decrement (p ≤ 0.05) at 0 h post-match with knee flexors (14 ± 3%) and hip abductors (6 ± 1%) demonstrating the largest and smallest impairment. However, 24 h into recovery all individual muscles had recovered. When pooled in specific muscle groups, the trunk muscles and knee joint muscles presented the largest decline 0 h post-match, 11 ± 2% for both, with the performance decrement still persistent (4 ± 1%, p ≤ 0.05) for trunk muscles 24 h into recovery. Large inter-player variations were observed in game-induced fatigue and recovery patterns in the various muscle groups. Markers of muscle damage and inflammation peaked 0 h post-match (myoglobin) and 24 h into recovery (creatine kinase), respectively, but thereafter returned to baseline. Intermittent test performance correlated with creatine kinase activity 24 h after the Copenhagen Soccer Test (r = -0.70; p = 0.02). In conclusion, post-game fatigue is evident in multiple muscle groups with knee flexors showing the greatest performance decrement. Fatigue and recovery patterns vary markedly between muscle groups and players, yet trunk muscles display the slowest recovery.

Key words

  • muscle fatigue
  • recovery
  • muscle damage
  • inflammation
  • soccer
Accesso libero

The Effects of Aerobic Exercise and Gaming on Cognitive Performance

Pubblicato online: 23 Mar 2018
Pagine: 73 - 83

Astratto

Abstract

The purpose of our study was to investigate the effects of video gaming, aerobic exercise (biking), and the combination of these two activities on the domains of cognitive performance: selective attention, processing speed, and executive functioning. The study was a randomized clinical trial with 40 subjects (mean age 23.7 ± 1.8 years) randomized to one of four thirty-minute conditions: video gaming, biking, simultaneous gaming and biking, and a control condition. Cognitive performance was measured pre and post condition using the Stroop test and Trails B test. A mixed design was utilized. While video gaming, biking, simultaneous gaming and biking conditions improved selective attention and processing speed (p < 0.05), only the bike condition improved the highest order of cognitive performance, executive function (p < 0.01). There were no changes in cognitive performance for the control condition. Previous studies have shown that if tasks approach the limits of attentional capacity there is an increase in the overall chance for errors, known as the dual-task deficit. Simultaneous biking and gaming may have surpassed attentional capacity limits, ultimately increasing errors during the executive function tests of our cognitive performance battery. The results suggest that the fatiguing effects of a combined physically and mentally challenging task that extends after the exercise cessation may overcome the eventual beneficial cognitive effects derived from the physical exercise.

Key words

  • executive function
  • Stroop
  • exercise
  • video gaming
Accesso libero

Can Supplementation of Vitamin D Improve Aerobic Capacity in Well Trained Youth Soccer Players?

Pubblicato online: 23 Mar 2018
Pagine: 63 - 72

Astratto

Abstract

There is no clear evidence that vitamin D effectively improves physical capacity in high-level athletes. The aim of this study was to confirm that vitamin D supplementation of soccer players during eight-week high-intensity training would have a significant effect on their aerobic capacity. The subjects were divided into two groups: the experimental one that was supplemented with vitamin D (SG, n = 20), and the placebo group (PG, n = 16), not supplemented with vitamin D. All the players were subjected to the same soccer training described as High-Intensity Interval Training (HIIT). The data of the vitamin D level, PWC170, lactate threshold (LT) were collected just before and after the intervention. A significant increase in vitamin D concentration (119%) was observed in the supplemented group, while the non-supplemented group showed a decrease of 8.4%. The studied subjects improved VO2max results by 20% in the SG, and by 13% in the PG. The improvement in velocity at the LT was similar in both groups. Results of this study show that vitamin D can have a positive, though moderate, effect on aerobic performance in players subjected to high-intensity training in the form of small-sided games for 8 weeks.

Key words

  • soccer
  • training load
  • nutrition
  • youth athletes

Section III – Sports Training

Accesso libero

Physical Performance Comparison Between Under 15 Elite and Sub-Elite Soccer Players

Pubblicato online: 23 Mar 2018
Pagine: 209 - 216

Astratto

Abstract

The aim of this study was to compare the physical performance profile among young soccer players of different competitive levels. Two teams of elite (n = 22) and sub-elite (n = 22) soccer players at national (highly skilled) and regional (moderately skilled) level were recruited in the study. All participants were tested using a modified Illinois change of direction speed test, a T-drill with and without a ball, a countermovement jump, and a 10-m sprint. The analysis revealed significant differences in favor of elite players in sprint (d = 1.54, large) and vertical jump (d = 2.03, very large) outcomes, while no differences were observed in both modified Illinois change of direction speed (d = 0.16, trivial) and T-drill (d = 0.20, small) tests between the groups. The ability to change direction and speed with and without a ball was found not to be suitable enough to highlight the difference among youth players with moderate-to-high level of play. In conclusion, multi-testing approach based on task-related power should include vertical jump and sprint performance to delineate players of a higher level.

Key words

  • talent selection
  • change of direction speed
  • skill assessment
  • team sports
  • anaerobic power
Accesso libero

Responsiveness of The Countermovement Jump and Handgrip Strength to an Incremental Running Test in Endurance Athletes: Influence of Sex

Pubblicato online: 23 Mar 2018
Pagine: 199 - 208

Astratto

Abstract

The present study analyzed the acute effects of an incremental running test on countermovement jump (CMJ) and handgrip strength performance in endurance athletes, considering the effect of post-exercise recovery time and sex. Thirty-three recreationally trained long-distance runners, 20 men and 13 women, participated voluntarily in this study. The participants performed the Léger test, moreover, the CMJ and handgrip strength tests were carried out before and after the running test and during different stages of recovery (at the 1st min of recovery (posttest1), 5th min of recovery (posttest2), and 10th min of recovery (posttest3)). Two-way analysis of variance revealed a significant improvement in the CMJ (pre-posttest1, p = 0.001) and handgrip strength (pre-posttest2, p = 0.017) during recovery time. The Pearson’s Chi-2 test showed no significant relationship (p ≥ 0.05) between sex and post-activation potentiation (PAP). A linear regression analysis pointed to heart rate recovery as a predictive factor of CMJ improvement (PAP). In conclusion, despite significant fatigue reached during the Léger test, the long-distance runners did not experience an impaired CMJ and handgrip strength performance, either men or women, achieving an improvement (PAP) in posttest conditions. The results obtained showed no significant relationship between sex and PAP. Moreover, significant effect of recovery after running at high intensity on CMJ performance and handgrip strength was found. Finally, the data suggest that PAP condition can be predicted by heart rate recovery in endurance runners.

Key words

  • long-distance runner
  • post-activation potentiation
  • fatigue
  • recovery time
  • rapid force
Accesso libero

Effects of Different Post-Activation Potentiation Warm-Ups on Repeated Sprint Ability in Soccer Players from Different Competitive Levels

Pubblicato online: 23 Mar 2018
Pagine: 189 - 197

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Abstract

This study aimed to compare the effects of a traditional warm-up with two post-activation potentiation (PAP) warm-up strategies on the repeated sprint ability (RSA) of soccer players from national (NL) and regional (RL) competitive levels. Sixteen young players (NL, n = 8, age = 20.7 ± 1.4 y, body mass = 68.5 ± 7.0 kg, body height = 177.4 ± 5.2 cm; RL, n = 8, age = 20.8 ± 1.0 y, body mass = 68.7 ± 4.0 kg, body height = 176.6 ± 5.6 cm) were recruited to complete a traditional warm-up (CONTROL), a PAP warm-up incorporating squats with a load (~60% 1RM) that allowed a high speed (1 m/s) of movement and a high number of repetitions (PAP-1), and a PAP warm-up with a load (~90% 1RM) that allowed a moderate speed (0.5 m/s) of movement and a reduced number of repetitions (PAP-0.5). A RSA test (six 20-m sprints with 20 s of recovery) was performed 5 min after the PAP warm-up to assess the effects of the different protocols on the fastest sprint (RSAb) and the mean time of all sprints (RSAm). A meaningful improvement of RSA performance was observed with PAP-0.5, attaining a large effect on NL (RSAb, ES = -1.5; RSAm, ES = -1.3) and only a small effect on RL athletes (RSAb and RSAm, ES = -0.2). Moreover, when each RSA sprint performance was compared between NL and RL players, after PAP-0.5 greater performance for all sprints was observed in the NL players. Therefore, adding a heavy strength-based conditioning exercise during the warm-up prior to a RSA test may induce significant performance improvements in NL, but only small effects in RL players.

Key words

  • soccer
  • explosive actions
  • fatigue
  • back squats
  • athletes
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Effect of Two Different Types of Olympic Rotation Order on Cardiovascular and Metabolic Variables in Men’s Artistic Gymnastics

Pubblicato online: 23 Mar 2018
Pagine: 179 - 187

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Abstract

The rotation sequence-order differs from a gymnast to another according to the draw at the time of the qualifying competitions in men’s artistic gymnastics. Only the six best gymnasts start on the floor exercises, the others could start on any of the other five apparatuses. It has been demonstrated that some gymnastics events are physiologically less taxing than others; hence some gymnasts could experience lower and/or higher levels of cardiovascular and metabolic stress compared to others, depending on the apparatus they start with. In this regard, the objective of this investigation was to compare cardiovascular and metabolic variables between two different types of Olympic rotation-order; one began with the floor exercises and the other began with the pommel horse. Six elite male gymnasts took part in this investigation. Heart rates, synchronized with real-time video acquisition, as well as capillary lactate concentration following each apparatus routine were monitored. Cardiovascular and metabolic stresses were significantly higher when gymnasts started their rotation with the pommel horse in all apparatuses except the pommel horse. The floor exercises’ score was significantly affected when gymnasts ended up their competition on this apparatus. As a conclusion, starting gymnastics’ competition on the floor exercises implicates less cardiovascular and metabolic stress associated with better performance compared with the other rotation order. As a matter of fact, best gymnasts who start on this apparatus could have a slight advantage compared with the other athletes.

Key words

  • gymnastics
  • heart rate
  • blood lactate
  • recovery
  • apparatus
  • score
Accesso libero

Variables that Predict Serve Efficacy in Elite Men’s Volleyball with Different Quality of Opposition Sets

Pubblicato online: 23 Mar 2018
Pagine: 167 - 177

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Abstract

The objective of this study was to determine the variables that predicted serve efficacy in elite men’s volleyball, in sets with different quality of opposition. 3292 serve actions were analysed, of which 2254 were carried out in high quality of opposition sets and 1038 actions were in low quality of opposition sets, corresponding to a total of 24 matches played during the Men’s European Volleyball Championships held in 2011. The independent variables considered in this study were the serve zone, serve type, serving player, serve direction, reception zone, receiving player and reception type; the dependent variable was serve efficacy and the situational variable was quality of opposition sets. The variables that acted as predictors in both high and low quality of opposition sets were the serving player, reception zone and reception type. The serve type variable only acted as a predictor in high quality of opposition sets, while the serve zone variable only acted as a predictor in low quality of opposition sets. These results may provide important guidance in men’s volleyball training processes.

Key words

  • match analysis
  • serve
  • volleyball
  • multinomial logistic regression
Accesso libero

Strength and Conditioning Coaches’ Application of the Session Rating of Perceived Exertion Method of Monitoring Within Professional Rugby Union

Pubblicato online: 23 Mar 2018
Pagine: 155 - 166

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Abstract

Session rating of perceived exertion (session-RPE) is a method of monitoring and managing training loads. The purpose of this study was to research how and for what purpose strength and conditioning (S&C) coaches implement this monitoring method within professional rugby union. The study also aimed to assess if S&C coaches found this monitoring method to be valid and effective. An online survey containing 24 fixed response questions was used to assess how S&C coaches applied the session-RPE method. The survey was piloted with expert researchers and practitioners in the area of session-RPE prior to distribution and alterations were made to the survey based on the experts’ feedback. Twenty S&C coaches working with professional rugby union clubs in Ireland, England, Scotland and Wales completed the survey. The coaches’ responses indicated that the majority found the session-RPE to be a valid and effective monitoring method. While some good implementation practices were identified, not all of the coaches adhered to these guidelines which may impact on the accuracy of the collected data. For example, 30% of coaches do not collect the RPE for every session that a player does per week limiting the use of the session-RPE variables cumulative training load, training monotony, training strain and acute:chronic load ratio. S&C coaches within rugby should consider using session-RPE as a method of monitoring and implement the method in a manner reflective of research findings to enhance the potential applications of this system in maximising adaptations and minimising the risk of injury.

Key words

  • monitoring
  • training monotony
  • training load
  • training strain
  • acute:chronic load ratio
Accesso libero

Variance In Prominence Levels and in Patterns of Passing Sequences in Elite and Youth Soccer Players: A Network Approach

Pubblicato online: 23 Mar 2018
Pagine: 141 - 153

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Abstract

The aim of this study was to quantify the prominence levels of elite and highly competitive young soccer players. This study also analyzed the variation in general network properties at different competitive levels and periods of the season. A total of 132 matches, played by 28 teams during the 2015/2016 season, were analyzed. The results revealed significant differences in the composition of general network measures considering the competitive level (p = 0.002; ES = 0.077) and according to the location of the match (p = 0.001; ES = 0.147). There were positive correlations between network density and the final score (ρ = 0.172) and negative correlations between network density and goals conceded (ρ = - 0.300). Significant differences in the composite of centralities were found between positions (p = 0.001; ES = 0.293; moderate effect) and the location of the match (p = 0.001; ES = 0.013; no effect). This revealed that the general properties of cooperation increased with the competitive level, improved during the middle of the season and were better in home matches. Midfielders were most prominent players in elite and U19 teams in the mid-season and central defenders had the most prominent centralities in U17 and U15 during the early and late periods of the season.

Key words

  • applied mathematics
  • graph theory
  • soccer
  • match analysis
Accesso libero

Impact of Official Matches on Soccer Referees’ Power Performance

Pubblicato online: 23 Mar 2018
Pagine: 131 - 140

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Abstract

The evaluation of match officials’ neuromuscular performance is now an important consideration and the vertical jump test is considered suitable for assessing lower limb power, partly because it is directly related to refereeing. The aim of this study, therefore, was to determine the effect of soccer matches on match officials’ vertical jump performance by assessing various biomechanical variables. Eighteen field referees (FRs) and 36 assistant referees (ARs) who officiated in 18 official matches participated in this study. Before the match, at half time and immediately after the match, officials performed two countermovement jumps. Flight phase time (FT), maximum force production (MFpropulsion), time to production of maximum force (TMFpropulsion), production of maximum power (MP), maximum landing force (MFlanding) and time to stabilization (TTS) were calculated for all jumps. There was a tendency for match officials’ jumping performance to improve after matches than beforehand (FR: effect size (ES) = 0.19 ± 0.36, possibly trivial; AR: ES = 0.07 ± 0.17, likely trivial). There were also likely small and very likely moderate differences between FRs’ MP in pre-match and half-time jumps (ES = 0.46 ± 0.47) and in their pre- and post-match jumps (ES = 0.71 ± 0.48). These results indicate that refereeing soccer matches does not reduce vertical jump performance; the subsequent neuromuscular fatigue is not sufficient to affect landing technique.

Key words

  • strength
  • biomechanics
  • competition
  • fatigue

Section IV – Behavioural Sciences in Sport

Accesso libero

Understanding Trail Runners’ Activity on Online Community Forums: An Inductive Analysis of Discussion Topics

Pubblicato online: 23 Mar 2018
Pagine: 263 - 276

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Abstract

Recreational trail runners often participate in online community forums where they can freely read posted messages, join discussions and/or introduce new discussion topics. This tool can enhance learning as runners connect with other trail runners and reflect on how they can better organize their own practice. Studying forum activity would provide greater insight into the relationship between field practice and dedicated forums. The aim of this study was therefore to detect the topics discussed online by trail runners in order to understand how they collectively look for solutions that help them adapt to issues that emerge during actual practice. The discussion topics (n = 171) on the forum hosted by the Raidlight brand were examined using inductive content analysis, which distinguished two general dimensions. The first dimension was training and had four first-order themes (i.e., “specific trail running sessions”, “complementary trail running sessions”. “training plans” and “specific questions about races”) grouped into two second-order themes (i.e., “training session contents” and “structure and schedule”). The second dimension was health and had seven first-order themes (i.e., “tendinitis”, “muscle issues”, “foot issues”, “sprains and fractures”, “pain”, “physiology” and “substances and practitioners”) grouped into two second-order themes (i.e., “pain and injury” and “prevention”). The results indicate that the issues that trail runners discuss on forums are significant and that the successions of questions and solutions are a fruitful means for building, enriching and adjusting their activity as they cope with constraints. As a practical consequence, suggestions for improving such online platforms are made.

Key words

  • trail running
  • forums
  • training
  • health
  • activity
  • communities of practice
Accesso libero

Motivational Climate Sport Youth Scale: Measurement Invariance Across Gender and Five Different Sports

Pubblicato online: 23 Mar 2018
Pagine: 249 - 261

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Abstract

The aim of this study was to analyze the psychometric properties of the Portuguese version of the Motivational Climate Sport Youth Scale (MCSYSp) and invariance across gender and different sports (swimming, soccer, handball, basketball, futsal). A total of 4,569 athletes (3,053 males, 1,516 females) from soccer (1,098), swimming (1,049), basketball (1,754), futsal (340), and handball (328) participated in this study, with ages between 10 and 20 years (M = 15.13; SD = 1.95). The results show that the original model (two factors/12 items) did not adjust to the data in a satisfactory way; therefore, it was necessary to change the model by removing four items (two from each factor). Subsequently, the model adjusted to the data in a satisfactory way (χ2 = 499.84; df = 19; χ2/df = 26.30; p < .001; SRMR = .037; TLI = .923; CFI = .948; RMSEA = .074; IC90% .069–.080) and was invariant by gender and team sports (soccer, handball, basketball, futsal) (ΔCFK≤.01); however, it was not invariant between swimming and team sports (soccer, handball, basketball, futsal) (ΔCFI ≥ .01). In conclusion, the MCSYSp (two factors/eight items) is a valid and reliable choice that is transversal not only to gender, but also to the different studied team sports to measure the perception of the motivational climate in athletes. Future studies can research more deeply the invariance analysis between individual sports to better understand the invariance of the model between individual and team sports.

Key words

  • motivation
  • achievement goal theory
  • sports
  • gender
  • multi-group analysis
Accesso libero

Competition Field Perceptions of Table-tennis Athletes and their Performance

Pubblicato online: 23 Mar 2018
Pagine: 241 - 247

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Abstract

The distinction between positive and negative perceptions is fundamental in perception models. The purpose of this study was to investigate the correlation between field perceptions of table tennis players and the outcome (net result) during the matches in a competition. Experimental data were collected from 10 elite table tennis players and analysed. The results addressed the following three competition field perceptions: (1) before the service, the player’s positive perceptions had significant effect on the positive outcome (winning rate) of that service; (2) the perception after the net result of the previous service increased the positive outcome of the next service, and (3) the player’s positive/negative perception during the matches affected the win/loss outcome of that competition. In conclusion, the player’s positive perceptions enhanced their winning rate during table tennis competitions. Therefore, during the training program, coaches need to develop positive perceptions and strengthen the psychological quality of table tennis players.

Key words

  • positive perception
  • negative perception
  • psychological quality
  • table tennis
Accesso libero

Analysis of Tactical, Decisional and Executional Behaviour According to the Level of Expertise in Squash

Pubblicato online: 23 Mar 2018
Pagine: 227 - 240

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Abstract

The objective of this study was to analyse the differences in tactical principles, decision-making and execution of the return shot and drop shot of squash players at different levels of proficiency. The sample was composed of 80 players, divided into four levels of expertise (first national category, second national category, autonomous regional level and provincial level). The Squash Performance Evaluation Tool was used for recording the level of decision-making and execution. The results revealed that reading of the context of the game improved as the level of the player’s expertise of both the return shot and the drop shot increased. The correlation between correct decision-making and better quality execution for both the return shot and the drop shot in squash also improved with the player’s level of expertise. According to these results, improvements in situational tactical principles and the application of tactical principles, correct decision-making and high-quality execution are essential to develop the athletic performance level among squash players.

Key words

  • tactical awareness
  • decision making
  • performance
  • evaluation
  • net games
  • sport
Accesso libero

Validation and Reliability of the Korean Version of the Sport Anxiety Scale-2

Pubblicato online: 23 Mar 2018
Pagine: 217 - 225

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Abstract

The main purpose of the present study was to examine the validation and reliability of the Korean version of the Sport Anxiety Scale (SAS-2Kr) by evaluating its factorial invariance across gender. A total of 303 Korean collegiate athletes (198 males and 105 females) from 9 sports participated in the study, and they completed the demographic questionnaire and the SAS-2Kr containing 15 items to measure multidimensional trait anxiety and individual differences in the cognitive and somatic anxiety experienced by athletes. The results of this study indicated that the construct validity in the SAS-2Kr was well established in that the values of the standardized factor loadings, composite reliability, and average variance extracted values were above the recommended cutoff points. The multiple-sample confirmatory factor analyses showed the SAS-2Kr could be generalizable across gender in college samples. The results also indicated that the SAS-2Kr supported the original 3-factor model of SAS-2 in English consisting of somatic anxiety, worry, and concentration disruption, and thus this study provides useful information for researchers to understand the athletes’ tendency to experience anxiety reactions in sport situations. Suggestions for future research on competitive trait anxiety are provided in the discussion section.

Key words

  • competitive anxiety
  • trait anxiety
  • validation
  • confirmatory factor analysis (CFA)
  • factorial invariance

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