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Journal Details
Format
Journal
eISSN
1899-7562
First Published
13 Jan 2009
Publication timeframe
5 times per year
Languages
English

Search

Volume 51 (2016): Issue 1 (June 2016)

Journal Details
Format
Journal
eISSN
1899-7562
First Published
13 Jan 2009
Publication timeframe
5 times per year
Languages
English

Search

26 Articles

Research Article

Open Access

An investigation into the relationship between pre-competition mood states, age, gender and a national ranking in artistic gymnastics

Published Online: 02 Jul 2016
Page range: 243 - 252

Abstract

Abstract

This study investigated the relationship between pre-competition mood state factors in gymnastics by gender, age and a national ranking. Participant-gymnasts (total n=116, male n=49, female n=67) completed a Brunel Mood Scale (BRUMS) one day prior to their main competition of the year. Information was also gathered from gymnasts of gender, age and a national ranking. Consistent with theoretical predictions, results confirmed that a number of pre-competition mood states differed by age with both juniors and seniors having a higher level of anger than children (p<.05 respectively). Also, seniors demonstrated higher tension than children (p<.001). However, only anger showed significant differences by gender with male gymnasts demonstrating higher levels of anger than female gymnasts (p<.05), and with international gymnasts registering higher levels of anger compared with second class gymnasts (p<.05). Authors suggest that future research should investigate relationships between the pre-competition mood in other gymnastics-related disciplines and sports, as well as competitive performances.

Key words

  • pre-competition mood states
  • national ranking
  • artistic gymnastics
Open Access

Determinants of feedback retention in soccer players

Published Online: 02 Jul 2016
Page range: 235 - 241

Abstract

Abstract

This study analyzed soccer players’ retention of coaches’ feedback during training sessions. We intended to determine if the retention of information was influenced by the athletes’ personal characteristic (age, gender and the sports level), the quantity of information included in coach’s feedback (the number of ideas and redundancy), athletes’ perception of the relevance of the feedback information and athletes’ motivation as well as the attention level. The study that was conducted over the course of 18 sessions of soccer practice, involved 12 coaches (8 males, 4 females) and 342 athletes (246 males, 96 females), aged between 10 and 18 years old. All coach and athlete interventions were transposed to a written protocol and submitted to content analysis. Descriptive statistics and multiple linear regression were calculated. The results showed that a substantial part of the information was not retained by the athletes; in 65.5% of cases, athletes experienced difficulty in completely reproducing the ideas of the coaches and, on average, the value of feedback retention was 57.0%. Six variables with a statistically significant value were found: gender, the athletes’ sports level, redundancy, the number of transmitted ideas, athletes’ perception of the relevance of the feedback information and the athletes’ motivation level.

Key words

  • Soccer players
  • coach feedback
  • information retention
  • motivation and attention level
Open Access

Conforming and nonconforming personality and stress coping styles in combat athletes

Published Online: 02 Jul 2016
Page range: 225 - 233

Abstract

Abstract

The main objective of this study was to investigate whether the personality dimension of conformism/nonconformism was a predictor of stress coping styles in athletes training combat sports, and to present the characteristics of this personality dimension in the context of the competitors’ adaptive/innovative sport performance. Scores of 346 males practising combat sports such as kick boxing, MMA, thai boxing, boxing and wrestling were analyzed. The participants completed the Creative Behaviour Questionnaire (KANH III) measuring the conformity/nonconformity personality dimension and the Coping Inventory for Stressful Situations (CISS) measuring stress coping styles. The comparative analyses were conducted only for the groups of conformists and nonconformists. Differences in stress coping styles between conformists and nonconformists training combat sports were found as nonconformists tended to prefer the task-oriented coping style. Conclusively, a higher rate of nonconformity was associated with increasingly frequent occurrence of task-oriented coping and decreasingly frequent emotion-oriented coping.

Key words

  • combat sports
  • conformism
  • coping styles
  • nonconformism
  • personality
  • stress
Open Access

The goalkeeper influence on ball possession effectiveness in futsal

Published Online: 02 Jul 2016
Page range: 217 - 224

Abstract

Abstract

The aim of this study was to identify which variables were the best predictors of success in futsal ball possession when controlling for space and task related indicators, situational variables and the participation of the goalkeeper as a regular field player or not (5 vs. 4 or 4 vs. 4). The sample consisted of 326 situations of ball possession corresponding to 31 matches played by a team from the Spanish Futsal League during the 2010–2011, 2011–2012 and 2012–2013 seasons. Multidimensional qualitative data obtained from 10 ordered categorical variables were used. Data were analysed using chi-square analysis and multiple logistic regression analysis. Overall, the highest ball possession effectiveness was achieved when the goalkeeper participated as a regular field player (p<0.01), the duration of the ball possession was less than 10 s (p<0.01), the ball possession ended in the penalty area (p<0.01) and the defensive pressure was low (p<0.01). The information obtained on the relative effectiveness of offensive playing tactics can be used to improve team’s goal-scoring and goal preventing abilities.

Key words

  • performance analysis
  • offensive performance
  • logistic regression
  • goalkeeper
Open Access

Effects of ethnicity on the relationship between vertical jump and maximal power on a cycle ergometer

Published Online: 02 Jul 2016
Page range: 209 - 216

Abstract

Abstract

The aim of this study was to verify the impact of ethnicity on the maximal power-vertical jump relationship. Thirty-one healthy males, sixteen Caucasian (age: 26.3 ± 3.5 years; body height: 179.1 ± 5.5 cm; body mass: 78.1 ± 9.8 kg) and fifteen Afro-Caribbean (age: 24.4 ±2.6 years; body height: 178.9 ± 5.5 cm; body mass: 77.1 ± 10.3 kg) completed three sessions during which vertical jump height and maximal power of lower limbs were measured. The results showed that the values of vertical jump height and maximal power were higher for Afro-Caribbean participants (62.92 ± 6.7 cm and 14.70 ± 1.75 W∙kg-1) than for Caucasian ones (52.92 ± 4.4 cm and 12.75 ± 1.36 W∙kg-1). Moreover, very high reliability indices were obtained on vertical jump (e.g. 0.95 < ICC < 0.98) and maximal power performance (e.g. 0.75 < ICC < 0.97). However, multiple linear regression analysis showed that, for a given value of maximal power, the Afro-Caribbean participants jumped 8 cm higher than the Caucasians. Together, these results confirmed that ethnicity impacted the maximal power-vertical jump relationship over three sessions. In the current context of cultural diversity, the use of vertical jump performance as a predictor of muscular power should be considered with caution when dealing with populations of different ethnic origins.

Key words

  • power output
  • cycling
  • practice effect
  • reliability
  • ethnicity
Open Access

Physical fitness and performance of polish ice-hockey players competing at different sports levels

Published Online: 02 Jul 2016
Page range: 201 - 208

Abstract

Abstract

The study aimed to determine the values of selected aerobic and anaerobic capacity variables, physical profiles, and to analyze the results of on-ice tests performed by ice-hockey players relegated to a lower league. Performance of 24 ice-hockey players competing in the top league in the 2012/2013 season was analysed to this end. In the 2013/2014 season, 14 of them still played in the top league (the control group), while 10 played in the first league (the experimental group). The study was conducted one week after the end of the playoffs in the seasons under consideration. The results revealed that only in the experimental group the analysed variables changed significantly between the seasons. In the Wingate test, significant changes were only noted in mean relative power (a decrease from 9.91 to 9.14 W/kg; p=0.045) and relative total work (a decrease from 299.17 to 277.22 J/kg; p=0.048). The ramp test indicated significantly lower power output in its final stages (364 compared with 384 W; p=0.034), as well as a significant decrease in relative VO2max (from 52.70 to 48.30 ml/min/kg). Blood lactate concentrations were recorded at the 3rd, 6th, 9th and 12th min of recovery after the ramp test. The rate of post-exercise recovery, ∆LA, recorded after the ramp test turned out to be significantly lower. The times recorded in the on-ice “6x30 m stop” test increased from 32.18 to 33.10 s (p=0.047). The study showed that playing in a lower league where games were less intensive, training sessions shorter and less frequent, had an adverse effect on the performance level of the investigated players. Lower VO2max recorded in the study participants slowed down their rates of post-exercise recovery and led to a significantly worse performance in the 6x30 m stop test, as well as lower relative power and relative total work in the Wingate test.

Key words

  • team sports
  • recovery
  • on-ice tests
  • aerobic capacity
  • anaerobic capacity
Open Access

10 km running performance predicted by a multiple linear regression model with allometrically adjusted variables

Published Online: 02 Jul 2016
Page range: 193 - 200

Abstract

Abstract

The aim of this study was to verify the power of VO2max, peak treadmill running velocity (PTV), and running economy (RE), unadjusted or allometrically adjusted, in predicting 10 km running performance. Eighteen male endurance runners performed: 1) an incremental test to exhaustion to determine VO2max and PTV; 2) a constant submaximal run at 12 km·h−1 on an outdoor track for RE determination; and 3) a 10 km running race. Unadjusted (VO2max, PTV and RE) and adjusted variables (VO2max0.72, PTV0.72 and RE0.60) were investigated through independent multiple regression models to predict 10 km running race time. There were no significant correlations between 10 km running time and either the adjusted or unadjusted VO2max. Significant correlations (p < 0.01) were found between 10 km running time and adjusted and unadjusted RE and PTV, providing models with effect size > 0.84 and power > 0.88. The allometrically adjusted predictive model was composed of PTV0.72 and RE0.60 and explained 83% of the variance in 10 km running time with a standard error of the estimate (SEE) of 1.5 min. The unadjusted model composed of a single PVT accounted for 72% of the variance in 10 km running time (SEE of 1.9 min). Both regression models provided powerful estimates of 10 km running time; however, the unadjusted PTV may provide an uncomplicated estimation.

Key words

  • VO
  • peak of treadmill velocity
  • running economy
  • allometry
Open Access

Comparison between two types of anaerobic speed endurance training in competitive soccer players

Published Online: 02 Jul 2016
Page range: 183 - 192

Abstract

Abstract

The purpose of the present study was to examine the effects of additional in-season speed endurance production versus speed endurance maintenance training regimes on performance in competitive male soccer players. In a randomised controlled trial 18 male sub-elite players were exposed to additional speed endurance production (SEP) or speed endurance maintenance (SEM) training (two additional sessions/wk for 4 weeks) during the competitive season. Players performed the Yo-Yo intermittent recovery level 2 test (YYIR2) and a repeated sprint test (RST) pre- and post-intervention. Yo-Yo IR2 performance increased (p<0.001) by 50 ± 8% and 26 ± 5% in SEP and SEM, respectively, with greater (p=0.03) improvement in SEP. RST performance improved by 2.1 ± 0.3% and 1.3 ± 0.4% in SEP and SEM, respectively, while the RST fatigue index decreased (4.4 ± 0.8 to 3.4 ± 0.5%; p<0.04) in SEP only. Peak and average speed during training were higher (p<0.001) in SEP than in SEM (24.5 ± 0.3 vs 19.2 ± 0.3 and 15.5 ± 0.1 km·h-1 vs 9.4 ± 0.1 km·h-1). Additional in-season anaerobic speed endurance production and maintenance training improves high-intensity exercise performance in competitive soccer players with superior effects of speed endurance production training.

Key words

  • adaptation effects
  • exercise testing
  • GPS
  • football
Open Access

Effect of the pitch size and presence of goalkeepers on the work load of players during small-sided soccer games

Published Online: 02 Jul 2016
Page range: 175 - 181

Abstract

Abstract

Small-sided games (SSGs) are spontaneous forms of specific training where exercise intensity can be manipulated by modifying external factors. To ensure suitable usage of small-sided games in practice, we have to know which variables can influence internal responses and external loads. The aim of the present study was to determine the influence of presence of a goalkeeper and the pitch size on internal responses and the external load during five-a-side soccer games. Twenty nine junior soccer players (age: 18.11 ± 1.31 years; body mass index: 21.04 ± 2.58 kg·m-2; peak heart rate: 199.53 ± 7.51 beats·min–1) participated in the study. The heart rate, distance covered and the rate of perceived exertion were monitored. We found significantly higher average heart rates of players in 5v5 SSGs without goalkeepers than with them on a small pitch. Analysis showed significant differences in the time spent in 65-85% of the peak heart rate zone and ˂65% of the peak heart rate zone on the small pitch. Furthermore, we found significantly higher distance covered by players during five-a-side games with goalkeepers than without them played on the small pitch. Our results indicate that the pitch size is a very important variable that influences the work load of players. The inclusion of the goalkeeper decreases the work load of the player on a small pitch (28 × 20 m; 560 m2), but not on a medium or large pitch.

Key words

  • heart rate
  • distance covered
  • specificity
  • RPE
  • tactical metabolic training
Open Access

The oxygen uptake slow component at submaximal intensities in breaststroke swimming

Published Online: 02 Jul 2016
Page range: 165 - 173

Abstract

Abstract

The present work proposed to study the oxygen uptake slow component (VO2 SC) of breaststroke swimmers at four different intensities of submaximal exercise, via mathematical modeling of a multi-exponential function. The slow component (SC) was also assessed with two different fixed interval methods and the three methods were compared. Twelve male swimmers performed a test comprising four submaximal 300 m bouts at different intensities where all expired gases were collected breath by breath. Multi-exponential modeling showed values above 450 ml·min−1 of the SC in the two last bouts of exercise (those with intensities above the lactate threshold). A significant effect of the method that was used to calculate the VO2 SC was revealed. Higher mean values were observed when using mathematical modeling compared with the fixed interval 3rd min method (F=7.111; p=0.012; η2=0.587); furthermore, differences were detected among the two fixed interval methods. No significant relationship was found between the SC determined by any method and the blood lactate measured at each of the four exercise intensities. In addition, no significant association between the SC and peak oxygen uptake was found. It was concluded that in trained breaststroke swimmers, the presence of the VO2 SC may be observed at intensities above that corresponding to the 3.5 mM-1 threshold. Moreover, mathematical modeling of the oxygen uptake on-kinetics tended to show a higher slow component as compared to fixed interval methods.

Key words

  • VO on-kinetics
  • mathematical modeling
  • breaststroke swimming
Open Access

The influence of scoring targets and outer-floaters on attacking and defending team dispersion, shape and creation of space during small-sided soccer games

Published Online: 02 Jul 2016
Page range: 153 - 163

Abstract

Abstract

The effect of altered game formats on team performances during soccer practice can be harnessed by coaches to stimulate specific tactical behaviours. The aim of the present study was to analyse the influence of using (i) small goals [SG], (ii) goalkeepers [7G] and (iii) floaters [7GF] on the dispersion, shape and available space of teams during small-sided games (SSGs). Twenty-four male soccer players were distributed into four teams composed of five players, two goalkeepers and two floaters that performed six SSG bouts of 6 min, interspersed with 6 min of passive recovery. Offensive and defensive phases were also analysed separately in order to verify the preservation of basic principles of attacking (teams more stretched to create free space) and defending (teams more compact to tie-up space) during SSGs. The variables used to characterize the collective behaviour were: length [L], width [W], team shape [Sh], and team separateness [TS]. Results revealed that the teams showed different collective behaviours depending on SSG format and a playing phase: a) L and W were higher in attack than in defence in all SSGs; b) team shapes were more elongated in defence in all SSGs except SG; c) the space separating players from their closest opponents (TS) was shorter in 7G; and d) SG and 7GF elicited greater defensive openness due to increased team width. The results suggest that manipulating task constraints, such as goal size, presence or absence of goalkeepers and floaters can be harnessed by coaches to shape distinct team tactical behaviours in SSGs while preserving the basic principles of attacking and defending.

Key words

  • task constraints
  • tactical behaviours
  • GPS device
  • team sports
  • coaching
Open Access

The relative contribution of physical fitness to the technical execution score in youth rhythmic gymnastics

Published Online: 02 Jul 2016
Page range: 143 - 152

Abstract

Abstract

This study examined the association between physical fitness and a technical execution score in rhythmic gymnasts varying in the performance level. Forty-six young rhythmic gymnasts (age: 9.9 ±1.3 years) were divided into two groups (qualifiers, n=24 and non-qualifiers, n=22) based on the results of the National Championships. Gymnasts underwent a series of physical fitness tests and technical execution was evaluated in a routine without apparatus. There were significant differences between qualifiers and non-qualifiers in the technical execution score (p=0.01, d=1.0), shoulder flexion (p=0.01, d=0.8), straight leg raise (p=0.004, d=0.9), sideways leg extension (p=0.002, d=0.9) and body fat (p=.021, d=0.7), but no differences were found in muscular endurance and jumping performance. The technical execution score for the non-qualifiers was significantly correlated with shoulder extension (r=0.423, p<0.05), sideways leg extension (r=0.687, p<0.01), push ups (r=0.437, p<0.05) and body fat (r=0.642, p<0.01), while there was only one significant correlation with sideways leg extension (r=0.467, p<0.05) for the qualifiers. Multiple regression analysis revealed that sideways leg extension, body fat, and push ups accounted for a large part (62.9%) of the variance in the technical execution score for the non-qualifiers, while for the qualifiers, only 37.3% of the variance in the technical execution score was accounted for by sideways leg extension and spine flexibility. In conclusion, flexibility and body composition can effectively discriminate between qualifiers and non-qualifiers in youth rhythmic gymnastics. At the lower level of performance (non-qualifiers), physical fitness seems to have a greater effect on the technical execution score.

Key words

  • flexibility
  • body composition
  • gymnastics
Open Access

A new physical performance classification system for elite handball players: cluster analysis

Published Online: 02 Jul 2016
Page range: 131 - 142

Abstract

Abstract

The aim of the present study was to identify different cluster groups of handball players according to their physical performance level assessed in a series of physical assessments, which could then be used to design a training program based on individual strengths and weaknesses, and to determine which of these variables best identified elite performance in a group of under-19 [U19] national level handball players. Players of the U19 National Handball team (n=16) performed a set of tests to determine: 10 m (ST10) and 20 m (ST20) sprint time, ball release velocity (BRv), countermovement jump (CMJ) height and squat jump (SJ) height. All players also performed an incremental-load bench press test to determine the 1 repetition maximum (1RMest), the load corresponding to maximum mean power (LoadMP), the mean propulsive phase power at LoadMP (PMPPMP) and the peak power at LoadMP (PPEAKMP). Cluster analyses of the test results generated four groupings of players. The variables best able to discriminate physical performance were BRv, ST20, 1RMest, PPEAKMP and PMPPMP. These variables could help coaches identify talent or monitor the physical performance of athletes in their team. Each cluster of players has a particular weakness related to physical performance and therefore, the cluster results can be applied to a specific training programmed based on individual needs.

Key words

  • strength
  • sport
  • physical fitness
Open Access

Efficacy of the “pick and roll” offense in top level European basketball teams

Published Online: 02 Jul 2016
Page range: 121 - 129

Abstract

Abstract

Team offense in basketball games consists of a set of offensive actions carried out with the cooperation of two or more players. Of these actions, the most commonly used in the last decade is the on-ball screen called the “pick and roll.” The aim of this study was to analyze all of the pick and rolls conducted in the Euroleague championship from all of the 24 participating teams and to investigate the possible relationships between success in the pick and roll and overall success of the teams. For this purpose, 12,376 pick and rolls from 502 matches were analyzed and classified in categories according to the end result of the offensive possession. The results showed that the most effective type of pick and roll offense was when a shot was attempted after 2 passes from the pick and roll occurrence, followed by the screener’s shot when he rolled to the basket. Additionally, linear regression analysis confirmed that pick and roll effectiveness could predict the final classification of the teams. Conclusively, coaches of the high level European clubs should focus on training the players to the most efficient phases of the pick and roll offense, so that the chances of winning the championship to be maximized.

Key words

  • performance analysis
  • screen
  • offensive efficiency
  • basketball
Open Access

Sex differences and the effects of modified combat regulations on endurance capacity in judo athletes: A meta-analytic approach

Published Online: 02 Jul 2016
Page range: 113 - 120

Abstract

Abstract

Judo requires endurance capacity to recover from its high-intensity intermittent actions. This systematic review aimed to evaluate VO2max and the anaerobic threshold in competitive male and female judo athletes. Twelve eligible studies were chosen for quantitative meta-analysis, including results for 188 male and 159 female athletes. Combined values were calculated and compared by gender prior to and following altered combat regulations in 2003. No significant differences in VO2max were noted following the rule changes, but female athletes’ values increased to a level comparable to those reported in male athletes prior to the alterations. VO2max in male judo athletes was higher (54.8±1.9 ml·kg-1·min-1) than in female athletes (48.7±2.2 ml·kg-1·min-1). The effect size of gender was large (d = 1.30) for VO2max and negligible for the anaerobic threshold. Sexual dimorphism exists in VO2max of judo athletes and changes in combat duration did not affect these differences.

Key words

  • performance
  • aerobic fitness
  • gender
  • combat sports
Open Access

Body composition and bone mineral density of collegiate American football players

Published Online: 02 Jul 2016
Page range: 103 - 112

Abstract

Abstract

The aim of this study was to compare whole and segmental body composition and bone mineral density of collegiate American football players by playing positions. Forty collegiate American football players voluntarily participated in this study. Participants were categorized by playing positions into one of five categories i.e., defensive linemen, offensive linemen, defensive secondary players, offensive secondary players and receivers. Whole body composition and bone mineral density were measured by dual x-ray absorptiometry. Offensive and defensive linemen had higher body mass, a body mass index, lean mass and a fat mass index compared to the remaining three positions and a higher lean mass index compared to offensive secondary players and receivers. Offensive linemen had a higher body fat percentage and lower values of upper to lower lean mass than offensive and defensive secondary players and receivers, and higher total mass to the lean mass ratio and fat mass to the lean mass ratio compared to the other players. Offensive linemen had a higher fat mass index and fat mass to the lean mass ratio than defensive linemen. However, in all other measures they were similar. Offensive and defensive secondary players and receivers were similar with respect to the measured variables. Bone mineral density of the players was within the normal range and no difference in lean mass was observed between the legs. In conclusion, findings of this study showed that the total and segmental body composition profile of collegiate American football players reflected the demands of particular playing positions.

Key words

  • Dual x-ray absorptiometry
  • lean mass
  • fat mass
  • lean mass index
  • fat mass index
  • upper to lower lean mass ratio
Open Access

Intramuscular fiber conduction velocity, isometric force and explosive performance

Published Online: 02 Jul 2016
Page range: 93 - 101

Abstract

Abstract

Conduction of electrical signals along the surface of muscle fibers is acknowledged as an essential neuromuscular component which is linked with muscle force production. However, it remains unclear whether muscle fiber conduction velocity (MFCV) is also linked with explosive performance. The aim of the present study was to investigate the relationship between vastus lateralis MFCV and countermovement jumping performance, the rate of force development and maximum isometric force. Fifteen moderately-trained young females performed countermovement jumps as well as an isometric leg press test in order to determine the rate of force development and maximum isometric force. Vastus lateralis MFCV was measured with intramuscular microelectrodes at rest on a different occasion. Maximum MFCV was significantly correlated with maximum isometric force (r = 0.66, p < 0.01), nevertheless even closer with the leg press rate of force development at 100 ms, 150 ms, 200 ms, and 250 ms (r = 0.85, r = 0.89, r = 0.91, r = 0.92, respectively, p < 0.01). Similarly, mean MFCV and type II MFCV were better correlated with the rate of force development than with maximum isometric leg press force. Lower, but significant correlations were found between mean MFCV and countermovement jump power (r = 0.65, p < 0.01). These data suggest that muscle fiber conduction velocity is better linked with the rate of force development than with isometric force, perhaps because conduction velocity is higher in the larger and fastest muscle fibers which are recognized to contribute to explosive actions.

Key words

  • human muscle power
  • electromyography
  • electrical propagation velocity
  • muscle strength
Open Access

Physiological responses and match characteristics in professional tennis players during a one-hour simulated tennis match

Published Online: 02 Jul 2016
Page range: 83 - 92

Abstract

Abstract

The purpose of this study was to investigate the effects of serve and return game situations on physiological responses and match characteristics in professional male tennis players during one hour-long simulated singles tennis matches. Ten internationally ranked tennis players (age 22.2 ± 2.8 years; body height 180.7 ± 4.4 cm; body mass 75.9 ± 8.9 kg) participated in this study. Their physiological responses were measured using two portable analyzers during indoor hard court matches. Ratings of perceived exertion were also determined at the end of the game. The variables describing the characteristics of the matches determined from video recordings were: (a) duration of rallies; (b) rest time; (c) work-to-rest ratio; (d) effective playing time; and (d) strokes per rally. Significant differences (p<0.05) were found between serving and returning conditions in an hour-long simulated singles tennis match in terms of oxygen uptake, a heart rate, ratings of perceived exertion, pulmonary ventilation, respiration frequency and a respiratory gas exchange ratio. In addition, both the heart rate and ratings of perceived exertion responses were moderately correlated with the duration of rallies and strokes per rally (r = 0.60 to 0.26; p<0.05). Taken together, these results indicate that the serve game situation has a significant effect on the physiological response in an hour-long simulated tennis match between professional male tennis players. These findings might be used for the physiological adaptations required for tennis-specific aerobic endurance.

Key words

  • game-based training
  • performance analysis
  • racket sports
  • tennis match activity
Open Access

Changes of standard physiological-perceptual markers and circulating MicroRNAs in response to tennis match-play: A case report of two elite players

Published Online: 02 Jul 2016
Page range: 71 - 81

Abstract

Abstract

This study aimed to describe the acute changes of both standard physiological-perceptual markers and circulating microRNAs in response to tennis match-play in a detailed case report. Two elite male baseliners with comparable tennis experience were tested for anthropometric and fitness related variables and played 2 h of match-play on a red-clay court. The changes of standard physiological-perceptual markers including the heart rate, lactate concertation, creatine kinase activity, urea concentration and rating of perceived exertion as well as circulating microRNA-133a, -486 and -126 expression rates were examined at 10 different time-points (i.e., pre, during and up to 24 h post match-play). Player 2 had lower fitness related variables, but a higher heart rate, lactate concentration, creatine kinase activity and rating of perceived exertion during play than player 1. Player 2 showed an increase in all microRNAs (≤3.83-fold), most evident post match-play, whereas player 1 demonstrated a decrease (≤0.41-fold). The time-course in the changes of all standard physiological-perceptual markers was similar in both players, whereas this of the microRNAs was different. It was concluded that the relative changes of the circulating microRNA-133a, -486 and 126 expression rates of both players differed in response to tennis match-play with respect to the experienced physiological-perceptual stress and the underlying fitness level. Therefore, circulating microRNAs can serve as additional biomarkers for tennis exercise physiology and may be assessed together with standard markers to conclude whether key cellular regulatory processes were induced in response to match-play.

Key words

  • activity profile
  • gene expression
  • genetics
  • maximum oxygen uptake
  • training
  • testing
Open Access

The effect of the MTHFR C677T mutation on athletic performance and the homocysteine level of soccer players and sedentary individuals

Published Online: 02 Jul 2016
Page range: 61 - 69

Abstract

Abstract

This study investigated athletic performance and homocysteine (Hcy) levels in relation to the methylenetetrahydrofolate reductase (MTHFR) C677T mutation and explored the relationship between this mutation and other cardiac risk factors in soccer players and sedentary individuals. The study groups consisted of randomly selected soccer players (n=48) from the Turkish Super and Major League and sedentary male students (n=48) aged 18-27. Anthropometric variables, aerobic and anaerobic thresholds were measured, furthermore, biochemical assays were performed. The level of HDL cholesterol, LDL cholesterol, triglyceride, Hcy, folate, vitamin B12, hemogram and MTHFR C677T was investigated. The results showed that there was a statistical difference between the two groups in terms of body mass, body fat, the BMI, the aerobic threshold heart rate (ATHR), aerobic threshold velocity (ATVL) and anaerobic threshold velocity (ANTVL). The soccer players were found to have lower levels of triglyceride, total cholesterol and LDL cholesterol, and higher levels of folate than the sedentary participants. The analysis of the alleles of the MTHFR C677T polymorphism showed that the participants that carried TT genotypes had a lower level of vitamin B12 and folate, and a higher level of Hcy than the participants carrying CC and CT genotypes. In conclusion, the baseline homocysteine and cardiovascular fitness levels of healthy young males with the TT genotypes of the MTHFR C677T genotype were found to strongly correlate with their levels of Hcy.

Key words

  • MTHFR C677T
  • soccer
  • homocysteine
  • athletic performance
Open Access

The influence of the gait-related arm swing on elevation gain measured by sport watches

Published Online: 02 Jul 2016
Page range: 53 - 60

Abstract

Abstract

The elevation gain is an important contributor to the total workload in endurance sports. The purpose of this study was to evaluate the influence of the arm swing on elevation gain in three sport watches (Garmin® Forerunner 910XT, Polar® RS800CX and Suunto® Ambit2) on a flat 400 m outdoor track. Altogether, a total of 120 repetitions of 1,200 m were performed at self-selected speeds corresponding to strolling, walking, jogging and running. During the assessment two devices of each sport watch, one secured on the hip and one on the wrist, were worn by the participants. A small but significant (effect size = .39; p < .001) influence of the arm swing on elevation was revealed in all sport watches. Elevation indication errors recorded on the wrist were significantly larger than the ones recorded on the hip (4.0-7.4 vs. 1.2-5.7 m per 1,200 m; p < .05). Furthermore, when wearing the devices on the wrist, errors in elevation indication increased when gait speed increased. Users should be aware that wearing the devices on the hip can significantly decrease measurement errors. This might be especially relevant for activities with high dynamics, such as jogging and running.

Key words

  • workload
  • change in altitude
  • running
Open Access

Triathlon wetsuit removal strategy: physiological cost of running with a wetsuit

Published Online: 02 Jul 2016
Page range: 45 - 51

Abstract

Abstract

Triathletes exiting the swim portion of an event have to decide on how and when to take a wetsuit off (if worn). The purpose of this study was to determine the physiological cost of running while not using a wetsuit, carrying a wetsuit, wearing a wetsuit halfway down or wearing a wetsuit fully up. Participants (n = 20, 30.9 ± 8.7 yrs, 1.71 ± 0.08 m, 71.6 ± 9.5 kg) completed four 5 min running conditions: 1) not wearing the wetsuit, 2) wearing the wetsuit fully up, 3) wearing the wetsuit halfway down, and 4) carrying the wetsuit. A rate of oxygen uptake, a heart rate, ratings of perceived exertion and stride frequency were measured and were each influenced by wetsuit condition (p < 0.05). Each variable (i.e., a rate of oxygen uptake, a heart rate, stride frequency) was lower during running while not wearing the wetsuit vs. any other condition (p < 0.05). The rate of oxygen uptake was greatest during wearing the wetsuit halfway down vs. any other condition (p < 0.05). The heart rate was not different between any of the combinations of either wearing the wetsuit fully up or halfway down or carrying the wetsuit (p > 0.05). The rating of perceived exertion was greater during wearing the wetsuit halfway down vs. carrying the wetsuit (p < 0.05). Stride frequency was lower during not wearing the wetsuit vs. wearing the wetsuit halfway down or fully up (p < 0.05). It was concluded that running with the wetsuit halfway down resulted in the greatest rate of oxygen uptake, heart rate and rating of perceived exertion.

Key words

  • running economy
  • fatigue
  • race performance
Open Access

Relationships between movements of the lower limb joints and the pelvis in open and closed kinematic chains during a gait cycle

Published Online: 02 Jul 2016
Page range: 37 - 43

Abstract

Abstract

Lots of athletic skills performed during practice or competition are initiated by the legs, where athletes either walk or run prior to executing specific skills. Kinematic chains are used to describe the relationships between body segments and joints during movement. The aim of this study was to determine the relationships between movements of lower limb segments and the pelvis in open and closed kinematic chains while walking. The experimental group consisted of 32 males (age 23.3 ± 2.5 years, body mass 78.1 ± 8.7 kg, body height 182 ± 6 cm). For 3D analysis, an optoelectronic system Vicon MX (7 cameras, frequency 200 Hz) was used. Positioning of the segments was determined by the PlugInGait Model. Each participant executed five trials at speeds ranging from 1.38 to 1.52 m·s-1. The relationships between angle variables of the lower limbs and the pelvis in selected gait cycle phases were evaluated using STATISTICA software (version 10.0) and the Spearman correlation. The highest numbers of moderate and large correlations were found at opposite toe off, heel rise and initial contact for the sagittal and transversal planes in comparison to the frontal plane. The closed kinematic chain had a stronger impact on determining the movement pattern. The instructions or interventions focusing on closed kinematic chain alternation are more effective for changes in a movement pattern. The preferred limb initiates kinematics in the direction of propulsion, while the non-preferred limb in internal and external rotation.

Key words

  • walking
  • coupling
  • intra-limb
  • coordination
Open Access

The effect of exercise intensity on cognitive performance during short duration treadmill running

Published Online: 02 Jul 2016
Page range: 27 - 35

Abstract

Abstract

This study examined the effect of short duration, moderate and high-intensity exercise on a Go/NoGo task. Fifteen, habitually active (9 females and 6 males aged 28 ± 5 years) agreed to participate in the study and cognitive performance was measured in three sessions lasting 10 min each, performed at three different exercise intensities: rest, moderate and high. Results indicated significant exercise intensity main effects for reaction time (RT) (p = 0.01), the omission error rate (p = 0.027) and the decision error rate (p = 0.011), with significantly longer RTs during high intensity exercise compared to moderate intensity exercise (p = 0.039) and rest (p = 0.023). Mean ± SE of RT (ms) was 395.8 ± 9.1, 396.3 ± 9.1 and 433.5 ± 16.1 for rest, moderate and high intensity exercise, respectively. This pattern was replicated for the error rate with a significantly higher omission error and decision error rate during high intensity exercise compared to moderate intensity exercise (p = 0.003) and rest (p = 0.001). Mean ± SE of omission errors (%) was 0.88 ± 0.23, 0.8 ± 0.23 and 1.8 ± 0.46% for rest, moderate and high intensity exercise, respectively. Likewise, mean ± SE of decision errors (%) was 0.73 ± 0.24, 0.73 ± 0.21 and 1.8 ± 0.31 for rest, moderate and high intensity exercise, respectively. The present study’s results suggest that 10 min workout at high intensity impairs RT performances in habitually active adults compared to rest or moderate intensity exercise.

Key words

  • Go/No-go task
  • Reaction Time
  • Response Inhibition
Open Access

Evaluating injury risk in first and second league professional Portuguese soccer: muscular strength and asymmetry

Published Online: 02 Jul 2016
Page range: 19 - 26

Abstract

Abstract

Strength imbalances between the hamstrings and quadriceps are an essential predictor for hamstring strain in soccer. The study aimed to investigate and compare the muscle strength imbalances of professional soccer players of different performance levels. One hundred and fifty nine senior male professional soccer players from first (n = 75) and second league (n = 84) Portuguese clubs participated in this study. Muscle strength was evaluated with a REV9000 isokinetic dynamometer. Maximal peak torque data were used to calculate quadriceps and hamstrings strength during concentric and eccentric actions, bilateral asymmetry, conventional strength ratios and dynamic control ratios. Second league athletes produced slightly lower conventional strength ratios in the right and left legs (ES = 0.22, p = 0.17 and ES = 0.36, p = 0.023, respectively) compared to the first league athletes. No significant differences were found in dynamic control ratios or in bilateral asymmetry among first and second league athletes. These findings do not show a clear link between the competitive level and injury risk in soccer players. However, some of the differences found, particularly in conventional strength ratios, highlight the importance of performing off-season and pre-season strength assessments to prescribe and adjust individual strength training programs among professional soccer players.

Key words

  • dynamometry
  • isokinetic strength
  • H:Q ratios
  • muscle imbalances
Open Access

Chunk concatenation evolves with practice and sleep-related enhancement consolidation in a complex arm movement sequence

Published Online: 02 Jul 2016
Page range: 5 - 17

Abstract

Abstract

This paper addresses the notion of chunk concatenation being associated with sleep-related enhancement consolidation of motor sequence memory, thereby essentially contributing to improvements in sequence execution speed. To this end, element movement times of a multi-joint arm movement sequence incorporated in a recent study by Malangré et al. (2014) were reanalyzed. As sequence elements differed with respect to movement distance, element movement times had to be purged from differences solely due to varying trajectory lengths. This was done by dividing each element movement time per subject and trial block by the respective “reference movement time” collected from subjects who had extensively practiced each sequence element in isolation. Any differences in these “relative element movement times” were supposed to reflect element-specific “production costs” imposed solely by the sequence context. Across all subjects non-idiosyncratic, lasting sequence segmentation was shown, and four possible concatenation points (i.e. transition points between successive chunks) within the original arm movement sequence were identified. Based on theoretical suppositions derived from previous work with the discrete sequence production task and the dual processor model (Abrahamse et al., 2013), significantly larger improvements in transition speed occurring at these four concatenation points as compared to the five fastest transition positions within the sequence (associated with mere element execution) were assumed to indicate increased chunk concatenation. As a result, chunk concatenation was shown to proceed during acquisition with physical practice, and, most importantly, to significantly progress some more during retention following a night of sleep, but not during a waking interval.

Key words

  • motor sequence learning
  • memory consolidation
  • offline learning
  • sleep
  • gross motor skill
26 Articles

Research Article

Open Access

An investigation into the relationship between pre-competition mood states, age, gender and a national ranking in artistic gymnastics

Published Online: 02 Jul 2016
Page range: 243 - 252

Abstract

Abstract

This study investigated the relationship between pre-competition mood state factors in gymnastics by gender, age and a national ranking. Participant-gymnasts (total n=116, male n=49, female n=67) completed a Brunel Mood Scale (BRUMS) one day prior to their main competition of the year. Information was also gathered from gymnasts of gender, age and a national ranking. Consistent with theoretical predictions, results confirmed that a number of pre-competition mood states differed by age with both juniors and seniors having a higher level of anger than children (p<.05 respectively). Also, seniors demonstrated higher tension than children (p<.001). However, only anger showed significant differences by gender with male gymnasts demonstrating higher levels of anger than female gymnasts (p<.05), and with international gymnasts registering higher levels of anger compared with second class gymnasts (p<.05). Authors suggest that future research should investigate relationships between the pre-competition mood in other gymnastics-related disciplines and sports, as well as competitive performances.

Key words

  • pre-competition mood states
  • national ranking
  • artistic gymnastics
Open Access

Determinants of feedback retention in soccer players

Published Online: 02 Jul 2016
Page range: 235 - 241

Abstract

Abstract

This study analyzed soccer players’ retention of coaches’ feedback during training sessions. We intended to determine if the retention of information was influenced by the athletes’ personal characteristic (age, gender and the sports level), the quantity of information included in coach’s feedback (the number of ideas and redundancy), athletes’ perception of the relevance of the feedback information and athletes’ motivation as well as the attention level. The study that was conducted over the course of 18 sessions of soccer practice, involved 12 coaches (8 males, 4 females) and 342 athletes (246 males, 96 females), aged between 10 and 18 years old. All coach and athlete interventions were transposed to a written protocol and submitted to content analysis. Descriptive statistics and multiple linear regression were calculated. The results showed that a substantial part of the information was not retained by the athletes; in 65.5% of cases, athletes experienced difficulty in completely reproducing the ideas of the coaches and, on average, the value of feedback retention was 57.0%. Six variables with a statistically significant value were found: gender, the athletes’ sports level, redundancy, the number of transmitted ideas, athletes’ perception of the relevance of the feedback information and the athletes’ motivation level.

Key words

  • Soccer players
  • coach feedback
  • information retention
  • motivation and attention level
Open Access

Conforming and nonconforming personality and stress coping styles in combat athletes

Published Online: 02 Jul 2016
Page range: 225 - 233

Abstract

Abstract

The main objective of this study was to investigate whether the personality dimension of conformism/nonconformism was a predictor of stress coping styles in athletes training combat sports, and to present the characteristics of this personality dimension in the context of the competitors’ adaptive/innovative sport performance. Scores of 346 males practising combat sports such as kick boxing, MMA, thai boxing, boxing and wrestling were analyzed. The participants completed the Creative Behaviour Questionnaire (KANH III) measuring the conformity/nonconformity personality dimension and the Coping Inventory for Stressful Situations (CISS) measuring stress coping styles. The comparative analyses were conducted only for the groups of conformists and nonconformists. Differences in stress coping styles between conformists and nonconformists training combat sports were found as nonconformists tended to prefer the task-oriented coping style. Conclusively, a higher rate of nonconformity was associated with increasingly frequent occurrence of task-oriented coping and decreasingly frequent emotion-oriented coping.

Key words

  • combat sports
  • conformism
  • coping styles
  • nonconformism
  • personality
  • stress
Open Access

The goalkeeper influence on ball possession effectiveness in futsal

Published Online: 02 Jul 2016
Page range: 217 - 224

Abstract

Abstract

The aim of this study was to identify which variables were the best predictors of success in futsal ball possession when controlling for space and task related indicators, situational variables and the participation of the goalkeeper as a regular field player or not (5 vs. 4 or 4 vs. 4). The sample consisted of 326 situations of ball possession corresponding to 31 matches played by a team from the Spanish Futsal League during the 2010–2011, 2011–2012 and 2012–2013 seasons. Multidimensional qualitative data obtained from 10 ordered categorical variables were used. Data were analysed using chi-square analysis and multiple logistic regression analysis. Overall, the highest ball possession effectiveness was achieved when the goalkeeper participated as a regular field player (p<0.01), the duration of the ball possession was less than 10 s (p<0.01), the ball possession ended in the penalty area (p<0.01) and the defensive pressure was low (p<0.01). The information obtained on the relative effectiveness of offensive playing tactics can be used to improve team’s goal-scoring and goal preventing abilities.

Key words

  • performance analysis
  • offensive performance
  • logistic regression
  • goalkeeper
Open Access

Effects of ethnicity on the relationship between vertical jump and maximal power on a cycle ergometer

Published Online: 02 Jul 2016
Page range: 209 - 216

Abstract

Abstract

The aim of this study was to verify the impact of ethnicity on the maximal power-vertical jump relationship. Thirty-one healthy males, sixteen Caucasian (age: 26.3 ± 3.5 years; body height: 179.1 ± 5.5 cm; body mass: 78.1 ± 9.8 kg) and fifteen Afro-Caribbean (age: 24.4 ±2.6 years; body height: 178.9 ± 5.5 cm; body mass: 77.1 ± 10.3 kg) completed three sessions during which vertical jump height and maximal power of lower limbs were measured. The results showed that the values of vertical jump height and maximal power were higher for Afro-Caribbean participants (62.92 ± 6.7 cm and 14.70 ± 1.75 W∙kg-1) than for Caucasian ones (52.92 ± 4.4 cm and 12.75 ± 1.36 W∙kg-1). Moreover, very high reliability indices were obtained on vertical jump (e.g. 0.95 < ICC < 0.98) and maximal power performance (e.g. 0.75 < ICC < 0.97). However, multiple linear regression analysis showed that, for a given value of maximal power, the Afro-Caribbean participants jumped 8 cm higher than the Caucasians. Together, these results confirmed that ethnicity impacted the maximal power-vertical jump relationship over three sessions. In the current context of cultural diversity, the use of vertical jump performance as a predictor of muscular power should be considered with caution when dealing with populations of different ethnic origins.

Key words

  • power output
  • cycling
  • practice effect
  • reliability
  • ethnicity
Open Access

Physical fitness and performance of polish ice-hockey players competing at different sports levels

Published Online: 02 Jul 2016
Page range: 201 - 208

Abstract

Abstract

The study aimed to determine the values of selected aerobic and anaerobic capacity variables, physical profiles, and to analyze the results of on-ice tests performed by ice-hockey players relegated to a lower league. Performance of 24 ice-hockey players competing in the top league in the 2012/2013 season was analysed to this end. In the 2013/2014 season, 14 of them still played in the top league (the control group), while 10 played in the first league (the experimental group). The study was conducted one week after the end of the playoffs in the seasons under consideration. The results revealed that only in the experimental group the analysed variables changed significantly between the seasons. In the Wingate test, significant changes were only noted in mean relative power (a decrease from 9.91 to 9.14 W/kg; p=0.045) and relative total work (a decrease from 299.17 to 277.22 J/kg; p=0.048). The ramp test indicated significantly lower power output in its final stages (364 compared with 384 W; p=0.034), as well as a significant decrease in relative VO2max (from 52.70 to 48.30 ml/min/kg). Blood lactate concentrations were recorded at the 3rd, 6th, 9th and 12th min of recovery after the ramp test. The rate of post-exercise recovery, ∆LA, recorded after the ramp test turned out to be significantly lower. The times recorded in the on-ice “6x30 m stop” test increased from 32.18 to 33.10 s (p=0.047). The study showed that playing in a lower league where games were less intensive, training sessions shorter and less frequent, had an adverse effect on the performance level of the investigated players. Lower VO2max recorded in the study participants slowed down their rates of post-exercise recovery and led to a significantly worse performance in the 6x30 m stop test, as well as lower relative power and relative total work in the Wingate test.

Key words

  • team sports
  • recovery
  • on-ice tests
  • aerobic capacity
  • anaerobic capacity
Open Access

10 km running performance predicted by a multiple linear regression model with allometrically adjusted variables

Published Online: 02 Jul 2016
Page range: 193 - 200

Abstract

Abstract

The aim of this study was to verify the power of VO2max, peak treadmill running velocity (PTV), and running economy (RE), unadjusted or allometrically adjusted, in predicting 10 km running performance. Eighteen male endurance runners performed: 1) an incremental test to exhaustion to determine VO2max and PTV; 2) a constant submaximal run at 12 km·h−1 on an outdoor track for RE determination; and 3) a 10 km running race. Unadjusted (VO2max, PTV and RE) and adjusted variables (VO2max0.72, PTV0.72 and RE0.60) were investigated through independent multiple regression models to predict 10 km running race time. There were no significant correlations between 10 km running time and either the adjusted or unadjusted VO2max. Significant correlations (p < 0.01) were found between 10 km running time and adjusted and unadjusted RE and PTV, providing models with effect size > 0.84 and power > 0.88. The allometrically adjusted predictive model was composed of PTV0.72 and RE0.60 and explained 83% of the variance in 10 km running time with a standard error of the estimate (SEE) of 1.5 min. The unadjusted model composed of a single PVT accounted for 72% of the variance in 10 km running time (SEE of 1.9 min). Both regression models provided powerful estimates of 10 km running time; however, the unadjusted PTV may provide an uncomplicated estimation.

Key words

  • VO
  • peak of treadmill velocity
  • running economy
  • allometry
Open Access

Comparison between two types of anaerobic speed endurance training in competitive soccer players

Published Online: 02 Jul 2016
Page range: 183 - 192

Abstract

Abstract

The purpose of the present study was to examine the effects of additional in-season speed endurance production versus speed endurance maintenance training regimes on performance in competitive male soccer players. In a randomised controlled trial 18 male sub-elite players were exposed to additional speed endurance production (SEP) or speed endurance maintenance (SEM) training (two additional sessions/wk for 4 weeks) during the competitive season. Players performed the Yo-Yo intermittent recovery level 2 test (YYIR2) and a repeated sprint test (RST) pre- and post-intervention. Yo-Yo IR2 performance increased (p<0.001) by 50 ± 8% and 26 ± 5% in SEP and SEM, respectively, with greater (p=0.03) improvement in SEP. RST performance improved by 2.1 ± 0.3% and 1.3 ± 0.4% in SEP and SEM, respectively, while the RST fatigue index decreased (4.4 ± 0.8 to 3.4 ± 0.5%; p<0.04) in SEP only. Peak and average speed during training were higher (p<0.001) in SEP than in SEM (24.5 ± 0.3 vs 19.2 ± 0.3 and 15.5 ± 0.1 km·h-1 vs 9.4 ± 0.1 km·h-1). Additional in-season anaerobic speed endurance production and maintenance training improves high-intensity exercise performance in competitive soccer players with superior effects of speed endurance production training.

Key words

  • adaptation effects
  • exercise testing
  • GPS
  • football
Open Access

Effect of the pitch size and presence of goalkeepers on the work load of players during small-sided soccer games

Published Online: 02 Jul 2016
Page range: 175 - 181

Abstract

Abstract

Small-sided games (SSGs) are spontaneous forms of specific training where exercise intensity can be manipulated by modifying external factors. To ensure suitable usage of small-sided games in practice, we have to know which variables can influence internal responses and external loads. The aim of the present study was to determine the influence of presence of a goalkeeper and the pitch size on internal responses and the external load during five-a-side soccer games. Twenty nine junior soccer players (age: 18.11 ± 1.31 years; body mass index: 21.04 ± 2.58 kg·m-2; peak heart rate: 199.53 ± 7.51 beats·min–1) participated in the study. The heart rate, distance covered and the rate of perceived exertion were monitored. We found significantly higher average heart rates of players in 5v5 SSGs without goalkeepers than with them on a small pitch. Analysis showed significant differences in the time spent in 65-85% of the peak heart rate zone and ˂65% of the peak heart rate zone on the small pitch. Furthermore, we found significantly higher distance covered by players during five-a-side games with goalkeepers than without them played on the small pitch. Our results indicate that the pitch size is a very important variable that influences the work load of players. The inclusion of the goalkeeper decreases the work load of the player on a small pitch (28 × 20 m; 560 m2), but not on a medium or large pitch.

Key words

  • heart rate
  • distance covered
  • specificity
  • RPE
  • tactical metabolic training
Open Access

The oxygen uptake slow component at submaximal intensities in breaststroke swimming

Published Online: 02 Jul 2016
Page range: 165 - 173

Abstract

Abstract

The present work proposed to study the oxygen uptake slow component (VO2 SC) of breaststroke swimmers at four different intensities of submaximal exercise, via mathematical modeling of a multi-exponential function. The slow component (SC) was also assessed with two different fixed interval methods and the three methods were compared. Twelve male swimmers performed a test comprising four submaximal 300 m bouts at different intensities where all expired gases were collected breath by breath. Multi-exponential modeling showed values above 450 ml·min−1 of the SC in the two last bouts of exercise (those with intensities above the lactate threshold). A significant effect of the method that was used to calculate the VO2 SC was revealed. Higher mean values were observed when using mathematical modeling compared with the fixed interval 3rd min method (F=7.111; p=0.012; η2=0.587); furthermore, differences were detected among the two fixed interval methods. No significant relationship was found between the SC determined by any method and the blood lactate measured at each of the four exercise intensities. In addition, no significant association between the SC and peak oxygen uptake was found. It was concluded that in trained breaststroke swimmers, the presence of the VO2 SC may be observed at intensities above that corresponding to the 3.5 mM-1 threshold. Moreover, mathematical modeling of the oxygen uptake on-kinetics tended to show a higher slow component as compared to fixed interval methods.

Key words

  • VO on-kinetics
  • mathematical modeling
  • breaststroke swimming
Open Access

The influence of scoring targets and outer-floaters on attacking and defending team dispersion, shape and creation of space during small-sided soccer games

Published Online: 02 Jul 2016
Page range: 153 - 163

Abstract

Abstract

The effect of altered game formats on team performances during soccer practice can be harnessed by coaches to stimulate specific tactical behaviours. The aim of the present study was to analyse the influence of using (i) small goals [SG], (ii) goalkeepers [7G] and (iii) floaters [7GF] on the dispersion, shape and available space of teams during small-sided games (SSGs). Twenty-four male soccer players were distributed into four teams composed of five players, two goalkeepers and two floaters that performed six SSG bouts of 6 min, interspersed with 6 min of passive recovery. Offensive and defensive phases were also analysed separately in order to verify the preservation of basic principles of attacking (teams more stretched to create free space) and defending (teams more compact to tie-up space) during SSGs. The variables used to characterize the collective behaviour were: length [L], width [W], team shape [Sh], and team separateness [TS]. Results revealed that the teams showed different collective behaviours depending on SSG format and a playing phase: a) L and W were higher in attack than in defence in all SSGs; b) team shapes were more elongated in defence in all SSGs except SG; c) the space separating players from their closest opponents (TS) was shorter in 7G; and d) SG and 7GF elicited greater defensive openness due to increased team width. The results suggest that manipulating task constraints, such as goal size, presence or absence of goalkeepers and floaters can be harnessed by coaches to shape distinct team tactical behaviours in SSGs while preserving the basic principles of attacking and defending.

Key words

  • task constraints
  • tactical behaviours
  • GPS device
  • team sports
  • coaching
Open Access

The relative contribution of physical fitness to the technical execution score in youth rhythmic gymnastics

Published Online: 02 Jul 2016
Page range: 143 - 152

Abstract

Abstract

This study examined the association between physical fitness and a technical execution score in rhythmic gymnasts varying in the performance level. Forty-six young rhythmic gymnasts (age: 9.9 ±1.3 years) were divided into two groups (qualifiers, n=24 and non-qualifiers, n=22) based on the results of the National Championships. Gymnasts underwent a series of physical fitness tests and technical execution was evaluated in a routine without apparatus. There were significant differences between qualifiers and non-qualifiers in the technical execution score (p=0.01, d=1.0), shoulder flexion (p=0.01, d=0.8), straight leg raise (p=0.004, d=0.9), sideways leg extension (p=0.002, d=0.9) and body fat (p=.021, d=0.7), but no differences were found in muscular endurance and jumping performance. The technical execution score for the non-qualifiers was significantly correlated with shoulder extension (r=0.423, p<0.05), sideways leg extension (r=0.687, p<0.01), push ups (r=0.437, p<0.05) and body fat (r=0.642, p<0.01), while there was only one significant correlation with sideways leg extension (r=0.467, p<0.05) for the qualifiers. Multiple regression analysis revealed that sideways leg extension, body fat, and push ups accounted for a large part (62.9%) of the variance in the technical execution score for the non-qualifiers, while for the qualifiers, only 37.3% of the variance in the technical execution score was accounted for by sideways leg extension and spine flexibility. In conclusion, flexibility and body composition can effectively discriminate between qualifiers and non-qualifiers in youth rhythmic gymnastics. At the lower level of performance (non-qualifiers), physical fitness seems to have a greater effect on the technical execution score.

Key words

  • flexibility
  • body composition
  • gymnastics
Open Access

A new physical performance classification system for elite handball players: cluster analysis

Published Online: 02 Jul 2016
Page range: 131 - 142

Abstract

Abstract

The aim of the present study was to identify different cluster groups of handball players according to their physical performance level assessed in a series of physical assessments, which could then be used to design a training program based on individual strengths and weaknesses, and to determine which of these variables best identified elite performance in a group of under-19 [U19] national level handball players. Players of the U19 National Handball team (n=16) performed a set of tests to determine: 10 m (ST10) and 20 m (ST20) sprint time, ball release velocity (BRv), countermovement jump (CMJ) height and squat jump (SJ) height. All players also performed an incremental-load bench press test to determine the 1 repetition maximum (1RMest), the load corresponding to maximum mean power (LoadMP), the mean propulsive phase power at LoadMP (PMPPMP) and the peak power at LoadMP (PPEAKMP). Cluster analyses of the test results generated four groupings of players. The variables best able to discriminate physical performance were BRv, ST20, 1RMest, PPEAKMP and PMPPMP. These variables could help coaches identify talent or monitor the physical performance of athletes in their team. Each cluster of players has a particular weakness related to physical performance and therefore, the cluster results can be applied to a specific training programmed based on individual needs.

Key words

  • strength
  • sport
  • physical fitness
Open Access

Efficacy of the “pick and roll” offense in top level European basketball teams

Published Online: 02 Jul 2016
Page range: 121 - 129

Abstract

Abstract

Team offense in basketball games consists of a set of offensive actions carried out with the cooperation of two or more players. Of these actions, the most commonly used in the last decade is the on-ball screen called the “pick and roll.” The aim of this study was to analyze all of the pick and rolls conducted in the Euroleague championship from all of the 24 participating teams and to investigate the possible relationships between success in the pick and roll and overall success of the teams. For this purpose, 12,376 pick and rolls from 502 matches were analyzed and classified in categories according to the end result of the offensive possession. The results showed that the most effective type of pick and roll offense was when a shot was attempted after 2 passes from the pick and roll occurrence, followed by the screener’s shot when he rolled to the basket. Additionally, linear regression analysis confirmed that pick and roll effectiveness could predict the final classification of the teams. Conclusively, coaches of the high level European clubs should focus on training the players to the most efficient phases of the pick and roll offense, so that the chances of winning the championship to be maximized.

Key words

  • performance analysis
  • screen
  • offensive efficiency
  • basketball
Open Access

Sex differences and the effects of modified combat regulations on endurance capacity in judo athletes: A meta-analytic approach

Published Online: 02 Jul 2016
Page range: 113 - 120

Abstract

Abstract

Judo requires endurance capacity to recover from its high-intensity intermittent actions. This systematic review aimed to evaluate VO2max and the anaerobic threshold in competitive male and female judo athletes. Twelve eligible studies were chosen for quantitative meta-analysis, including results for 188 male and 159 female athletes. Combined values were calculated and compared by gender prior to and following altered combat regulations in 2003. No significant differences in VO2max were noted following the rule changes, but female athletes’ values increased to a level comparable to those reported in male athletes prior to the alterations. VO2max in male judo athletes was higher (54.8±1.9 ml·kg-1·min-1) than in female athletes (48.7±2.2 ml·kg-1·min-1). The effect size of gender was large (d = 1.30) for VO2max and negligible for the anaerobic threshold. Sexual dimorphism exists in VO2max of judo athletes and changes in combat duration did not affect these differences.

Key words

  • performance
  • aerobic fitness
  • gender
  • combat sports
Open Access

Body composition and bone mineral density of collegiate American football players

Published Online: 02 Jul 2016
Page range: 103 - 112

Abstract

Abstract

The aim of this study was to compare whole and segmental body composition and bone mineral density of collegiate American football players by playing positions. Forty collegiate American football players voluntarily participated in this study. Participants were categorized by playing positions into one of five categories i.e., defensive linemen, offensive linemen, defensive secondary players, offensive secondary players and receivers. Whole body composition and bone mineral density were measured by dual x-ray absorptiometry. Offensive and defensive linemen had higher body mass, a body mass index, lean mass and a fat mass index compared to the remaining three positions and a higher lean mass index compared to offensive secondary players and receivers. Offensive linemen had a higher body fat percentage and lower values of upper to lower lean mass than offensive and defensive secondary players and receivers, and higher total mass to the lean mass ratio and fat mass to the lean mass ratio compared to the other players. Offensive linemen had a higher fat mass index and fat mass to the lean mass ratio than defensive linemen. However, in all other measures they were similar. Offensive and defensive secondary players and receivers were similar with respect to the measured variables. Bone mineral density of the players was within the normal range and no difference in lean mass was observed between the legs. In conclusion, findings of this study showed that the total and segmental body composition profile of collegiate American football players reflected the demands of particular playing positions.

Key words

  • Dual x-ray absorptiometry
  • lean mass
  • fat mass
  • lean mass index
  • fat mass index
  • upper to lower lean mass ratio
Open Access

Intramuscular fiber conduction velocity, isometric force and explosive performance

Published Online: 02 Jul 2016
Page range: 93 - 101

Abstract

Abstract

Conduction of electrical signals along the surface of muscle fibers is acknowledged as an essential neuromuscular component which is linked with muscle force production. However, it remains unclear whether muscle fiber conduction velocity (MFCV) is also linked with explosive performance. The aim of the present study was to investigate the relationship between vastus lateralis MFCV and countermovement jumping performance, the rate of force development and maximum isometric force. Fifteen moderately-trained young females performed countermovement jumps as well as an isometric leg press test in order to determine the rate of force development and maximum isometric force. Vastus lateralis MFCV was measured with intramuscular microelectrodes at rest on a different occasion. Maximum MFCV was significantly correlated with maximum isometric force (r = 0.66, p < 0.01), nevertheless even closer with the leg press rate of force development at 100 ms, 150 ms, 200 ms, and 250 ms (r = 0.85, r = 0.89, r = 0.91, r = 0.92, respectively, p < 0.01). Similarly, mean MFCV and type II MFCV were better correlated with the rate of force development than with maximum isometric leg press force. Lower, but significant correlations were found between mean MFCV and countermovement jump power (r = 0.65, p < 0.01). These data suggest that muscle fiber conduction velocity is better linked with the rate of force development than with isometric force, perhaps because conduction velocity is higher in the larger and fastest muscle fibers which are recognized to contribute to explosive actions.

Key words

  • human muscle power
  • electromyography
  • electrical propagation velocity
  • muscle strength
Open Access

Physiological responses and match characteristics in professional tennis players during a one-hour simulated tennis match

Published Online: 02 Jul 2016
Page range: 83 - 92

Abstract

Abstract

The purpose of this study was to investigate the effects of serve and return game situations on physiological responses and match characteristics in professional male tennis players during one hour-long simulated singles tennis matches. Ten internationally ranked tennis players (age 22.2 ± 2.8 years; body height 180.7 ± 4.4 cm; body mass 75.9 ± 8.9 kg) participated in this study. Their physiological responses were measured using two portable analyzers during indoor hard court matches. Ratings of perceived exertion were also determined at the end of the game. The variables describing the characteristics of the matches determined from video recordings were: (a) duration of rallies; (b) rest time; (c) work-to-rest ratio; (d) effective playing time; and (d) strokes per rally. Significant differences (p<0.05) were found between serving and returning conditions in an hour-long simulated singles tennis match in terms of oxygen uptake, a heart rate, ratings of perceived exertion, pulmonary ventilation, respiration frequency and a respiratory gas exchange ratio. In addition, both the heart rate and ratings of perceived exertion responses were moderately correlated with the duration of rallies and strokes per rally (r = 0.60 to 0.26; p<0.05). Taken together, these results indicate that the serve game situation has a significant effect on the physiological response in an hour-long simulated tennis match between professional male tennis players. These findings might be used for the physiological adaptations required for tennis-specific aerobic endurance.

Key words

  • game-based training
  • performance analysis
  • racket sports
  • tennis match activity
Open Access

Changes of standard physiological-perceptual markers and circulating MicroRNAs in response to tennis match-play: A case report of two elite players

Published Online: 02 Jul 2016
Page range: 71 - 81

Abstract

Abstract

This study aimed to describe the acute changes of both standard physiological-perceptual markers and circulating microRNAs in response to tennis match-play in a detailed case report. Two elite male baseliners with comparable tennis experience were tested for anthropometric and fitness related variables and played 2 h of match-play on a red-clay court. The changes of standard physiological-perceptual markers including the heart rate, lactate concertation, creatine kinase activity, urea concentration and rating of perceived exertion as well as circulating microRNA-133a, -486 and -126 expression rates were examined at 10 different time-points (i.e., pre, during and up to 24 h post match-play). Player 2 had lower fitness related variables, but a higher heart rate, lactate concentration, creatine kinase activity and rating of perceived exertion during play than player 1. Player 2 showed an increase in all microRNAs (≤3.83-fold), most evident post match-play, whereas player 1 demonstrated a decrease (≤0.41-fold). The time-course in the changes of all standard physiological-perceptual markers was similar in both players, whereas this of the microRNAs was different. It was concluded that the relative changes of the circulating microRNA-133a, -486 and 126 expression rates of both players differed in response to tennis match-play with respect to the experienced physiological-perceptual stress and the underlying fitness level. Therefore, circulating microRNAs can serve as additional biomarkers for tennis exercise physiology and may be assessed together with standard markers to conclude whether key cellular regulatory processes were induced in response to match-play.

Key words

  • activity profile
  • gene expression
  • genetics
  • maximum oxygen uptake
  • training
  • testing
Open Access

The effect of the MTHFR C677T mutation on athletic performance and the homocysteine level of soccer players and sedentary individuals

Published Online: 02 Jul 2016
Page range: 61 - 69

Abstract

Abstract

This study investigated athletic performance and homocysteine (Hcy) levels in relation to the methylenetetrahydrofolate reductase (MTHFR) C677T mutation and explored the relationship between this mutation and other cardiac risk factors in soccer players and sedentary individuals. The study groups consisted of randomly selected soccer players (n=48) from the Turkish Super and Major League and sedentary male students (n=48) aged 18-27. Anthropometric variables, aerobic and anaerobic thresholds were measured, furthermore, biochemical assays were performed. The level of HDL cholesterol, LDL cholesterol, triglyceride, Hcy, folate, vitamin B12, hemogram and MTHFR C677T was investigated. The results showed that there was a statistical difference between the two groups in terms of body mass, body fat, the BMI, the aerobic threshold heart rate (ATHR), aerobic threshold velocity (ATVL) and anaerobic threshold velocity (ANTVL). The soccer players were found to have lower levels of triglyceride, total cholesterol and LDL cholesterol, and higher levels of folate than the sedentary participants. The analysis of the alleles of the MTHFR C677T polymorphism showed that the participants that carried TT genotypes had a lower level of vitamin B12 and folate, and a higher level of Hcy than the participants carrying CC and CT genotypes. In conclusion, the baseline homocysteine and cardiovascular fitness levels of healthy young males with the TT genotypes of the MTHFR C677T genotype were found to strongly correlate with their levels of Hcy.

Key words

  • MTHFR C677T
  • soccer
  • homocysteine
  • athletic performance
Open Access

The influence of the gait-related arm swing on elevation gain measured by sport watches

Published Online: 02 Jul 2016
Page range: 53 - 60

Abstract

Abstract

The elevation gain is an important contributor to the total workload in endurance sports. The purpose of this study was to evaluate the influence of the arm swing on elevation gain in three sport watches (Garmin® Forerunner 910XT, Polar® RS800CX and Suunto® Ambit2) on a flat 400 m outdoor track. Altogether, a total of 120 repetitions of 1,200 m were performed at self-selected speeds corresponding to strolling, walking, jogging and running. During the assessment two devices of each sport watch, one secured on the hip and one on the wrist, were worn by the participants. A small but significant (effect size = .39; p < .001) influence of the arm swing on elevation was revealed in all sport watches. Elevation indication errors recorded on the wrist were significantly larger than the ones recorded on the hip (4.0-7.4 vs. 1.2-5.7 m per 1,200 m; p < .05). Furthermore, when wearing the devices on the wrist, errors in elevation indication increased when gait speed increased. Users should be aware that wearing the devices on the hip can significantly decrease measurement errors. This might be especially relevant for activities with high dynamics, such as jogging and running.

Key words

  • workload
  • change in altitude
  • running
Open Access

Triathlon wetsuit removal strategy: physiological cost of running with a wetsuit

Published Online: 02 Jul 2016
Page range: 45 - 51

Abstract

Abstract

Triathletes exiting the swim portion of an event have to decide on how and when to take a wetsuit off (if worn). The purpose of this study was to determine the physiological cost of running while not using a wetsuit, carrying a wetsuit, wearing a wetsuit halfway down or wearing a wetsuit fully up. Participants (n = 20, 30.9 ± 8.7 yrs, 1.71 ± 0.08 m, 71.6 ± 9.5 kg) completed four 5 min running conditions: 1) not wearing the wetsuit, 2) wearing the wetsuit fully up, 3) wearing the wetsuit halfway down, and 4) carrying the wetsuit. A rate of oxygen uptake, a heart rate, ratings of perceived exertion and stride frequency were measured and were each influenced by wetsuit condition (p < 0.05). Each variable (i.e., a rate of oxygen uptake, a heart rate, stride frequency) was lower during running while not wearing the wetsuit vs. any other condition (p < 0.05). The rate of oxygen uptake was greatest during wearing the wetsuit halfway down vs. any other condition (p < 0.05). The heart rate was not different between any of the combinations of either wearing the wetsuit fully up or halfway down or carrying the wetsuit (p > 0.05). The rating of perceived exertion was greater during wearing the wetsuit halfway down vs. carrying the wetsuit (p < 0.05). Stride frequency was lower during not wearing the wetsuit vs. wearing the wetsuit halfway down or fully up (p < 0.05). It was concluded that running with the wetsuit halfway down resulted in the greatest rate of oxygen uptake, heart rate and rating of perceived exertion.

Key words

  • running economy
  • fatigue
  • race performance
Open Access

Relationships between movements of the lower limb joints and the pelvis in open and closed kinematic chains during a gait cycle

Published Online: 02 Jul 2016
Page range: 37 - 43

Abstract

Abstract

Lots of athletic skills performed during practice or competition are initiated by the legs, where athletes either walk or run prior to executing specific skills. Kinematic chains are used to describe the relationships between body segments and joints during movement. The aim of this study was to determine the relationships between movements of lower limb segments and the pelvis in open and closed kinematic chains while walking. The experimental group consisted of 32 males (age 23.3 ± 2.5 years, body mass 78.1 ± 8.7 kg, body height 182 ± 6 cm). For 3D analysis, an optoelectronic system Vicon MX (7 cameras, frequency 200 Hz) was used. Positioning of the segments was determined by the PlugInGait Model. Each participant executed five trials at speeds ranging from 1.38 to 1.52 m·s-1. The relationships between angle variables of the lower limbs and the pelvis in selected gait cycle phases were evaluated using STATISTICA software (version 10.0) and the Spearman correlation. The highest numbers of moderate and large correlations were found at opposite toe off, heel rise and initial contact for the sagittal and transversal planes in comparison to the frontal plane. The closed kinematic chain had a stronger impact on determining the movement pattern. The instructions or interventions focusing on closed kinematic chain alternation are more effective for changes in a movement pattern. The preferred limb initiates kinematics in the direction of propulsion, while the non-preferred limb in internal and external rotation.

Key words

  • walking
  • coupling
  • intra-limb
  • coordination
Open Access

The effect of exercise intensity on cognitive performance during short duration treadmill running

Published Online: 02 Jul 2016
Page range: 27 - 35

Abstract

Abstract

This study examined the effect of short duration, moderate and high-intensity exercise on a Go/NoGo task. Fifteen, habitually active (9 females and 6 males aged 28 ± 5 years) agreed to participate in the study and cognitive performance was measured in three sessions lasting 10 min each, performed at three different exercise intensities: rest, moderate and high. Results indicated significant exercise intensity main effects for reaction time (RT) (p = 0.01), the omission error rate (p = 0.027) and the decision error rate (p = 0.011), with significantly longer RTs during high intensity exercise compared to moderate intensity exercise (p = 0.039) and rest (p = 0.023). Mean ± SE of RT (ms) was 395.8 ± 9.1, 396.3 ± 9.1 and 433.5 ± 16.1 for rest, moderate and high intensity exercise, respectively. This pattern was replicated for the error rate with a significantly higher omission error and decision error rate during high intensity exercise compared to moderate intensity exercise (p = 0.003) and rest (p = 0.001). Mean ± SE of omission errors (%) was 0.88 ± 0.23, 0.8 ± 0.23 and 1.8 ± 0.46% for rest, moderate and high intensity exercise, respectively. Likewise, mean ± SE of decision errors (%) was 0.73 ± 0.24, 0.73 ± 0.21 and 1.8 ± 0.31 for rest, moderate and high intensity exercise, respectively. The present study’s results suggest that 10 min workout at high intensity impairs RT performances in habitually active adults compared to rest or moderate intensity exercise.

Key words

  • Go/No-go task
  • Reaction Time
  • Response Inhibition
Open Access

Evaluating injury risk in first and second league professional Portuguese soccer: muscular strength and asymmetry

Published Online: 02 Jul 2016
Page range: 19 - 26

Abstract

Abstract

Strength imbalances between the hamstrings and quadriceps are an essential predictor for hamstring strain in soccer. The study aimed to investigate and compare the muscle strength imbalances of professional soccer players of different performance levels. One hundred and fifty nine senior male professional soccer players from first (n = 75) and second league (n = 84) Portuguese clubs participated in this study. Muscle strength was evaluated with a REV9000 isokinetic dynamometer. Maximal peak torque data were used to calculate quadriceps and hamstrings strength during concentric and eccentric actions, bilateral asymmetry, conventional strength ratios and dynamic control ratios. Second league athletes produced slightly lower conventional strength ratios in the right and left legs (ES = 0.22, p = 0.17 and ES = 0.36, p = 0.023, respectively) compared to the first league athletes. No significant differences were found in dynamic control ratios or in bilateral asymmetry among first and second league athletes. These findings do not show a clear link between the competitive level and injury risk in soccer players. However, some of the differences found, particularly in conventional strength ratios, highlight the importance of performing off-season and pre-season strength assessments to prescribe and adjust individual strength training programs among professional soccer players.

Key words

  • dynamometry
  • isokinetic strength
  • H:Q ratios
  • muscle imbalances
Open Access

Chunk concatenation evolves with practice and sleep-related enhancement consolidation in a complex arm movement sequence

Published Online: 02 Jul 2016
Page range: 5 - 17

Abstract

Abstract

This paper addresses the notion of chunk concatenation being associated with sleep-related enhancement consolidation of motor sequence memory, thereby essentially contributing to improvements in sequence execution speed. To this end, element movement times of a multi-joint arm movement sequence incorporated in a recent study by Malangré et al. (2014) were reanalyzed. As sequence elements differed with respect to movement distance, element movement times had to be purged from differences solely due to varying trajectory lengths. This was done by dividing each element movement time per subject and trial block by the respective “reference movement time” collected from subjects who had extensively practiced each sequence element in isolation. Any differences in these “relative element movement times” were supposed to reflect element-specific “production costs” imposed solely by the sequence context. Across all subjects non-idiosyncratic, lasting sequence segmentation was shown, and four possible concatenation points (i.e. transition points between successive chunks) within the original arm movement sequence were identified. Based on theoretical suppositions derived from previous work with the discrete sequence production task and the dual processor model (Abrahamse et al., 2013), significantly larger improvements in transition speed occurring at these four concatenation points as compared to the five fastest transition positions within the sequence (associated with mere element execution) were assumed to indicate increased chunk concatenation. As a result, chunk concatenation was shown to proceed during acquisition with physical practice, and, most importantly, to significantly progress some more during retention following a night of sleep, but not during a waking interval.

Key words

  • motor sequence learning
  • memory consolidation
  • offline learning
  • sleep
  • gross motor skill

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