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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 57 (2017): Issue 1 (June 2017)

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

Search

24 Articles

Letter to the Editor

Section I – Kinesiology

Open Access

The Effects of Bench Press Variations in Competitive Athletes on Muscle Activity and Performance

Published Online: 22 Jun 2017
Page range: 61 - 71

Abstract

Abstract

The aim of the study was to compare the EMG activity performing 6RM competition style bench press (flat bench-wide grip) with 1) medium and narrow grip widths on a flat bench and 1) inclined and declined bench positions with a wide grip. Twelve bench press athletes competing at national and international level participated in the study. EMG activity was measured in the pectoralis major, anterior and posterior deltoid, biceps brachii, triceps brachii and latissimus dorsi. Non-significant differences in activation were observed between the three bench positions with the exception of 58.5-62.6% lower triceps brachii activation, but 48.3-68.7% greater biceps brachii activation in the inclined bench compared with the flat and declined bench position. Comparing the three grip widths, non-significant differences in activations were observed, with the exception of 25.9-30.5% lower EMG activity in the biceps brachii using a narrow grip, compared to the medium and wide grip conditions. The 6-RM loads were 5.8-11.1% greater using a medium and wide grip compared to narrow grip width and 18.5-21.5% lower in the inclined bench position compared with flat and declined. Comparing the EMG activity during the competition bench press style with either the inclined and declined bench position (wide grip) or using a narrow and medium grip (flat bench), only resulted in different EMG activity in the biceps- and triceps brachii. The 6RM loads varied with each bench press variation and we recommend the use of a wide grip on a flat bench during high load hypertrophy training to bench press athletes.

Key words

  • Resistance
  • training
  • strength
  • performance
Open Access

Trunk Strength Characteristics of Elite Alpine Skiers - A Comparison with Physically Active Controls

Published Online: 22 Jun 2017
Page range: 51 - 59

Abstract

Abstract

Core muscle imbalances and weak trunk strength are relevant for injury prevention and performance. Information regarding core strength requirements and ideal flexion/extension ratios in alpine skiing is limited. We aimed to compare trunk strength capacities in elite alpine skiers with those of a matched control group. The concentric maximal trunk flexion and extension of 109 elite skiers and 47 active controls were measured at 150°/s in a ballistic mode using the CON-TREX® TP 1000 test system. The relative flexion peak torque was higher in male ski racers (p = 0.003; 2.44 ± 0.30 Nm/kg) than in the controls (2.32 ± 0.42 Nm/kg). The relative peak torque for extension was 4.53 ± 0.65 Nm/kg in ski racers and 4.11 ± 0.52 Nm/kg in the controls (p = 0.001). Female athletes were significantly stronger in both, relative flexion force (p = 0.006; skiers 2.05 ± 0.22 Nm/kg; controls 1.74 ± 0.28 Nm/kg) and relative extension force (p = 0.001; skiers 3.55 ± 0.53 Nm/kg; controls 3.14 ± 0.48 Nm/kg). No significant differences were found in the ratios of flexion to extension forces in females and males. Ski racers are engaged in extensive strength training for both leg and trunk muscles, which explains the higher peak values. Both groups indicated a low ratio from 0.54-0.59, which represents high trunk extensor muscles strength relative to flexor muscles.

Key words

  • alpine skiing
  • elite athletes
  • core strength
  • flexion/extension core ratio
Open Access

Personal and Social Responsibility Among Athletes: the Role of Self-Determination, Achievement Goals and Engagement

Published Online: 22 Jun 2017
Page range: 39 - 50

Abstract

Abstract

The purpose of this study was to assess the relationship between motivation, engagement and personal and social responsibility among athletes. Based on the literature, a survey was conducted including measures of motivation, considering task orientation and ego orientation, intrinsic and extrinsic motivation, and amotivation. We also measured the components of engagement (dedication, confidence, vigor and enthusiasm) and the components of personal and social responsibility. A total of 517 athletes from different types of sports participated in the study. The results gathered through a structural equation model revealed that task orientation had the strongest relationship with personal responsibility and social responsibility, followed by engagement. Self-determination levels were not associated with personal and social responsibility. These results suggest that monitoring of task orientation and engagement levels should be performed by coaches as a strategy to develop personal and social responsibility among their athletes. Moreover, findings from this study provide scholars with a tool to aid them in managing athletes’ levels of personal and social responsibility.

Key words

  • psychology
  • sport
  • athletes
  • motivation
Open Access

Post Activation Potentiation of the Plantarflexors: Implications of Knee Angle Variations

Published Online: 22 Jun 2017
Page range: 29 - 38

Abstract

Abstract

Flexing the knee to isolate the single joint soleus from the biarticular gastrocnemius is a strategy for investigating individual plantarflexor’s post activation potentiation (PAP). We investigated the implications of testing plantarflexor PAP at different knee angles and provided indirect quantification of the contribution of gastrocnemius potentiation to the overall plantarflexor enhancements post conditioning. Plantarflexor supramaximal twitches were measured in ten male power athletes before and after a maximal isometric plantarflexion (MVIC) at both flexed and extended knee angles. Mean torque and soleus (SOLRMS) and medial gastrocnemius (MGRMS) activity were measured during the MVIC. The mean torque and MGRMS of the MVIC were lower (by 33.9 and 42.4%, respectively) in the flexed compared to the extended position, with no significant difference in SOLRMS. After the MVIC, twitch peak torque (PT) and the rate of torque development (RTR) potentiated significantly more (by 17.4 and 14.7% respectively) in the extended as compared to the flexed knee position, but only immediately (5 s) after the MVIC. No significant differences were found in the twitch rate of torque development (RTD) potentiation between positions. It was concluded that knee joint configuration should be taken into consideration when comparing studies of plantarflexor PAP. Furthermore, results reflect a rather brief contribution of the gastrocnemius potentiation to the overall plantarflexor twitch enhancements.

Key words

  • potentiation
  • twitch
  • electrical stimulation
  • triceps surae
  • knee angle
  • acute effects
Open Access

A Pilot Study of the Effect of Outsole Hardness on Lower Limb Kinematics and Kinetics during Soccer Related Movements

Published Online: 22 Jun 2017
Page range: 17 - 27

Abstract

Abstract

The purpose of this study was to investigate the effect of different outsole hardness of turf cleats shoes on the lower limb kinematics and kinetics of soccer players playing on artificial turf. The participants were required to complete tasks of straight running and 45° left sidestep cutting movements, respectively, at the speed of 4.5 ± 0.2 m/s on artificial turf. They were asked to randomly select turf cleats shoes with a soft outsole (SO), medium hardness outsole (MO) and hard outsole (HO). During the stance phase of straight running, peak pressure and force-time integral in medial forefoot (MFF) of players wearing cleats shoes with MO were significantly higher than those wearing cleats shoes with SO. During the stance phase of a 45° cutting maneuver, players wearing cleats shoes with SO showed significantly higher peak knee flexion and abduction angles than the HO group. Players wearing cleats shoes with SO also showed higher ankle dorsiflexion and inversion angles compared with those wearing cleats shoes with HO. The vertical average loading rate (VALR) as well as peak pressure and force-time integral in the heel (H) and lateral forefoot (LFF) regions of players wearing cleats shoes with HO were significantly higher than those wearing shoes with SO. On the contrary, peak pressure and force-time integral of players wearing shoes with SO were significantly higher than those wearing shoes with HO in MFF. A higher vertical loading rate and plantar pressure of some areas may increase the potential risk of metatarsal stress fractures and plantar fasciitis. Therefore, this finding about turf cleats shoes could give some theoretic support for the design of turf cleats shoes and material optimization in the future.

Key words

  • turf cleats shoes
  • outsole hardness
  • performance
  • injury
Open Access

Balance, Basic Anthropometrics and Performance in Young Alpine Skiers; Longitudinal Analysis of the Associations During Two Competitive Seasons

Published Online: 22 Jun 2017
Page range: 7 - 16

Abstract

Abstract

Balance is hypothesized to be important in alpine skiing, while it is known that balance depends on anthropometric indices. The aim of this investigation was to explore the association between balance, anthropometrics and skiing-results over two competitive seasons among youth alpine-skiers. Eighty-one skiers (40 females) participated in this study. The participants were tested twice over two competitive seasons: when they were 12-13 years old (U14) and when they were 14-15 years old (U16). The variables consisted of anthropometrics (body height and body mass) and three balance indexes (medio-lateral-, anterio-posterior- and overall-stability-index). Additionally, skiing results in U14 and U16 were evaluated. The balance status did not change significantly over the observed period of time regardless of the significant changes in body mass and height. The relationships between balance and skiing results were higher in the U14 (Pearson’s r = 0.45-0.54) than in the U16 (Pearson’s r = 0.05-0.28). The relationships between anthropometrics and competitive results were generally stronger in girls (Pearson’s r = 0.39-0.88) than in boys (Pearson’s r = 0.26-0.58). After clustering athletes into three achievement groups on a basis of their competitive performance, discriminant canonical analysis showed that relationships between balance and skiing results decreased, while the relationships between anthropometrics and skiing results increased over the two observed seasons. This study highlighted the importance of balance in youth alpine skiing in the age range of 11-14 years.

Key words

  • coaching
  • testing
  • biomechanics
  • physical performance

Section II- Exercise Physiology & Sports Medicine

Open Access

Cardiopulmonary Performance During Maximal Exercise in Soccer Players with Alterations in Renal Function

Published Online: 22 Jun 2017
Page range: 107 - 115

Abstract

Abstract

The aim of this study was to evaluate the curves of cardiorespiratory variables during cardiopulmonary exercise testing (CPET) in soccer players who had acute alterations in the glomerular filtration rate (GFR) after performing the pre-season training protocol. Sixteen male professional soccer players (25 ± 3 years; 179 ± 2 cm; and 77 ± 6 kg) were evaluated for oxygen uptake (VO2), heart rate (HR) and pulse relative oxygen (relative O2 Pulse) curves with intervals corresponding to 10% of the total duration of CPET. Athletes were grouped according to the GFR and classified as decreased GFR (dGFR; n = 8) and normal GFR (nGFR; n = 8). Athletes from the dGFR group exhibited lower VO2 values (p < 0.05) when 90% (dGFR 49.8 ± 4.0 vs. nGFR 54.4 ± 6.1 ml·kg-1·min-1) and 100% (dGFR 52.6 ± 4.1 vs. nGFR 57.4 ± 5.9 ml·kg-1·min-1) of the test was complete; HR high values (p < 0.05) when 90% (dGFR 183.7 ± 5.1 vs. nGFR 176.6 ± 4.8 bpm-1) and 100% (dGFR 188.1 ± 5.0 vs. nGFR 180.8 ± 4.8 bpm-1) of the test was complete; and lower relative O2 Pulse values (p < 0.05) when 70% (dGFR 25.6 ± 8.4 vs. nGFR 27.9 ± 9.7 ml·beat-1·kg-1), 80% (dGFR 26.6 ± 8.8 vs. nGFR 29.1 ± 10.0 ml·beat-1·kg-1), 90% (dGFR 27.1 ± 9.0 vs. nGFR 30.8 ± 10.6 ml·beat-1·kg-1) and 100% (dGFR 28 ± 9.2 vs. nGFR 31.8 ± 10.9 ml·beat-1·kg-1) of the test was complete. A correlation was found (r = −0.66, R2 = 0.44, p = 0.00) between lower VO2 peak and elevated levels of urinary protein excretion. In conclusion, soccer players with reduced kidney function after performing the pre-season training protocol also presented alterations in cardiopulmonary variables. We suggest that monitoring of renal function may be used to identify less conditioned soccer players.

Key words

  • kidney
  • glomerular filtration rate
  • athletes
  • exercise test
  • treadmill
Open Access

The Effect of Foam Rolling on Recovery Between Two Eight Hundred Metre Runs

Published Online: 22 Jun 2017
Page range: 97 - 105

Abstract

Abstract

With the increased popularity of foam rolling as a means of recovery, it is important to establish the exact manner in which the practice is useful. The purpose of this study was to examine the impact of foam rolling on recovery between two 800 m runs. Sixteen trained males (mean ± sd; age, 20.5 ± .5 yr; average 800 m treadmill run time, 145.2 ± 1.8 s) participated in the study, using a randomized, crossover design. The subjects completed two 800 m runs on a treadmill, separated by a 30 min rest, during which time a foam rolling protocol or passive rest period was performed. The speed of each run was as fast as possible. Subjects had access to speed controls, but were blinded to the actual speed. Blood lactate concentration and V. $\it V^{.}$ CO2 were measured prior to and following each run. Stride length, 800 m run time, and hip extension were measured during each run. V. $\it V^{.}$ CO2, stride length, 800 m run time, and hip extension were not significantly different between conditions (p > .05). For blood lactate, no statistical interaction was found between condition and time (p > .05). Foam rolling between two 800 m runs separated by 30 min performed by trained male runners does not alter performance.

Key words

  • lactate
  • range of motion
  • foam rolling
Open Access

The Effects of Maximal Intensity Exercise on Cognitive Performance in Children

Published Online: 22 Jun 2017
Page range: 85 - 96

Abstract

Abstract

High intensity physical exercise has previously been found to lead to a decline in cognitive performance of adults. The aim of this study was to determine the effects of maximal intensity exercise on cognitive performance of children. Using a repeated-measures design, 20 children and adolescents aged 8-17 years completed a battery of tests measuring memory and attention. Forward and Backward Digit Span tests, the Rey Auditory-Verbal Learning Test (RAVLT) and the Digit Symbol Substitution Test (DSST) were performed at baseline, immediately after, and one hour after a maximal cardiopulmonary exercise test. Forward and Backward Digit Span scores significantly improved post-recovery compared with baseline measurements. There was a significant decrease in RAVLT scores post-exercise, which returned to baseline values after recovery. The DSST test scores were mildly elevated from post-exercise to after recovery. Maximal intensity exercise in children and adolescents may result in both beneficial and detrimental cognitive effects, including transient impairment in verbal learning. Cognitive functions applying short term memory improve following a recovery period. Parents, educators and coaches should consider these changes in memory and attention following high-intensity exercise activities in children.

Key words

  • neurocognitive
  • verbal learning
  • physical activity
  • short term memory
  • cognition
  • pediatrics
Open Access

Effects of an Elastic Hamstring Assistance Device During Downhill Running

Published Online: 22 Jun 2017
Page range: 73 - 83

Abstract

Abstract

The purpose of this study was to determine the appropriateness of using an elastic hamstring assistance device to reduce perceived levels of soreness, increase isometric strength, increase passive range of motion, and decrease biomarkers of muscle damage after eccentric exercise, specifically, downhill running This study was conducted in a university exercise physiology laboratory placing sixteen apparently healthy males (X = 21.6 ± 2.5 years) into two groups using a pre-test/post-test design. Pre-intervention measures taken included participants’ body height, body mass, body fat, capillary blood samples, VO2max, isometric hamstring strength at 45 and 90 degrees of flexion and passive hamstring range of motion. Post-intervention measures included blood biomarkers, passive range of motion, the perceived level of soreness and isometric strength. An analysis of normality of data was initially conducted followed by multivariate analysis of variance (MANOVA) of hamstring strength at 45 and 90 degrees of flexion, blood myoglobin and passive range of motion of the hamstrings. Statistically significant changes were noted in subject-perceived muscle soreness and isometric strength at 90 degrees at the 24-hour post-exercise trial measure between the two groups. Results would suggest the findings could be explained by the decrease in muscle soreness from utilizing the device during the exercise trial. Further research should be conducted to address sample size issues and to determine if the results are comparable on different surfaces.

Key words

  • soreness
  • isometrics
  • hamstring
  • myoglobin

Section III – Sports Training

Open Access

Performance Trends in Master Butterfly Swimmers Competing in the FINA World Championships

Published Online: 22 Jun 2017
Page range: 199 - 211

Abstract

Abstract

Performance trends in elite butterfly swimmers are well known, but less information is available regarding master butterfly swimmers. We investigated trends in participation, performance and sex differences in 9,606 female and 13,250 male butterfly race times classified into five-year master groups, from 25-29 to 90-94 years, competing in the FINA World Masters Championships between 1986 and 2014. Trends in participation were analyzed using linear regression analysis. Trends in performance changes were investigated using mixed-effects regression analyses with sex, distance and a calendar year as fixed variables. We also considered interaction effects between sex and distance. Participation increased in master swimmers older than ~30-40 years. The men-to-women ratio remained unchanged across calendar years and master groups, but was lower in 200 m compared to 50 m and 100 m. Men were faster than women from 25-29 to 85-89 years (p < 0.05), although not for 90-94 years. Sex and distance showed a significant interaction in all master groups from 25-29 to 90-94 years for 200m (p < 0.05). For 50 m and 100 m, a significant sex × distance interaction was observed from 25-29 to 75-79 years (p < 0.05), but not in the older groups. In 50 m, women reduced the sex difference in master groups 30-34 to 60-64 years (p < 0.05). In 100 m, women decreased the gap to men in master groups 35-39 to 55-59 years (p < 0.05). In 200 m, the sex difference was reduced in master groups 30-34 to 40-44 years (p < 0.05). In summary, women and men improved performance at all distances, women were not slower compared to men in the master group 90-94 years; moreover, women reduced the gap to men between ~30 and ~60 years, although not in younger or older master groups.

Key words

  • aging
  • master athletes
  • sex difference
  • swimming
Open Access

Assessment of Specificity of the Badcamp Agility Test for Badminton Players

Published Online: 22 Jun 2017
Page range: 191 - 198

Abstract

Abstract

The Badcamp agility test was created to evaluate agility of badminton players. The Badcamp is a valid and reliable test, however, a doubt about the need for the use of this test exists as simpler tests could provide similar information about agility in badminton players. Thus, the aim of this study was to examine the specificity of the Badcamp, comparing the performance of badminton players and athletes from other sports in the Badcamp and the shuttle run agility test (SRAT). Sixty-four young male and female athletes aged between 14 and 16 years participated in the study. They were divided into 4 groups of 16 according to their sport practices: badminton, tennis, team sport (basketball and volleyball), and track and field. We compared the groups in both tests, the Badcamp and SRAT. The results revealed that the group of badminton players was faster compared to all other groups in the Badcamp. However, in the SRAT there were no differences among groups composed of athletes from open skill sports (e.g., badminton, tennis, and team sports), and a considerable reduction of the difference between badminton players and track and field athletes. Thus, we concluded that the Badcamp test is a specific agility test for badminton players and should be considered in evaluating athletes of this sport modality.

Key words

  • badminton
  • racket
  • sport
  • quickness
  • uncertainty
  • reaction time
Open Access

Differences in Anthropometry, Biological Age and Physical Fitness Between Young Elite Kayakers and Canoeists

Published Online: 22 Jun 2017
Page range: 181 - 190

Abstract

Abstract

The aim of this study was to determine the anthropometric and physical characteristics of youth elite paddlers and to identify the differences between kayakers and canoeists. A total of 171 male paddlers (eighty-nine kayakers and eighty-two canoeists), aged 13.69 ± 0.57 years (mean ± SD) volunteered to participate in this study. The participants completed basic anthropometric assessments (body mass, stretch stature, sitting height, body mass index, maturity level, sum of 6 skinfolds and fat mass percentage) as well as a battery of physical fitness tests (overhead medicine ball throw, counter movement jump, sit-and-reach and 20 m multi-stage shuttle run tests). The anthropometric results revealed a significantly larger body size (stretch stature and sitting height) and body mass in the kayakers (p < 0.01) as well as a more mature biological status (p = 0.003). The physical fitness level exhibited by the kayakers was likewise significantly greater than that of the canoeists, both in the counter movement jump and estimated VO2max (p < 0.05), as well as in the overhead medicine ball throw and sit-and-reach test (p < 0.01). These findings confirm the more robust and mature profile of youth kayakers that might be associated with the superior fitness level observed and the specific requirements of this sport discipline.

Key words

  • anthropometry
  • physical fitness
  • biological age
  • kayak
  • canoe
Open Access

Anthropometric Profile in Different Event Categories of Acrobatic Gymnastics

Published Online: 22 Jun 2017
Page range: 169 - 179

Abstract

Abstract

There is a specific anthropometric profile for each sport, which may be differentiated even in relation to the position, role or event category within each sport discipline. However, there are few studies on acrobatic gymnastics, and the goal of this work was to determine the anthropometric profile depending on the event category, as well as factors that predisposed to performance in these categories. The sample consisted of 150 gymnasts from Spain, divided into 8 groups according to the event category and the role played. The kinanthropometric measurements were taken through the procedures established by the International Society for the Advancement of Kineantropometry. The anthropometric characteristics, including body mass index, somatotype, body composition and proportionality using the Phantom stratagem were analyzed, and the results obtained from the different groups were compared. A regression analysis was performed with particular groups of gymnasts. No significant differences (p < 0.05) were observed between groups of female tops or male bases, although differences were found between female group bases and female pair bases. It could be suggested that higher values of body height, sitting height, the minimum abdominal circumference, percentage of fat and low biliocristal breadth predispose female bases to work in pairs rather than in groups. The conclusion is that the anthropometric measurements are not decisive when guiding a gymnast toward choosing one event category or another, except for female bases.

Key words

  • morphological characteristics
  • phantom stratagem for proportionality assessment
  • body mass index
  • somatotype and body composition
Open Access

A Model for Determining the Effect of the Wind Velocity on 100 M Sprinting Performance

Published Online: 22 Jun 2017
Page range: 159 - 167

Abstract

Abstract

This paper introduces an equation for determining instantaneous and final velocity of a sprinter in a 100 m run completed with a wind resistance ranging from 0.1 to 4.5 m/s. The validity of the equation was verified using the data of three world class sprinters: Carl Lewis, Maurice Green, and Usain Bolt. For the given constant wind velocity with the values + 0.9 and + 1.1 m/s, the wind contribution to the change of sprinter velocity was the same for the maximum as well as for the final velocity. This study assessed how the effect of the wind velocity influenced the change of sprinting velocity. The analysis led to the conclusion that the official limit of safely neglecting the wind influence could be chosen as 1 m/s instead of 2 m/s, if the velocity were presented using three, instead of two decimal digits. This implies that wind velocity should be rounded off to two decimal places instead of the present practice of one decimal place. In particular, the results indicated that the influence of wind on the change of sprinting velocity in the range of up to 2 m/s and was of order of magnitude of 10-3 m/s. This proves that the IAAF Competition Rules correctly neglect the influence of the wind with regard to such velocities. However, for the wind velocity over 2 m/s, the wind influence is of order 10-2 m/s and cannot be neglected.

Key words

  • mathematical modelling
  • track sprinting
  • wind
Open Access

Quality Versus Quantity Debate in Swimming: Perceptions and Training Practices of Expert Swimming Coaches

Published Online: 22 Jun 2017
Page range: 147 - 158

Abstract

Abstract

The debate over low-volume, high-intensity training versus high-volume, low-intensity training, commonly known as Quality versus Quantity, respectively, is a frequent topic of discussion among swimming coaches and academics. The aim of this study was to explore expert coaches’ perceptions of quality and quantity coaching philosophies in competitive swimming and to investigate their current training practices. A purposeful sample of 11 expert swimming coaches was recruited for this study. The study was a mixed methods design and involved each coach participating in 1 semi-structured interview and completing 1 closed-ended questionnaire. The main findings of this study were that coaches felt quality training programmes would lead to short term results for youth swimmers, but were in many cases more appropriate for senior swimmers. The coaches suggested that quantity training programmes built an aerobic base for youth swimmers, promoted technical development through a focus on slower swimming and helped to enhance recovery from training or competition. However, the coaches continuously suggested that quantity training programmes must be performed with good technique and they felt this was a misunderstood element. This study was a critical step towards gaining a richer and broader understanding on the debate over Quality versus Quantity training from an expert swimming coaches’ perspective which was not currently available in the research literature.

Key words

  • high-intensity training
  • high-volume training
  • long term athlete development
  • coaching philosophy
  • mixed methods
Open Access

Intra-Subject Variability of 5 Km Time Trial Performance Completed by Competitive Trained Runners

Published Online: 22 Jun 2017
Page range: 139 - 146

Abstract

Abstract

Time-trials represent an ecologically valid approach to assessment of endurance performance. Such information is useful in the application of testing protocols and estimation of sample sizes required for research/magnitude based inference methods. The present study aimed to investigate the intra-subject variability of 5 km time-trial running performance in trained runners. Six competitive trained male runners (age = 33.8 ± 10.1 years; stature = 1.78 ± 0.01 m; body mass = 69.0 ± 10.4 kg, V. $\it V^{.}$ O2max = 62.6 ± 11.0 ml·kg·min-1) completed an incremental exercise test to volitional exhaustion followed by 5 x 5 km time-trials (including a familiarisation trial), individually spaced by 48 hours. The time taken to complete each trial, heart rate, rating of perceived exertion and speed were all assessed. Intra-subject absolute standard error of measurement and the coefficient of variance were calculated for time-trial variables in addition to the intra-class correlation coefficient for time taken to complete the time-trial. For the primary measure time, results showed a coefficient of variation score across all participants of 1.5 ± 0.59% with an intra-class correlation coefficient score of 0.990. Heart rate, rating of perceived exertion and speed data showed a variance range between 0.8 and 3.05%. It was concluded that when compared with related research, there was observed low intra-subject variability in trained runners over a 5 km distance. This supports the use of this protocol for 5 km time-trial performance for assessment of nutritional strategies, ergogenic aids or training interventions on endurance running performance.

Key words

  • endurance
  • running economy
  • reliability
Open Access

A Comparison of GPS Workload Demands in Match Play and Small-Sided Games by the Positional Role in Youth Soccer

Published Online: 22 Jun 2017
Page range: 129 - 137

Abstract

Abstract

The external demands of small-sided games (SSGs) according to the positional role are currently unknown. Using a Catapult Minimax X3 5 Hz GPS, with a 100 Hz tri-axial accelerometer, we compared the accumulated tri-axial player workload per min (PLacc·min-1) during friendly youth match play (MP) (11 vs. 11) and SSGs (2 vs. 2, 3 vs. 3, and 4 vs. 4). Significant differences existed between all SSGs and MP for PLacc·min-1 (F = 21.91, p < 0.001, η2 = 0.38), and individual X (F = 27.40, p < 0.001, η2 = 0.43), Y (F = 14.50, p < 0.001, η2 = 0.29) and Z (F = 19.28, p < 0.001, η2 = 0.35) axis loads. Across all conditions, mean PLacc·min-1 was greater for midfielders (p = 0.004, CI: 0.68, 4.56) and forwards (p = 0.037, CI: 0.08, 3.97) than central defenders. In all conditions, greater Y axis values existed for wide defenders (p = 0.024, CI: 0.67, 1.38), midfielders (p = 0.006, CI: 0.18, 1.50) and forwards (p = 0.007, CI: 0.17, 0.15) compared to central defenders. Midfielders reported greater Z axis values compared to central defenders (p = 0.002, CI: 0.40, 2.23). We concluded that SSGs elicited greater external loads than MP, and previous studies may have underestimated the demands of SSGs.

Key words

  • small sided games
  • training games
  • conditioning
  • soccer
  • player load
  • GPS
Open Access

A Rapidly-Incremented Tethered-Swimming Test for Defining Domain-Specific Training Zones

Published Online: 22 Jun 2017
Page range: 117 - 128

Abstract

Abstract

The purpose of this study was to investigate whether a tethered-swimming incremental test comprising small increases in resistive force applied every 60 seconds could delineate the isocapnic region during rapidly-incremented exercise. Sixteen competitive swimmers (male, n = 11; female, n = 5) performed: (a) a test to determine highest force during 30 seconds of all-out tethered swimming (Favg) and the ΔF, which represented the difference between Favg and the force required to maintain body alignment (Fbase), and (b) an incremental test beginning with 60 seconds of tethered swimming against a load that exceeded Fbase by 30% of ΔF followed by increments of 5% of ΔF every 60 seconds. This incremental test was continued until the limit of tolerance with pulmonary gas exchange (rates of oxygen uptake and carbon dioxide production) and ventilatory (rate of minute ventilation) data collected breath by breath. These data were subsequently analyzed to determine whether two breakpoints defining the isocapnic region (i.e., gas exchange threshold and respiratory compensation point) were present. We also determined the peak rate of O2 uptake and exercise economy during the incremental test. The gas exchange threshold and respiratory compensation point were observed for each test such that the associated metabolic rates, which bound the heavy-intensity domain during constant-work-rate exercise, could be determined. Significant correlations (Spearman’s) were observed for exercise economy along with (a) peak rate of oxygen uptake (ρ = .562; p < 0.025), and (b) metabolic rate at gas exchange threshold (ρ = −.759; p < 0.005). A rapidly-incremented tethered-swimming test allows for determination of the metabolic rates that define zones for domain-specific constant-work-rate training.

Key words

  • isocapnic region
  • gas exchange threshold
  • respiratory compensation point
  • exercise economy
  • constant-work-rate exercise
  • heavy intensity

Section IV – Behavioural Sciences in Sport

Open Access

The Relationship Between Perceived Coaching Behaviours, Motivation and Self-Efficacy in Wrestlers

Published Online: 22 Jun 2017
Page range: 239 - 251

Abstract

Abstract

The current study aimed to determine the relationship between perceived coaching behaviours, motivation, self-efficacy and general self-efficacy of wrestlers who competed in the Super National Wrestling League. The sample consisted of 289 wrestlers. The Self-Efficacy Scale was used to measure self-efficacy perception, the Sports Motivation Scale to measure the motivation of the athletes, the Leadership Scale for Sport to determine perceived leadership behaviours, and the General Self-Efficacy Scale to determine the general self-efficacy perceptions of the athletes. For data analyses, SPSS 17.0 software was used. According to the results of the regression analyses performed with the enter method, it was found that perceived training and instruction behaviour along with perceived social support behaviour significantly explained self-efficacy (adjusted R2_ = .03), intrinsic motivation (adjusted R2 = .04) and amotivation (adjusted R2 = .05). Also, perceived training and instruction behaviour (β = .51), autocratic behaviour (β = -.17) and social support behaviour (β = -.27) significantly contributed to athletes’ general self-efficacy (adjusted R2 = .10). In light of these findings, it may be argued that perceived training and instruction behaviour may be beneficial for self-efficacy, general self-efficacy, intrinsic motivation, and amotivation. On the other hand, it could be stated that perceived autocratic behaviour may be detrimental for general self-efficacy of the athletes. As for social support behaviour, it may be suggested that it is negatively related to self-efficacy, general self-efficacy and intrinsic motivation. Lastly, a positive relationship was observed between perceived social support behaviour and amotivation in wrestlers. The results reveal the specific characteristics of wrestlers and suggest some implications for wrestling coaches.

Key words

  • leadership
  • self-efficacy
  • motivation
  • coaching behaviours
  • wrestling
Open Access

Perceived Hindrances Experienced by Sport Coaches in South Africa

Published Online: 22 Jun 2017
Page range: 233 - 238

Abstract

Abstract

The purpose of this study was to examine perceived hindrances encountered by sport coaches in the Gauteng Province of South Africa. A total of 224 sport coaches (122 males and 102 females) were purposively recruited to participate in this study. An exploratory factor analysis was used to assess the factor structure of the Perceived Hindrance Scale. The results of this study indicated the following as major hindrances encountered by sport coaches: “Lack of support systems for women players”, “Lack of support for women coaches from superiors”, “Low salary”, “Lack of opportunities for promotion”, “Difficulties with parents/spectators” and “Lack of job security”. Recommendations on strategies to overcome these perceived hindrances are discussed.

Key words

  • coaching
  • hindrances
  • occupation
Open Access

Plantar Pressure Differences Between Nordic Walking Techniques

Published Online: 22 Jun 2017
Page range: 221 - 231

Abstract

Abstract

High plantar pressure has been associated with increased risk of injury. The characteristics of each physical activity determine the load on the lower limbs. The influence of Nordic Walking (NW) technique on plantar pressure is still unknown. The aim of this study was to analyze the differences between plantar pressure during NW with the Diagonal technique (DT) versus Alpha technique (AT) and compare them with the pressure obtained during normal walking (W). The normality and sphericity of the plantar pressure data were checked before performing a two-way repeated measures ANOVA in order to find differences between speeds (preferred, fast) and the gait (NW, W) as within-subject factors. Then, a t-test for independent measures was used to identify the specific differences between NW techniques. The strength of the differences was calculated by means of the effect size (ES). The results demonstrated that during NW with AT at preferred speed the pressure was lower under the Calcaneus, Lateral Metatarsal and Toes compared to the DT group (p = 0.046, ES = 1.49; p = 0.015, ES = 1.44; p = 0.040, ES = 1.20, respectively). No differences were found at the fast speed (p > 0.05). Besides the increase in walking speed during NW (p < 0.01), both technique groups showed lower pressure during NW compared to W under the Hallux and Central Metatarsal heads (F = 58.321, p = 0.000, ES = 2.449; F = 41.917, p = 0.012, ES = 1.365, respectively). As a practical conclusion, the AT technique may be the most effective of the NW techniques at reducing plantar pressure while allowing NW practitioners to achieve the physiological benefits of NW.

Key words

  • poles
  • biomechanics
  • foot
  • loading
Open Access

Home Advantage in Judo: Analysis by the Combat Phase, Penalties and the Type of Attack

Published Online: 22 Jun 2017
Page range: 213 - 220

Abstract

Abstract

Previous studies indicate positive home advantage in judo; however, the factors that influence home advantage have yet to be fully explored. This study investigated the potential differences in technical-tactical variables between home and visiting athletes. A total of 1411 video recorded matches were analyzed (123 home, 1288 away) from 36 international judo competitions contested in 2011-12. The matches were analyzed by the following criteria: combat phases (approach, gripping, attack, defense, groundwork and pause), penalties (by the athlete or the opponent) and the types of attacks (with or without a score). Elite judo athletes competing in their home country attacked more frequently using trunk/leg couple techniques (p < 0.011) and scored more frequently with arm/leg couple techniques (p < 0.001), while visiting judo athletes received fewer scores from penalties (p < 0.001) and engaged in more frequent pauses during competition (p < 0.01). The results of this study provide an outline of technical-tactical differences that may contribute to home advantage in judo.

Key words

  • home advantage
  • martial arts
  • performance analysis
24 Articles

Letter to the Editor

Section I – Kinesiology

Open Access

The Effects of Bench Press Variations in Competitive Athletes on Muscle Activity and Performance

Published Online: 22 Jun 2017
Page range: 61 - 71

Abstract

Abstract

The aim of the study was to compare the EMG activity performing 6RM competition style bench press (flat bench-wide grip) with 1) medium and narrow grip widths on a flat bench and 1) inclined and declined bench positions with a wide grip. Twelve bench press athletes competing at national and international level participated in the study. EMG activity was measured in the pectoralis major, anterior and posterior deltoid, biceps brachii, triceps brachii and latissimus dorsi. Non-significant differences in activation were observed between the three bench positions with the exception of 58.5-62.6% lower triceps brachii activation, but 48.3-68.7% greater biceps brachii activation in the inclined bench compared with the flat and declined bench position. Comparing the three grip widths, non-significant differences in activations were observed, with the exception of 25.9-30.5% lower EMG activity in the biceps brachii using a narrow grip, compared to the medium and wide grip conditions. The 6-RM loads were 5.8-11.1% greater using a medium and wide grip compared to narrow grip width and 18.5-21.5% lower in the inclined bench position compared with flat and declined. Comparing the EMG activity during the competition bench press style with either the inclined and declined bench position (wide grip) or using a narrow and medium grip (flat bench), only resulted in different EMG activity in the biceps- and triceps brachii. The 6RM loads varied with each bench press variation and we recommend the use of a wide grip on a flat bench during high load hypertrophy training to bench press athletes.

Key words

  • Resistance
  • training
  • strength
  • performance
Open Access

Trunk Strength Characteristics of Elite Alpine Skiers - A Comparison with Physically Active Controls

Published Online: 22 Jun 2017
Page range: 51 - 59

Abstract

Abstract

Core muscle imbalances and weak trunk strength are relevant for injury prevention and performance. Information regarding core strength requirements and ideal flexion/extension ratios in alpine skiing is limited. We aimed to compare trunk strength capacities in elite alpine skiers with those of a matched control group. The concentric maximal trunk flexion and extension of 109 elite skiers and 47 active controls were measured at 150°/s in a ballistic mode using the CON-TREX® TP 1000 test system. The relative flexion peak torque was higher in male ski racers (p = 0.003; 2.44 ± 0.30 Nm/kg) than in the controls (2.32 ± 0.42 Nm/kg). The relative peak torque for extension was 4.53 ± 0.65 Nm/kg in ski racers and 4.11 ± 0.52 Nm/kg in the controls (p = 0.001). Female athletes were significantly stronger in both, relative flexion force (p = 0.006; skiers 2.05 ± 0.22 Nm/kg; controls 1.74 ± 0.28 Nm/kg) and relative extension force (p = 0.001; skiers 3.55 ± 0.53 Nm/kg; controls 3.14 ± 0.48 Nm/kg). No significant differences were found in the ratios of flexion to extension forces in females and males. Ski racers are engaged in extensive strength training for both leg and trunk muscles, which explains the higher peak values. Both groups indicated a low ratio from 0.54-0.59, which represents high trunk extensor muscles strength relative to flexor muscles.

Key words

  • alpine skiing
  • elite athletes
  • core strength
  • flexion/extension core ratio
Open Access

Personal and Social Responsibility Among Athletes: the Role of Self-Determination, Achievement Goals and Engagement

Published Online: 22 Jun 2017
Page range: 39 - 50

Abstract

Abstract

The purpose of this study was to assess the relationship between motivation, engagement and personal and social responsibility among athletes. Based on the literature, a survey was conducted including measures of motivation, considering task orientation and ego orientation, intrinsic and extrinsic motivation, and amotivation. We also measured the components of engagement (dedication, confidence, vigor and enthusiasm) and the components of personal and social responsibility. A total of 517 athletes from different types of sports participated in the study. The results gathered through a structural equation model revealed that task orientation had the strongest relationship with personal responsibility and social responsibility, followed by engagement. Self-determination levels were not associated with personal and social responsibility. These results suggest that monitoring of task orientation and engagement levels should be performed by coaches as a strategy to develop personal and social responsibility among their athletes. Moreover, findings from this study provide scholars with a tool to aid them in managing athletes’ levels of personal and social responsibility.

Key words

  • psychology
  • sport
  • athletes
  • motivation
Open Access

Post Activation Potentiation of the Plantarflexors: Implications of Knee Angle Variations

Published Online: 22 Jun 2017
Page range: 29 - 38

Abstract

Abstract

Flexing the knee to isolate the single joint soleus from the biarticular gastrocnemius is a strategy for investigating individual plantarflexor’s post activation potentiation (PAP). We investigated the implications of testing plantarflexor PAP at different knee angles and provided indirect quantification of the contribution of gastrocnemius potentiation to the overall plantarflexor enhancements post conditioning. Plantarflexor supramaximal twitches were measured in ten male power athletes before and after a maximal isometric plantarflexion (MVIC) at both flexed and extended knee angles. Mean torque and soleus (SOLRMS) and medial gastrocnemius (MGRMS) activity were measured during the MVIC. The mean torque and MGRMS of the MVIC were lower (by 33.9 and 42.4%, respectively) in the flexed compared to the extended position, with no significant difference in SOLRMS. After the MVIC, twitch peak torque (PT) and the rate of torque development (RTR) potentiated significantly more (by 17.4 and 14.7% respectively) in the extended as compared to the flexed knee position, but only immediately (5 s) after the MVIC. No significant differences were found in the twitch rate of torque development (RTD) potentiation between positions. It was concluded that knee joint configuration should be taken into consideration when comparing studies of plantarflexor PAP. Furthermore, results reflect a rather brief contribution of the gastrocnemius potentiation to the overall plantarflexor twitch enhancements.

Key words

  • potentiation
  • twitch
  • electrical stimulation
  • triceps surae
  • knee angle
  • acute effects
Open Access

A Pilot Study of the Effect of Outsole Hardness on Lower Limb Kinematics and Kinetics during Soccer Related Movements

Published Online: 22 Jun 2017
Page range: 17 - 27

Abstract

Abstract

The purpose of this study was to investigate the effect of different outsole hardness of turf cleats shoes on the lower limb kinematics and kinetics of soccer players playing on artificial turf. The participants were required to complete tasks of straight running and 45° left sidestep cutting movements, respectively, at the speed of 4.5 ± 0.2 m/s on artificial turf. They were asked to randomly select turf cleats shoes with a soft outsole (SO), medium hardness outsole (MO) and hard outsole (HO). During the stance phase of straight running, peak pressure and force-time integral in medial forefoot (MFF) of players wearing cleats shoes with MO were significantly higher than those wearing cleats shoes with SO. During the stance phase of a 45° cutting maneuver, players wearing cleats shoes with SO showed significantly higher peak knee flexion and abduction angles than the HO group. Players wearing cleats shoes with SO also showed higher ankle dorsiflexion and inversion angles compared with those wearing cleats shoes with HO. The vertical average loading rate (VALR) as well as peak pressure and force-time integral in the heel (H) and lateral forefoot (LFF) regions of players wearing cleats shoes with HO were significantly higher than those wearing shoes with SO. On the contrary, peak pressure and force-time integral of players wearing shoes with SO were significantly higher than those wearing shoes with HO in MFF. A higher vertical loading rate and plantar pressure of some areas may increase the potential risk of metatarsal stress fractures and plantar fasciitis. Therefore, this finding about turf cleats shoes could give some theoretic support for the design of turf cleats shoes and material optimization in the future.

Key words

  • turf cleats shoes
  • outsole hardness
  • performance
  • injury
Open Access

Balance, Basic Anthropometrics and Performance in Young Alpine Skiers; Longitudinal Analysis of the Associations During Two Competitive Seasons

Published Online: 22 Jun 2017
Page range: 7 - 16

Abstract

Abstract

Balance is hypothesized to be important in alpine skiing, while it is known that balance depends on anthropometric indices. The aim of this investigation was to explore the association between balance, anthropometrics and skiing-results over two competitive seasons among youth alpine-skiers. Eighty-one skiers (40 females) participated in this study. The participants were tested twice over two competitive seasons: when they were 12-13 years old (U14) and when they were 14-15 years old (U16). The variables consisted of anthropometrics (body height and body mass) and three balance indexes (medio-lateral-, anterio-posterior- and overall-stability-index). Additionally, skiing results in U14 and U16 were evaluated. The balance status did not change significantly over the observed period of time regardless of the significant changes in body mass and height. The relationships between balance and skiing results were higher in the U14 (Pearson’s r = 0.45-0.54) than in the U16 (Pearson’s r = 0.05-0.28). The relationships between anthropometrics and competitive results were generally stronger in girls (Pearson’s r = 0.39-0.88) than in boys (Pearson’s r = 0.26-0.58). After clustering athletes into three achievement groups on a basis of their competitive performance, discriminant canonical analysis showed that relationships between balance and skiing results decreased, while the relationships between anthropometrics and skiing results increased over the two observed seasons. This study highlighted the importance of balance in youth alpine skiing in the age range of 11-14 years.

Key words

  • coaching
  • testing
  • biomechanics
  • physical performance

Section II- Exercise Physiology & Sports Medicine

Open Access

Cardiopulmonary Performance During Maximal Exercise in Soccer Players with Alterations in Renal Function

Published Online: 22 Jun 2017
Page range: 107 - 115

Abstract

Abstract

The aim of this study was to evaluate the curves of cardiorespiratory variables during cardiopulmonary exercise testing (CPET) in soccer players who had acute alterations in the glomerular filtration rate (GFR) after performing the pre-season training protocol. Sixteen male professional soccer players (25 ± 3 years; 179 ± 2 cm; and 77 ± 6 kg) were evaluated for oxygen uptake (VO2), heart rate (HR) and pulse relative oxygen (relative O2 Pulse) curves with intervals corresponding to 10% of the total duration of CPET. Athletes were grouped according to the GFR and classified as decreased GFR (dGFR; n = 8) and normal GFR (nGFR; n = 8). Athletes from the dGFR group exhibited lower VO2 values (p < 0.05) when 90% (dGFR 49.8 ± 4.0 vs. nGFR 54.4 ± 6.1 ml·kg-1·min-1) and 100% (dGFR 52.6 ± 4.1 vs. nGFR 57.4 ± 5.9 ml·kg-1·min-1) of the test was complete; HR high values (p < 0.05) when 90% (dGFR 183.7 ± 5.1 vs. nGFR 176.6 ± 4.8 bpm-1) and 100% (dGFR 188.1 ± 5.0 vs. nGFR 180.8 ± 4.8 bpm-1) of the test was complete; and lower relative O2 Pulse values (p < 0.05) when 70% (dGFR 25.6 ± 8.4 vs. nGFR 27.9 ± 9.7 ml·beat-1·kg-1), 80% (dGFR 26.6 ± 8.8 vs. nGFR 29.1 ± 10.0 ml·beat-1·kg-1), 90% (dGFR 27.1 ± 9.0 vs. nGFR 30.8 ± 10.6 ml·beat-1·kg-1) and 100% (dGFR 28 ± 9.2 vs. nGFR 31.8 ± 10.9 ml·beat-1·kg-1) of the test was complete. A correlation was found (r = −0.66, R2 = 0.44, p = 0.00) between lower VO2 peak and elevated levels of urinary protein excretion. In conclusion, soccer players with reduced kidney function after performing the pre-season training protocol also presented alterations in cardiopulmonary variables. We suggest that monitoring of renal function may be used to identify less conditioned soccer players.

Key words

  • kidney
  • glomerular filtration rate
  • athletes
  • exercise test
  • treadmill
Open Access

The Effect of Foam Rolling on Recovery Between Two Eight Hundred Metre Runs

Published Online: 22 Jun 2017
Page range: 97 - 105

Abstract

Abstract

With the increased popularity of foam rolling as a means of recovery, it is important to establish the exact manner in which the practice is useful. The purpose of this study was to examine the impact of foam rolling on recovery between two 800 m runs. Sixteen trained males (mean ± sd; age, 20.5 ± .5 yr; average 800 m treadmill run time, 145.2 ± 1.8 s) participated in the study, using a randomized, crossover design. The subjects completed two 800 m runs on a treadmill, separated by a 30 min rest, during which time a foam rolling protocol or passive rest period was performed. The speed of each run was as fast as possible. Subjects had access to speed controls, but were blinded to the actual speed. Blood lactate concentration and V. $\it V^{.}$ CO2 were measured prior to and following each run. Stride length, 800 m run time, and hip extension were measured during each run. V. $\it V^{.}$ CO2, stride length, 800 m run time, and hip extension were not significantly different between conditions (p > .05). For blood lactate, no statistical interaction was found between condition and time (p > .05). Foam rolling between two 800 m runs separated by 30 min performed by trained male runners does not alter performance.

Key words

  • lactate
  • range of motion
  • foam rolling
Open Access

The Effects of Maximal Intensity Exercise on Cognitive Performance in Children

Published Online: 22 Jun 2017
Page range: 85 - 96

Abstract

Abstract

High intensity physical exercise has previously been found to lead to a decline in cognitive performance of adults. The aim of this study was to determine the effects of maximal intensity exercise on cognitive performance of children. Using a repeated-measures design, 20 children and adolescents aged 8-17 years completed a battery of tests measuring memory and attention. Forward and Backward Digit Span tests, the Rey Auditory-Verbal Learning Test (RAVLT) and the Digit Symbol Substitution Test (DSST) were performed at baseline, immediately after, and one hour after a maximal cardiopulmonary exercise test. Forward and Backward Digit Span scores significantly improved post-recovery compared with baseline measurements. There was a significant decrease in RAVLT scores post-exercise, which returned to baseline values after recovery. The DSST test scores were mildly elevated from post-exercise to after recovery. Maximal intensity exercise in children and adolescents may result in both beneficial and detrimental cognitive effects, including transient impairment in verbal learning. Cognitive functions applying short term memory improve following a recovery period. Parents, educators and coaches should consider these changes in memory and attention following high-intensity exercise activities in children.

Key words

  • neurocognitive
  • verbal learning
  • physical activity
  • short term memory
  • cognition
  • pediatrics
Open Access

Effects of an Elastic Hamstring Assistance Device During Downhill Running

Published Online: 22 Jun 2017
Page range: 73 - 83

Abstract

Abstract

The purpose of this study was to determine the appropriateness of using an elastic hamstring assistance device to reduce perceived levels of soreness, increase isometric strength, increase passive range of motion, and decrease biomarkers of muscle damage after eccentric exercise, specifically, downhill running This study was conducted in a university exercise physiology laboratory placing sixteen apparently healthy males (X = 21.6 ± 2.5 years) into two groups using a pre-test/post-test design. Pre-intervention measures taken included participants’ body height, body mass, body fat, capillary blood samples, VO2max, isometric hamstring strength at 45 and 90 degrees of flexion and passive hamstring range of motion. Post-intervention measures included blood biomarkers, passive range of motion, the perceived level of soreness and isometric strength. An analysis of normality of data was initially conducted followed by multivariate analysis of variance (MANOVA) of hamstring strength at 45 and 90 degrees of flexion, blood myoglobin and passive range of motion of the hamstrings. Statistically significant changes were noted in subject-perceived muscle soreness and isometric strength at 90 degrees at the 24-hour post-exercise trial measure between the two groups. Results would suggest the findings could be explained by the decrease in muscle soreness from utilizing the device during the exercise trial. Further research should be conducted to address sample size issues and to determine if the results are comparable on different surfaces.

Key words

  • soreness
  • isometrics
  • hamstring
  • myoglobin

Section III – Sports Training

Open Access

Performance Trends in Master Butterfly Swimmers Competing in the FINA World Championships

Published Online: 22 Jun 2017
Page range: 199 - 211

Abstract

Abstract

Performance trends in elite butterfly swimmers are well known, but less information is available regarding master butterfly swimmers. We investigated trends in participation, performance and sex differences in 9,606 female and 13,250 male butterfly race times classified into five-year master groups, from 25-29 to 90-94 years, competing in the FINA World Masters Championships between 1986 and 2014. Trends in participation were analyzed using linear regression analysis. Trends in performance changes were investigated using mixed-effects regression analyses with sex, distance and a calendar year as fixed variables. We also considered interaction effects between sex and distance. Participation increased in master swimmers older than ~30-40 years. The men-to-women ratio remained unchanged across calendar years and master groups, but was lower in 200 m compared to 50 m and 100 m. Men were faster than women from 25-29 to 85-89 years (p < 0.05), although not for 90-94 years. Sex and distance showed a significant interaction in all master groups from 25-29 to 90-94 years for 200m (p < 0.05). For 50 m and 100 m, a significant sex × distance interaction was observed from 25-29 to 75-79 years (p < 0.05), but not in the older groups. In 50 m, women reduced the sex difference in master groups 30-34 to 60-64 years (p < 0.05). In 100 m, women decreased the gap to men in master groups 35-39 to 55-59 years (p < 0.05). In 200 m, the sex difference was reduced in master groups 30-34 to 40-44 years (p < 0.05). In summary, women and men improved performance at all distances, women were not slower compared to men in the master group 90-94 years; moreover, women reduced the gap to men between ~30 and ~60 years, although not in younger or older master groups.

Key words

  • aging
  • master athletes
  • sex difference
  • swimming
Open Access

Assessment of Specificity of the Badcamp Agility Test for Badminton Players

Published Online: 22 Jun 2017
Page range: 191 - 198

Abstract

Abstract

The Badcamp agility test was created to evaluate agility of badminton players. The Badcamp is a valid and reliable test, however, a doubt about the need for the use of this test exists as simpler tests could provide similar information about agility in badminton players. Thus, the aim of this study was to examine the specificity of the Badcamp, comparing the performance of badminton players and athletes from other sports in the Badcamp and the shuttle run agility test (SRAT). Sixty-four young male and female athletes aged between 14 and 16 years participated in the study. They were divided into 4 groups of 16 according to their sport practices: badminton, tennis, team sport (basketball and volleyball), and track and field. We compared the groups in both tests, the Badcamp and SRAT. The results revealed that the group of badminton players was faster compared to all other groups in the Badcamp. However, in the SRAT there were no differences among groups composed of athletes from open skill sports (e.g., badminton, tennis, and team sports), and a considerable reduction of the difference between badminton players and track and field athletes. Thus, we concluded that the Badcamp test is a specific agility test for badminton players and should be considered in evaluating athletes of this sport modality.

Key words

  • badminton
  • racket
  • sport
  • quickness
  • uncertainty
  • reaction time
Open Access

Differences in Anthropometry, Biological Age and Physical Fitness Between Young Elite Kayakers and Canoeists

Published Online: 22 Jun 2017
Page range: 181 - 190

Abstract

Abstract

The aim of this study was to determine the anthropometric and physical characteristics of youth elite paddlers and to identify the differences between kayakers and canoeists. A total of 171 male paddlers (eighty-nine kayakers and eighty-two canoeists), aged 13.69 ± 0.57 years (mean ± SD) volunteered to participate in this study. The participants completed basic anthropometric assessments (body mass, stretch stature, sitting height, body mass index, maturity level, sum of 6 skinfolds and fat mass percentage) as well as a battery of physical fitness tests (overhead medicine ball throw, counter movement jump, sit-and-reach and 20 m multi-stage shuttle run tests). The anthropometric results revealed a significantly larger body size (stretch stature and sitting height) and body mass in the kayakers (p < 0.01) as well as a more mature biological status (p = 0.003). The physical fitness level exhibited by the kayakers was likewise significantly greater than that of the canoeists, both in the counter movement jump and estimated VO2max (p < 0.05), as well as in the overhead medicine ball throw and sit-and-reach test (p < 0.01). These findings confirm the more robust and mature profile of youth kayakers that might be associated with the superior fitness level observed and the specific requirements of this sport discipline.

Key words

  • anthropometry
  • physical fitness
  • biological age
  • kayak
  • canoe
Open Access

Anthropometric Profile in Different Event Categories of Acrobatic Gymnastics

Published Online: 22 Jun 2017
Page range: 169 - 179

Abstract

Abstract

There is a specific anthropometric profile for each sport, which may be differentiated even in relation to the position, role or event category within each sport discipline. However, there are few studies on acrobatic gymnastics, and the goal of this work was to determine the anthropometric profile depending on the event category, as well as factors that predisposed to performance in these categories. The sample consisted of 150 gymnasts from Spain, divided into 8 groups according to the event category and the role played. The kinanthropometric measurements were taken through the procedures established by the International Society for the Advancement of Kineantropometry. The anthropometric characteristics, including body mass index, somatotype, body composition and proportionality using the Phantom stratagem were analyzed, and the results obtained from the different groups were compared. A regression analysis was performed with particular groups of gymnasts. No significant differences (p < 0.05) were observed between groups of female tops or male bases, although differences were found between female group bases and female pair bases. It could be suggested that higher values of body height, sitting height, the minimum abdominal circumference, percentage of fat and low biliocristal breadth predispose female bases to work in pairs rather than in groups. The conclusion is that the anthropometric measurements are not decisive when guiding a gymnast toward choosing one event category or another, except for female bases.

Key words

  • morphological characteristics
  • phantom stratagem for proportionality assessment
  • body mass index
  • somatotype and body composition
Open Access

A Model for Determining the Effect of the Wind Velocity on 100 M Sprinting Performance

Published Online: 22 Jun 2017
Page range: 159 - 167

Abstract

Abstract

This paper introduces an equation for determining instantaneous and final velocity of a sprinter in a 100 m run completed with a wind resistance ranging from 0.1 to 4.5 m/s. The validity of the equation was verified using the data of three world class sprinters: Carl Lewis, Maurice Green, and Usain Bolt. For the given constant wind velocity with the values + 0.9 and + 1.1 m/s, the wind contribution to the change of sprinter velocity was the same for the maximum as well as for the final velocity. This study assessed how the effect of the wind velocity influenced the change of sprinting velocity. The analysis led to the conclusion that the official limit of safely neglecting the wind influence could be chosen as 1 m/s instead of 2 m/s, if the velocity were presented using three, instead of two decimal digits. This implies that wind velocity should be rounded off to two decimal places instead of the present practice of one decimal place. In particular, the results indicated that the influence of wind on the change of sprinting velocity in the range of up to 2 m/s and was of order of magnitude of 10-3 m/s. This proves that the IAAF Competition Rules correctly neglect the influence of the wind with regard to such velocities. However, for the wind velocity over 2 m/s, the wind influence is of order 10-2 m/s and cannot be neglected.

Key words

  • mathematical modelling
  • track sprinting
  • wind
Open Access

Quality Versus Quantity Debate in Swimming: Perceptions and Training Practices of Expert Swimming Coaches

Published Online: 22 Jun 2017
Page range: 147 - 158

Abstract

Abstract

The debate over low-volume, high-intensity training versus high-volume, low-intensity training, commonly known as Quality versus Quantity, respectively, is a frequent topic of discussion among swimming coaches and academics. The aim of this study was to explore expert coaches’ perceptions of quality and quantity coaching philosophies in competitive swimming and to investigate their current training practices. A purposeful sample of 11 expert swimming coaches was recruited for this study. The study was a mixed methods design and involved each coach participating in 1 semi-structured interview and completing 1 closed-ended questionnaire. The main findings of this study were that coaches felt quality training programmes would lead to short term results for youth swimmers, but were in many cases more appropriate for senior swimmers. The coaches suggested that quantity training programmes built an aerobic base for youth swimmers, promoted technical development through a focus on slower swimming and helped to enhance recovery from training or competition. However, the coaches continuously suggested that quantity training programmes must be performed with good technique and they felt this was a misunderstood element. This study was a critical step towards gaining a richer and broader understanding on the debate over Quality versus Quantity training from an expert swimming coaches’ perspective which was not currently available in the research literature.

Key words

  • high-intensity training
  • high-volume training
  • long term athlete development
  • coaching philosophy
  • mixed methods
Open Access

Intra-Subject Variability of 5 Km Time Trial Performance Completed by Competitive Trained Runners

Published Online: 22 Jun 2017
Page range: 139 - 146

Abstract

Abstract

Time-trials represent an ecologically valid approach to assessment of endurance performance. Such information is useful in the application of testing protocols and estimation of sample sizes required for research/magnitude based inference methods. The present study aimed to investigate the intra-subject variability of 5 km time-trial running performance in trained runners. Six competitive trained male runners (age = 33.8 ± 10.1 years; stature = 1.78 ± 0.01 m; body mass = 69.0 ± 10.4 kg, V. $\it V^{.}$ O2max = 62.6 ± 11.0 ml·kg·min-1) completed an incremental exercise test to volitional exhaustion followed by 5 x 5 km time-trials (including a familiarisation trial), individually spaced by 48 hours. The time taken to complete each trial, heart rate, rating of perceived exertion and speed were all assessed. Intra-subject absolute standard error of measurement and the coefficient of variance were calculated for time-trial variables in addition to the intra-class correlation coefficient for time taken to complete the time-trial. For the primary measure time, results showed a coefficient of variation score across all participants of 1.5 ± 0.59% with an intra-class correlation coefficient score of 0.990. Heart rate, rating of perceived exertion and speed data showed a variance range between 0.8 and 3.05%. It was concluded that when compared with related research, there was observed low intra-subject variability in trained runners over a 5 km distance. This supports the use of this protocol for 5 km time-trial performance for assessment of nutritional strategies, ergogenic aids or training interventions on endurance running performance.

Key words

  • endurance
  • running economy
  • reliability
Open Access

A Comparison of GPS Workload Demands in Match Play and Small-Sided Games by the Positional Role in Youth Soccer

Published Online: 22 Jun 2017
Page range: 129 - 137

Abstract

Abstract

The external demands of small-sided games (SSGs) according to the positional role are currently unknown. Using a Catapult Minimax X3 5 Hz GPS, with a 100 Hz tri-axial accelerometer, we compared the accumulated tri-axial player workload per min (PLacc·min-1) during friendly youth match play (MP) (11 vs. 11) and SSGs (2 vs. 2, 3 vs. 3, and 4 vs. 4). Significant differences existed between all SSGs and MP for PLacc·min-1 (F = 21.91, p < 0.001, η2 = 0.38), and individual X (F = 27.40, p < 0.001, η2 = 0.43), Y (F = 14.50, p < 0.001, η2 = 0.29) and Z (F = 19.28, p < 0.001, η2 = 0.35) axis loads. Across all conditions, mean PLacc·min-1 was greater for midfielders (p = 0.004, CI: 0.68, 4.56) and forwards (p = 0.037, CI: 0.08, 3.97) than central defenders. In all conditions, greater Y axis values existed for wide defenders (p = 0.024, CI: 0.67, 1.38), midfielders (p = 0.006, CI: 0.18, 1.50) and forwards (p = 0.007, CI: 0.17, 0.15) compared to central defenders. Midfielders reported greater Z axis values compared to central defenders (p = 0.002, CI: 0.40, 2.23). We concluded that SSGs elicited greater external loads than MP, and previous studies may have underestimated the demands of SSGs.

Key words

  • small sided games
  • training games
  • conditioning
  • soccer
  • player load
  • GPS
Open Access

A Rapidly-Incremented Tethered-Swimming Test for Defining Domain-Specific Training Zones

Published Online: 22 Jun 2017
Page range: 117 - 128

Abstract

Abstract

The purpose of this study was to investigate whether a tethered-swimming incremental test comprising small increases in resistive force applied every 60 seconds could delineate the isocapnic region during rapidly-incremented exercise. Sixteen competitive swimmers (male, n = 11; female, n = 5) performed: (a) a test to determine highest force during 30 seconds of all-out tethered swimming (Favg) and the ΔF, which represented the difference between Favg and the force required to maintain body alignment (Fbase), and (b) an incremental test beginning with 60 seconds of tethered swimming against a load that exceeded Fbase by 30% of ΔF followed by increments of 5% of ΔF every 60 seconds. This incremental test was continued until the limit of tolerance with pulmonary gas exchange (rates of oxygen uptake and carbon dioxide production) and ventilatory (rate of minute ventilation) data collected breath by breath. These data were subsequently analyzed to determine whether two breakpoints defining the isocapnic region (i.e., gas exchange threshold and respiratory compensation point) were present. We also determined the peak rate of O2 uptake and exercise economy during the incremental test. The gas exchange threshold and respiratory compensation point were observed for each test such that the associated metabolic rates, which bound the heavy-intensity domain during constant-work-rate exercise, could be determined. Significant correlations (Spearman’s) were observed for exercise economy along with (a) peak rate of oxygen uptake (ρ = .562; p < 0.025), and (b) metabolic rate at gas exchange threshold (ρ = −.759; p < 0.005). A rapidly-incremented tethered-swimming test allows for determination of the metabolic rates that define zones for domain-specific constant-work-rate training.

Key words

  • isocapnic region
  • gas exchange threshold
  • respiratory compensation point
  • exercise economy
  • constant-work-rate exercise
  • heavy intensity

Section IV – Behavioural Sciences in Sport

Open Access

The Relationship Between Perceived Coaching Behaviours, Motivation and Self-Efficacy in Wrestlers

Published Online: 22 Jun 2017
Page range: 239 - 251

Abstract

Abstract

The current study aimed to determine the relationship between perceived coaching behaviours, motivation, self-efficacy and general self-efficacy of wrestlers who competed in the Super National Wrestling League. The sample consisted of 289 wrestlers. The Self-Efficacy Scale was used to measure self-efficacy perception, the Sports Motivation Scale to measure the motivation of the athletes, the Leadership Scale for Sport to determine perceived leadership behaviours, and the General Self-Efficacy Scale to determine the general self-efficacy perceptions of the athletes. For data analyses, SPSS 17.0 software was used. According to the results of the regression analyses performed with the enter method, it was found that perceived training and instruction behaviour along with perceived social support behaviour significantly explained self-efficacy (adjusted R2_ = .03), intrinsic motivation (adjusted R2 = .04) and amotivation (adjusted R2 = .05). Also, perceived training and instruction behaviour (β = .51), autocratic behaviour (β = -.17) and social support behaviour (β = -.27) significantly contributed to athletes’ general self-efficacy (adjusted R2 = .10). In light of these findings, it may be argued that perceived training and instruction behaviour may be beneficial for self-efficacy, general self-efficacy, intrinsic motivation, and amotivation. On the other hand, it could be stated that perceived autocratic behaviour may be detrimental for general self-efficacy of the athletes. As for social support behaviour, it may be suggested that it is negatively related to self-efficacy, general self-efficacy and intrinsic motivation. Lastly, a positive relationship was observed between perceived social support behaviour and amotivation in wrestlers. The results reveal the specific characteristics of wrestlers and suggest some implications for wrestling coaches.

Key words

  • leadership
  • self-efficacy
  • motivation
  • coaching behaviours
  • wrestling
Open Access

Perceived Hindrances Experienced by Sport Coaches in South Africa

Published Online: 22 Jun 2017
Page range: 233 - 238

Abstract

Abstract

The purpose of this study was to examine perceived hindrances encountered by sport coaches in the Gauteng Province of South Africa. A total of 224 sport coaches (122 males and 102 females) were purposively recruited to participate in this study. An exploratory factor analysis was used to assess the factor structure of the Perceived Hindrance Scale. The results of this study indicated the following as major hindrances encountered by sport coaches: “Lack of support systems for women players”, “Lack of support for women coaches from superiors”, “Low salary”, “Lack of opportunities for promotion”, “Difficulties with parents/spectators” and “Lack of job security”. Recommendations on strategies to overcome these perceived hindrances are discussed.

Key words

  • coaching
  • hindrances
  • occupation
Open Access

Plantar Pressure Differences Between Nordic Walking Techniques

Published Online: 22 Jun 2017
Page range: 221 - 231

Abstract

Abstract

High plantar pressure has been associated with increased risk of injury. The characteristics of each physical activity determine the load on the lower limbs. The influence of Nordic Walking (NW) technique on plantar pressure is still unknown. The aim of this study was to analyze the differences between plantar pressure during NW with the Diagonal technique (DT) versus Alpha technique (AT) and compare them with the pressure obtained during normal walking (W). The normality and sphericity of the plantar pressure data were checked before performing a two-way repeated measures ANOVA in order to find differences between speeds (preferred, fast) and the gait (NW, W) as within-subject factors. Then, a t-test for independent measures was used to identify the specific differences between NW techniques. The strength of the differences was calculated by means of the effect size (ES). The results demonstrated that during NW with AT at preferred speed the pressure was lower under the Calcaneus, Lateral Metatarsal and Toes compared to the DT group (p = 0.046, ES = 1.49; p = 0.015, ES = 1.44; p = 0.040, ES = 1.20, respectively). No differences were found at the fast speed (p > 0.05). Besides the increase in walking speed during NW (p < 0.01), both technique groups showed lower pressure during NW compared to W under the Hallux and Central Metatarsal heads (F = 58.321, p = 0.000, ES = 2.449; F = 41.917, p = 0.012, ES = 1.365, respectively). As a practical conclusion, the AT technique may be the most effective of the NW techniques at reducing plantar pressure while allowing NW practitioners to achieve the physiological benefits of NW.

Key words

  • poles
  • biomechanics
  • foot
  • loading
Open Access

Home Advantage in Judo: Analysis by the Combat Phase, Penalties and the Type of Attack

Published Online: 22 Jun 2017
Page range: 213 - 220

Abstract

Abstract

Previous studies indicate positive home advantage in judo; however, the factors that influence home advantage have yet to be fully explored. This study investigated the potential differences in technical-tactical variables between home and visiting athletes. A total of 1411 video recorded matches were analyzed (123 home, 1288 away) from 36 international judo competitions contested in 2011-12. The matches were analyzed by the following criteria: combat phases (approach, gripping, attack, defense, groundwork and pause), penalties (by the athlete or the opponent) and the types of attacks (with or without a score). Elite judo athletes competing in their home country attacked more frequently using trunk/leg couple techniques (p < 0.011) and scored more frequently with arm/leg couple techniques (p < 0.001), while visiting judo athletes received fewer scores from penalties (p < 0.001) and engaged in more frequent pauses during competition (p < 0.01). The results of this study provide an outline of technical-tactical differences that may contribute to home advantage in judo.

Key words

  • home advantage
  • martial arts
  • performance analysis

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