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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 50 (2016): Issue 1 (April 2016)

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

Search

27 Articles

Research Article

Open Access

A Systematic Review of Psychological Studies Applied to Futsal

Published Online: 13 Apr 2016
Page range: 247 - 257

Abstract

Abstract

This study presents a systematic review of psychological studies applied to futsal. A total of 23 studies were analyzed within five sections: a year overview and the name of journals, research designs, data collection, sample characteristics, and a focus category. This study found that the first psychological articles that were applied to futsal were published in 2008, and the number of publications gradually increased since then. The majority of examined studies were cross-sectional designs and conducted at the elite level in European and Asian countries. Most studies did not use mixed methods and did not specify the age of the subjects. Psychological research applied to futsal focused on athletes, non-athletes and several psychological factors. Critical and innovative reflections were made to highlight research gaps and present suggestions for further research.

Key words

  • futsal study
  • research design
  • data collection
  • sample characteristics
Open Access

Case Study of Mental Skills Training for a Taekwondo Olympian

Published Online: 13 Apr 2016
Page range: 235 - 245

Abstract

Abstract

The purpose of this study was to identify the effect of systematic mental skills training (MST) for a taekwondo gold medallist. Based on MST of other sports, this programme was designed for a single subject who competed in the Olympics. The Korean test of performance strategies, Sport Attributional Style in Korean Athletes, and a few sessions of interviews were applied to investigate the effect of MST. The pre and post-test mean scores of both the Korean test of performance strategies and Sport Attributional Style in Korean Athletes were compared. Interviews recorded the athlete’s psychological characteristics. Excluding the ‘activation’ variable, all of the psychological skills, e.g. self-talk (4.25–5), emotional control (3.75–4.5), automaticity (3.75–4.25), goal setting (4.5–5), imagery (4.25–5), negative thinking (3.25–4.75), anxiety management (4.5–5), and physical and mental condition (4.5–5) improved. MST is believed to have helped the athlete succeed.

Key words

  • martial arts
  • combat
  • psychology
Open Access

Coaches’ Preferences for Continuing Coaching Education in South Africa

Published Online: 13 Apr 2016
Page range: 229 - 234

Abstract

Abstract

The purpose of this study was to examine coaches’ preferences for continuing coaching education. The sample consisted of 122 male and 102 female coaches from the Gauteng Province of South Africa who were purposively recruited to participate in this study. The results of this study showed that the coaches wanted to learn more about motivational techniques, advanced instructional drills, advanced first aid, goal setting, character building and conditioning drills. The results further indicated that sport coaches would be more likely to continue their coaching education if they had a desire to coach at a high level, if topics were relevant and if courses were in line with league requirements and were available online. The practical implications of the findings for the development of coaching education programmes in South Africa were discussed.

Key words

  • coaching
  • education
  • preferences
  • certification
Open Access

The El Dorado of Handball? Foreign Female Players Stay, while Domestic Players Return from Abroad

Published Online: 13 Apr 2016
Page range: 219 - 227

Abstract

Abstract

The main purpose of this research was to study the characteristics of migration in European women’s handball based on the Slovenian example and to find the differences between the foreigners coming to Slovenia and the Slovenians transferring to foreign clubs. The research was based on 16 open face-to-face semi-structured interviews (8 Slovenians (age 29.5 ± 6.2 years) and 8 foreigners (age 35.5 ± 8.7 years)). We found out that the most powerful factor in foreigners was the financial one, while within Slovenian players it was their personal desire for progression within their sport, the club’s reputation and poor conditions in their previous club. The results confirm that when making a decision on transfer, all players had the support of family and friends, while the clubs of foreign players were not as supportive. Most interviewees considered their careers successful and did not regret going abroad. The research indicates that the largest differences discovered between Slovenians and foreigners were that foreign female players chose to stay in the new country (Slovenia), while domestic players returned home after few years playing abroad. In conclusion, the results show that in top-level handball there are important differences between migration models which are based on nationality and also that the migration models change throughout time, which is largely connected with the socioeconomic events in the country of origin or transfer.

Key words

  • migration
  • characteristics
  • women
  • top-level handball
Open Access

The Activity Profile of Young Tennis Athletes Playing on Clay and Hard Courts: Preliminary Data

Published Online: 13 Apr 2016
Page range: 211 - 218

Abstract

Abstract

The aim of this study was to compare the kinematic characteristics of tennis matches between red clay and hard courts in young tennis players. Eight young tennis players performed two tennis matches on different court surfaces. The match activities were monitored using GPS units. The distance covered in different velocity ranges and the number of accelerations were analyzed. The paired t test and inference based on magnitudes were used to compare the match physical performance between groups. The total distance (24% of difference), high-intensity running distance (15 - 18 km/h) (30% of difference), the number of high-intensity activities (44% of difference), the body load (1% of difference), and accelerations >1.5 g (1.5-2 g and >2 g 7.8 and 8.1 % of difference, respectively) were significantly greater in clay court than hard court matches (p < 0.05). Matches played on the red clay court required players to cover more total and high-intensity running distances and engage in more high-intensity activities than the matches played on the hard court. Finally, on the clay court the body load and the number of accelerations performed (>1.5 g) were possibly higher than on the hard court.

Key words

  • kinematic analysis
  • GPS
  • racquet sports
  • accelerations
Open Access

Muscle Strength and Speed Performance in Youth Soccer Players

Published Online: 13 Apr 2016
Page range: 203 - 210

Abstract

Abstract

This study aimed to examine the relationship between maximum leg extension strength and sprinting performance in youth elite male soccer players. Sixty-three youth players (12.5 ± 1.3 years) performed 5 m, flying 15 m and 20 m sprint tests and a zigzag agility test on a grass field using timing gates. Two days later, subjects performed a one-repetition maximum leg extension test (79.3 ± 26.9 kg). Weak to strong correlations were found between leg extension strength and the time to perform 5 m (r = -0.39, p = 0.001), flying 15 m (r = -0.72, p < 0.001) and 20 m (r = -0.67, p < 0.001) sprints; between body mass and 5 m (r = -0.43, p < 0.001), flying 15 m (r = -0.75, p < 0.001), 20 m (r = -0.65, p < 0.001) sprints and agility (r =-0.29, p < 0.001); and between height and 5 m (r = -0.33, p < 0.01) and flying 15 m (r = -0.74, p < 0.001) sprints. Our results show that leg muscle strength and anthropometric variables strongly correlate with sprinting ability. This suggests that anthropometric characteristics should be considered to compare among youth players, and that youth players should undergo strength training to improve running speed.

Key words

  • sprint
  • maturation
  • strength training
  • soccer
  • youth players
  • development
Open Access

The Impact of a Good Season Start on Team Performance in Elite Handball

Published Online: 13 Apr 2016
Page range: 195 - 202

Abstract

Abstract

The aim of the current study was (i) to identify how important was a good season start in relation to elite handball teams’ performance, and (ii) to examine if this impact was related to the clubs’ financial budget. The match performances and annual budgets of all teams were collected from the Spanish Professional Handball League during ten seasons. The dependent variable was the difference between the ranking of each team in accordance to the annual budget and the ranking of each team at the end of the season. A k-means cluster analysis classified the clubs according to their budget as High Range Budget Clubs (HRBC), Upper-Mid Range Budget Clubs (UMRBC), Lower-Mid Range Budget Clubs (LMRBC) and Low Range Budget Clubs (LRBC). Data were examined through linear regression models. Overall, the results suggested that the better the team performance at the beginning of the season, the better the ranking at the end of the season. Each position in the ranking above expected in accordance to the budget of the teams in Rounds 3, 4 or 5 improved by 0.47, 0.50 or 0.49, respectively, in the ranking at the end of the season (p<0.05). However, the impact of the effect depended on the clubs’ annual budget. For UMRBC, LMRBC and LRBC a good start to the season had a positive effect on the final outcome (p<0.05). Nevertheless, for HRBC, a good or a bad start of the season did not explain their final position. These variables can be used to develop accurate models to estimate final rankings. UMRBC, LMRBC and LRBC can benefit from fine-tuning preseason planning in order to accelerate the acquisition of optimal performances.

Key words

  • handball
  • financial capacity
  • team performance
  • initial results
Open Access

Indirect Methods of Assessing Maximal Oxygen Uptake in Rowers: Practical Implications for Evaluating Physical Fitness in a Training Cycle

Published Online: 13 Apr 2016
Page range: 187 - 194

Abstract

Abstract

The aim of the study was to evaluate the usefulness of indirect methods of assessment of VO2max for estimation of physical capacity of trained male and female rowers during a training cycle. A group of 8 female and 14 male rowers performed the maximal intensity test simulating the regatta distance (a 2 km test) and a submaximal incremental exercise test on a rowing ergometer. The suitability of the indirect methods of predicting VO2max during the training cycle was evaluated by performing the tests twice: in females at an interval of five months and in males at an interval of seven months. To indirectly estimate VO2max, regression formulas obtained for the linear relationship between the examined effort indices were utilized based on 1) mean power obtained in the 2 km test, and 2) submaximal exercises after the estimation of PWC170. Although the suitability of the two indirect methods of assessment of VO2max was statisticaly confirmed, their usefulness for estimation of changes in physical fitness of trained rowers during the training cycle was rather low. Such an opinion stems from the fact that the total error of these methods (range between 4.2-7.7% in female and 5.1-7.4% in male rowers) was higher than the real differences in VO2max values determined in direct measurements (between the first and the second examination maximal oxygen uptake rose by 3.0% in female rowers and decreased by 4.3% in male rowers).

Key words

  • rowing ergometer
  • indirect methods
  • VO2max
  • training cycle
Open Access

Acute Effect of Different Combined Stretching Methods on Acceleration and Speed in Soccer Players

Published Online: 13 Apr 2016
Page range: 179 - 186

Abstract

Abstract

The purpose of this study was to investigate the acute effect of different stretching methods, during a warm-up, on the acceleration and speed of soccer players. The acceleration performance of 20 collegiate soccer players (body height: 177.25 ± 5.31 cm; body mass: 65.10 ± 5.62 kg; age: 16.85 ± 0.87 years; BMI: 20.70 ± 5.54; experience: 8.46 ± 1.49 years) was evaluated after different warm-up procedures, using 10 and 20 m tests. Subjects performed five types of a warm-up: static, dynamic, combined static + dynamic, combined dynamic + static, and no-stretching. Subjects were divided into five groups. Each group performed five different warm-up protocols in five non-consecutive days. The warm-up protocol used for each group was randomly assigned. The protocols consisted of 4 min jogging, a 1 min stretching program (except for the no-stretching protocol), and 2 min rest periods, followed by the 10 and 20 m sprint test, on the same day. The current findings showed significant differences in the 10 and 20 m tests after dynamic stretching compared with static, combined, and no-stretching protocols. There were also significant differences between the combined stretching compared with static and no-stretching protocols. We concluded that soccer players performed better with respect to acceleration and speed, after dynamic and combined stretching, as they were able to produce more force for a faster execution.

Key words

  • combined stretching
  • soccer
  • acceleration
  • speed
  • warm-up
Open Access

Investigating the Effects of Typical Rowing Strength Training Practices on Strength and Power Development and 2,000 m Rowing Performance

Published Online: 13 Apr 2016
Page range: 167 - 177

Abstract

Abstract

This study aimed to determine the effects of a short-term, strength training intervention, typically undertaken by club-standard rowers, on 2,000 m rowing performance and strength and power development. Twenty-eight male rowers were randomly assigned to intervention or control groups. All participants performed baseline testing involving assessments of muscle soreness, creatine kinase activity (CK), maximal voluntary contraction (leg-extensors) (MVC), static-squat jumps (SSJ), counter-movement jumps (CMJ), maximal rowing power strokes (PS) and a 2,000 m rowing ergometer time-trial (2,000 m) with accompanying respiratory-exchange and electromyography (EMG) analysis. Intervention group participants subsequently performed three identical strength training (ST) sessions, in the space of five days, repeating all assessments 24 h following the final ST. The control group completed the same testing procedure but with no ST. Following ST, the intervention group experienced significant elevations in soreness and CK activity, and decrements in MVC, SSJ, CMJ and PS (p < 0.01). However, 2,000 m rowing performance, pacing strategy and gas exchange were unchanged across trials in either condition. Following ST, significant increases occurred for EMG (p < 0.05), and there were non-significant trends for decreased blood lactate and anaerobic energy liberation (p = 0.063 – 0.086). In summary, club-standard rowers, following an intensive period of strength training, maintained their 2,000 m rowing performance despite suffering symptoms of muscle damage and disruption to muscle function. This disruption likely reflected the presence of acute residual fatigue, potentially in type II muscle fibres as strength and power development were affected.

Key words

  • recovery
  • muscle function
  • muscle damage
  • resistance training
  • endurance performance
Open Access

The Relationship Between the Lower-Body Muscular Profile and Swimming Start Performance

Published Online: 13 Apr 2016
Page range: 157 - 165

Abstract

Abstract

This study aimed to examine the correlation of different dry land strength and power tests with swimming start performance. Twenty international level female swimmers (age 15.3 ± 1.6 years, FINA point score 709.6 ± 71.1) performed the track freestyle start. Additionally, dry land tests were conducted: a) squat (SJ) and countermovement jumps (CMJ), b) squat jumps with additional resistance equivalent to 25, 50, 75 and 100% of swimmers’ body weight [BW]), and c) leg extension and leg flexion maximal voluntary isometric contractions. Correlations between dry land tests and start times at 5, 10 and 15 m were quantified through Pearson’s linear correlation coefficients (r). The peak bar velocity reached during the jumps with additional resistance was the variable most correlated to swimming start performance (r = -0.57 to -0.66 at 25%BW; r = -0.57 to -0.72 at 50%BW; r = -0.59 to -0.68 at 75%BW; r = -0.50 to - 0.64 at 100%BW). A few significant correlations between the parameters of the SJ and the CMJ with times of 5 and 10 m were found, and none with the isometric variables. The peak velocity reached during jumps with external loads relative to BW was found a good indicator of swimming start performance.

Key words

  • swim start
  • freestyle swimming
  • dry land test
  • jumps with additional resistance
  • isometric test
Open Access

Preseason Strategies of Italian First League Soccer Clubs in Relation to their Championship Ranking: A Five-Year Analysis

Published Online: 13 Apr 2016
Page range: 145 - 155

Abstract

Abstract

This study is focused on the strategies adopted by Italian ‘Serie A’ soccer clubs during the non-competitive period. Thus, duration (i.e., number of days) of the specific non-competitive periods (i.e., off- plus pre-season, off-season, pre-season, summer camp), the number of games (i.e., friendly, official and polled games) and days between games (i.e., ≤ 3, 4-5, or ≥ 6 days between two consecutive games) of the entire non-competitive period were recorded and compared by clubs participating in the European Championships (EU), only ‘Serie A’ (A) and promoted from ‘Serie B’ (B) during five and single seasons (i.e., 2009/10-2013/14). Due to the short B off-season duration (2009/10-2013/14, 2010/11, 2011/12, 2012/13, 2013/14, p≤.001), effects between clubs emerged also for the off- plus preseason (2009/10-2013/14, EU vs A, p≤.01, EU vs B, p≤.01, A vs B, p≤.001; 2011/12, 2012/13, 2013/14, p≤.001). Nevertheless, no difference between clubs resulted for the pre-season. Reduced duration of summer camps was reported by the EU (i.e., 2009/10-2013/14, 2009/10, 2013/14, p≤.001). A higher number of official games were played by EU than A (i.e., 2009/10-2013/14, p≤.001; 2010/11, p≤.01). No effect emerged for the days between games. Therefore, despite the longer ‘Serie B’ schedule and EU preliminary UEFA games that determined the off-season restriction, clubs demonstrated the tendency to guarantee satisfactory pre-season duration.

Key words

  • team sports periodization
  • Italian soccer first league
  • summer training camp
Open Access

Lower Limb Neuromuscular Asymmetry in Volleyball and Basketball Players

Published Online: 13 Apr 2016
Page range: 135 - 143

Abstract

Abstract

The primary objective of the present study was to evaluate the agreement between the dominant leg (DL) (determined subjectively) and the stronger leg (SL) (determined via a functional test) in a group of basketball and volleyball players. The secondary objective was to calculate lower limb neuromuscular asymmetry when comparing the DL vs the non-dominant leg (NDL) and the SL vs the weaker (WL) leg in the whole group and when differentiating by sex. Seventy-nine male and female volleyball and basketball players (age: 23.7 ± 4.5 years) performed three single-leg vertical countermovement jumps (SLVCJ) on a contact mat. Vertical jump height and an inter-limb asymmetry index (ASI) were determined. Only 32 (40%) of the subjects had a concordance between the perception of their dominant leg and the limb reaching the highest jump height. Using the DL as the discriminating variable, significant (p<0.05) inter-limb differences were found in the total group of players. When comparing between sexes, significant differences (p<0.05) arose in the female group only. With regard to the WL vs. the SL, significant (p<0.05) differences were noted in the whole group and when stratified into males and females. The mean ASI ranged from 9.31% (males) to 12.84% (females) and from 10.49% (males) to 14.26% (females), when comparing the DL vs. the NDL and the SL vs. the WL, respectively. Subjective expression of leg dominance cannot be used as a predictor of limb jump performance. Vertical jump asymmetry of 10-15% exists and this can be considered as a reference value for male and female basketball and volleyball players.

Key words

  • power
  • unilateral
  • imbalances
  • alpinist expedition
  • team sport games
Open Access

The Influence of High-Altitude Acclimatization on Ventilatory and Blood Oxygen Saturation Responses During Normoxic and Hypoxic Testing

Published Online: 13 Apr 2016
Page range: 125 - 133

Abstract

Abstract

We investigated how acclimatization effects achieved during a high-altitude alpinist expedition influence endurance performance, ventilation (V˙E${\dot V_E}$) and blood oxygen saturation (SaO2) in normoxic (NOR) and hypoxic conditions (HYP). An incremental testing protocol on a cycle ergometer was used to determine the power output corresponding to the Lactate (PLT) and Ventilatory Threshold (PVT) in NOR and HYP (FiO2=0.13) as indirect characteristics of endurance performance in both conditions. Furthermore, changes in V˙E${\dot V_E}$, SaO2, blood pH and Pco2 were measured at a similar absolute exercise intensity of 180 W in NOR and HYP conditions. Seven experienced alpinists (mean ± SD: age: 50 ± 6 yrs; body mass: 76 ± 5 kg; body height: 175 ± 8 cm) volunteered to participate in this study after they had reached the summit of Gasherbrum II and Ama Dablam. They had therefore experienced the limitations of their acclimatization. Individual differences of PLT between values reached after and before the expedition (∆PLT) correlated (r = 0.98, p = 0.01) with differences of SaO2 (∆SaO2) in HYP, and differences of PVT (∆PVT) correlated (r = -0.83, p = 0.02) with differences of V˙E(ΔV˙E)${\dot V_E}\left( {\Delta {{\dot V}_E}} \right)$ in HYP. The results suggest that the acclimatization may not have an equivocal and simple influence on the performance in hypoxia: enhanced blood oxygen saturation may be accompanied by increased endurance only, when the increase exceeded 2-3%, but enhanced ventilation, when increased more than 10 l/min in HYP, could detrimentally influence endurance.

Key words

  • hypoxia
  • normoxia
  • acclimatization
  • alpinist expedition
  • endurance
Open Access

Influence of Physiological Loading on the Lumbar Spine of National Level Athletes in Different Sports

Published Online: 13 Apr 2016
Page range: 115 - 123

Abstract

Abstract

The lumbar spine is subjected to considerable stress during many athletic efforts. The purpose of this study was to assess the effects of physiological loading on the lumbar spine in national male players of different games, which may be predictive of the future development of low back pain and injury symptoms. Thirty-four national players (12 cricket players, 12 field hockey players, and 10 basketball players) underwent magnetic resonance imaging, and selected geometric variables including intervertebral disc angles, the Farfan ratio, the lumbar body index, the compression deformity ratio, the biconcave deformity ratio and the anterior wedge deformity ratio were measured using KINOVEA-0.8.15 software and syngo fast view software and calculated using specific formulas. The results indicated a significant difference in the intervertebral disc angle between the three groups at the L2/3, L3/4 and L4/5 levels. In relation to the lumbar vertebral body shape and size, significant differences were found in the lumbar index at the L2 level, in the biconcave deformity at the L1 and L2 levels and in relation to the anterior wedge deformity at L2 between the three selected groups. Our data suggest that the different physiological loadings in the selected sports play an important role in the development of degenerative changes of the lumbar spine, which may be considered a risk factor for future injury and/or low back pain in each specific sport because of the unique demands of each discipline.

Key words

  • degenerative changes
  • magnetic resonance imaging
  • basketball
  • cricket
  • field hockey
Open Access

Application of A Physiological Strain Index in Evaluating Responses to Exercise Stress – A Comparison Between Endurance and High Intensity Intermittent Trained Athletes

Published Online: 13 Apr 2016
Page range: 103 - 114

Abstract

Abstract

The study evaluated differences in response to exercise stress between endurance and high-intensity intermittent trained athletes in a thermoneutral environment using a physiological strain index (PSI). Thirty-two subjects participated in a running exercise under normal (23°C, 50% RH) conditions. The group included nine endurance trained athletes (middle-distance runners - MD), twelve high-intensity intermittent trained athletes (soccer players - HIIT) and eleven students who constituted a control group. The exercise started at a speed of 4 km·h–1 which was increased every 3 min by 2 km·h–1 to volitional exhaustion. The heart rate was recorded with a heart rate monitor and aural canal temperature was measured using an aural canal temperature probe. The physiological strain index (PSI) and the contribution of the circulatory and thermal components to the overall physiological strain were calculated from the heart rate and aural canal temperature. The physiological strain index differed between the study and control participants, but not between the MD and HIIT groups. The physiological strain in response to exercise stress in a thermoneutral environment was mainly determined based on the circulatory strain (MD group - 73%, HIIT group – 70%). The contribution of the circulatory and thermal components to the physiological strain did not differ significantly between the trained groups (MD and HIIT) despite important differences in morphological characteristics and training-induced systemic cardiovascular and thermoregulatory adaptations.

Key words

  • physiological strain
  • exercise
  • adaptation
  • thermoneutral conditions
  • athletes
Open Access

Differences in Physiological Responses to Interval Training in Cyclists With and Without Interval Training Experience

Published Online: 13 Apr 2016
Page range: 93 - 101

Abstract

Abstract

The aim of this study was to determine differences in glycolytic metabolite concentrations and work output in response to an all-out interval training session in 23 cyclists with at least 2 years of interval training experience (E) and those inexperienced (IE) in this form of training. The intervention involved subsequent sets of maximal intensity exercise on a cycle ergometer. Each set comprised four 30 s repetitions interspersed with 90 s recovery periods; sets were repeated when blood pH returned to 7.3. Measurements of post-exercise hydrogen (H+) and lactate ion (LA-) concentrations and work output were taken. The experienced cyclists performed significantly more sets of maximal efforts than the inexperienced athletes (5.8 ± 1.2 vs. 4.3 ± 0.9 sets, respectively). Work output decreased in each subsequent set in the IE group and only in the last set in the E group. Distribution of power output changed only in the E group; power decreased in the initial repetitions of set only to increase in the final repetitions. H+ concentration decreased in the third, penultimate, and last sets in the E group and in each subsequent set in the IE group. LA- decreased in the last set in both groups. In conclusion, the experienced cyclists were able to repeatedly induce elevated levels of lactic acidosis. Power output distribution changed with decreased acid–base imbalance. In this way, this group could compensate for a decreased anaerobic metabolism. The above factors allowed cyclists experienced in interval training to perform more sets of maximal exercise without a decrease in power output compared with inexperienced cyclists.

Key words

  • maximal glycolytic exercise
  • lactic acidosis
  • training load
Open Access

Within-Session Stability of Short-Term Heart Rate Variability Measurement

Published Online: 13 Apr 2016
Page range: 85 - 92

Abstract

Abstract

The primary aim of this study was to assess the retest stability of the short-term heart rate variability (HRV) measurement performed within one session and without the use of any intervention. Additionally, a precise investigation of the possible impact of intrinsic biological variation on HRV reliability was also performed. First, a single test-retest HRV measurement was conducted with 20-30 min apart from one another. Second, the HRV measurement was repeated in ten non-interrupted consecutive intervals. The lowest typical error (CV = 21.1%) was found for the square root of the mean squared differences of successive RR intervals (rMSSD) and the highest for the low frequency power (PLF) (CV = 93.9%). The standardized changes in the mean were trivial to small. The correlation analysis revealed the highest level for ln rMSSD (ICC = 0.87), while ln PLF represented the worst case (ICC = 0.59). The reliability indices for ln rMSSD in 10 consecutive intervals improved (CV = 9.9%; trivial standardized changes in the mean; ICC = 0.96). In conclusion, major differences were found in the reliability level between the HRV indices. The rMSSD demonstrated the highest reliability level. No substantial influence of intrinsic biological variation on the HRV reliability was observed.

Key words

  • heart rate variability
  • reliability
  • typical error
  • autonomic nervous system
Open Access

Prevalence of Dehydration Before Training Sessions, Friendly and Official Matches in Elite Female Soccer Players

Published Online: 13 Apr 2016
Page range: 79 - 84

Abstract

Abstract

This study aimed to evaluate and compare the hydration states prior to different sporting events (training sessions, friendly and official matches) in elite female soccer players and relate that to the importance that the player attached to the hydration state as a determinant of sports performance. The hydration state of 17 female elite soccer players (age: 21.5 ± 3 years; body mass: 62 ± 6 kg; body height: 165 ± 9 cm) was determined by measuring their urine specific gravity (USG) prior to three different sports events: training sessions (PT), friendly (PF) and official (PO) matches. The importance that each player attached to the hydration state as a determinant of sports performance was evaluated through a simple questionnaire. An average of 47.05% of the soccer players were severely dehydrated (USG > 1.030), 33.33% were significantly dehydrated (USG > 1.020), 17.64% were mildly dehydrated (USG > 1.010) and 1.96% were euhydrated (USG < 1.010). The average USG was 1.027 ± 0.007 (PT = 1.029 ± 0.009; PF = 1.023 ± 0.010 and PO = 1.030 ± 0.006). Differences were found between urine specific gravity prior to a friendly and an official match (p = 0.03). No relationship was found between urine specific gravity and the importance each player attached to the hydration state as a determinant of sports performance. The results show that dehydration is the most prevalent hydration state of elite soccer players before training sessions, friendly and official matches. Players were most dehydrated prior to official matches, which was unlinked to the players’ perceived importance of hydration for sports performance.

Key words

  • dehydration
  • soccer
  • hydration
  • female player
Open Access

25(OH)D3 Levels Relative to Muscle Strength and Maximum Oxygen Uptake in Athletes

Published Online: 13 Apr 2016
Page range: 71 - 77

Abstract

Abstract

Vitamin D is mainly known for its effects on the bone and calcium metabolism. The discovery of Vitamin D receptors in many extraskeletal cells suggests that it may also play a significant role in other organs and systems. The aim of our study was to assess the relationship between 25(OH)D3 levels, lower limb isokinetic strength and maximum oxygen uptake in well-trained professional football players. We enrolled 43 Polish premier league soccer players. The mean age was 22.7±5.3 years. Our study showed decreased serum 25(OH)D3 levels in 74.4% of the professional players. The results also demonstrated a lack of statistically significant correlation between 25(OH)D3 levels and lower limb muscle strength with the exception of peak torque of the left knee extensors at an angular velocity of 150°/s (r=0.41). No significant correlations were found between hand grip strength and maximum oxygen uptake. Based on our study we concluded that in well-trained professional soccer players, there was no correlation between serum levels of 25(OH)D3 and muscle strength or maximum oxygen uptake.

Key words

  • vitamin D
  • muscle strength
  • VO
  • athletes
Open Access

Two-Man Bobsled Push Start Analysis

Published Online: 13 Apr 2016
Page range: 63 - 70

Abstract

Abstract

The importance of push start times on bobsled performance was evidenced by some studies, but at this moment there is no article to the authors’ knowledge that describes the bobsled push start. Thus, the objectives of this study were to describe the two-man bobsled push start, analyze the differences between teams, and estimate the most important variable analyzed. We hypothesized that the pilot and brakeman athletes’ movement patterns during a bobsled pushing start can be described. The images used in this study were obtained during the men’s two-man XIV World Championship of Bobsled (2004). Fifteen best teams participating in the championship were recorded, and four start runs for each team were analyzed. The videos were captured by two digital video cameras. The pilot athletes were analyzed during the moment that they touched the lateral push bar of the sled, and the brakemen were analyzed during the first take-off and first landing. The teams were pooled in three groups of five teams using the final ranking of pushing time. We concluded that there was a distinct pattern movement for pilots and brakemen. The initial position of the majority of the pilots was localized slightly behind the bar. After touching the lateral bar, the pilots remained in a semi-squat position, pushing the sled forward in a pattern of marching movement. All brakemen used the board attached to the track as a support for both feet at the start. The brakeman gave the greatest contribution to break the inertia of the sled. There was no significant difference of movement between the three groups analyzed for the pilot and the brakeman.

Key words

  • bobsleigh
  • winter sport
  • biomechanics
Open Access

Three-Dimensional Motion Analysis of Lumbopelvic Rhythm During Trunk Extension

Published Online: 13 Apr 2016
Page range: 53 - 62

Abstract

Abstract

Hip–spine coordination, known as the lumbopelvic rhythm, can be expressed as the lumbar–hip ratio. The lumbopelvic rhythm and lumbar–hip ratio can be used to assess lower limb function. We clarified the lumbopelvic rhythm and lumbar–hip ratio during trunk extension. We established a novel set of marker positions for three-dimensional motion analysis to assess the lumbar spinal angle. The original markers were placed on both paravertebral muscle groups at the 11th thoracic spinous process level, the 10th and 12th thoracic spinous processes, and the pelvis. We measured angle data during trunk extension using three-dimensional motion analysis, and the data for eight healthy male subjects were categorized into backward and forward phases. The lumbar–hip ratio increased significantly from 1.2 to 1.9 (mean, 1.6) in the backward phase, indicating considerable movement of the lumbar spine compared with hip movement in the latter phase. In the forward phase, the ratio decreased significantly from 1.9 to 0.5 (mean, 1.5). After completion of 80% of the forward phase, the lumbar–hip ratio decreased to <1.0. The lumbopelvic rhythm for trunk extension was better expressed by a cubic or quadratic function than a linear function. According to a linear function, when the hip extends by 1°, lumbar spine extends by 1.9°. Therefore, lumbar spinal movement was greater than hip movement in the sagittal plane. The implication of the curved line would indicate lumbar extension instead of the limitation of hip extension.

Key words

  • lumbopelvic rhythm
  • lumbar–hip ratio
  • lumbar spine angle
  • hip angle
  • trunk extension
Open Access

Balance Maintenance in the Upright Body Position: Analysis of Autocorrelation

Published Online: 13 Apr 2016
Page range: 45 - 52

Abstract

Abstract

The present research aimed to analyze values of the autocorrelation function measured for different time values of ground reaction forces during stable upright standing. It was hypothesized that if recording of force in time depended on the quality and way of regulating force by the central nervous system (as a regulator), then the application of autocorrelation for time series in the analysis of force changes in time function would allow to determine regulator properties and its functioning. The study was performed on 82 subjects (students, athletes, senior and junior soccer players and subjects who suffered from lower limb injuries). The research was conducted with the use of two Kistler force plates and was based on measurements of ground reaction forces taken during a 15 s period of standing upright while relaxed. The results of the autocorrelation function were statistically analyzed. The research revealed a significant correlation between a derivative extreme and velocity of reaching the extreme by the autocorrelation function, described as gradient strength. Low correlation values (all statistically significant) were observed between time of the autocorrelation curve passing through 0 axis and time of reaching the first peak by the said function. Parameters computed on the basis of the autocorrelation function are a reliable means to evaluate the process of flow of stimuli in the nervous system. Significant correlations observed between the parameters of the autocorrelation function indicate that individual parameters provide similar properties of the central nervous system.

Key words

  • lateralization
  • lower limbs
  • force
  • balance
  • autocorrelation
Open Access

Maximum Velocities in Flexion and Extension Actions for Sport

Published Online: 13 Apr 2016
Page range: 37 - 44

Abstract

Abstract

Speed of movement is fundamental to the outcome of many human actions. A variety of techniques can be implemented in order to maximise movement speed depending on the goal of the movement, constraints, and the time available. Knowing maximum movement velocities is therefore useful for developing movement strategies but also as input into muscle models. The aim of this study was to determine maximum flexion and extension velocities about the major joints in upper and lower limbs. Seven university to international level male competitors performed flexion/extension at each of the major joints in the upper and lower limbs under three conditions: isolated; isolated with a countermovement; involvement of proximal segments. 500 Hz planar high speed video was used to calculate velocities. The highest angular velocities in the upper and lower limb were 50.0 rad·s-1 and 28.4 rad·s-1, at the wrist and knee, respectively. As was true for most joints, these were achieved with the involvement of proximal segments, however, ANOVA analysis showed few significant differences (p<0.05) between conditions. Different segment masses, structures and locations produced differing results, in the upper and lower limbs, highlighting the requirement of segment specific strategies for maximal movements.

Key words

  • maximal
  • angular
  • velocity
  • movement pattern
Open Access

Spatiotemporal Parameters are not Substantially Influenced by Load Carriage or Inclination During Treadmill and Overground Walking

Published Online: 13 Apr 2016
Page range: 27 - 35

Abstract

Abstract

Influences of load carriage and inclination on spatiotemporal parameters were examined during treadmill and overground walking. Ten soldiers walked on a treadmill and overground with three load conditions (00 kg, 20 kg, 40 kg) during level, uphill (6% grade) and downhill (-6% grade) inclinations at self-selected speed, which was constant across conditions. Mean values and standard deviations for double support percentage, stride length and a step rate were compared across conditions. Double support percentage increased with load and inclination change from uphill to level walking, with a 0.4% stance greater increase at the 20 kg condition compared to 00 kg. As inclination changed from uphill to downhill, the step rate increased more overground (4.3 ± 3.5 steps/min) than during treadmill walking (1.7 ± 2.3 steps/min). For the 40 kg condition, the standard deviations were larger than the 00 kg condition for both the step rate and double support percentage. There was no change between modes for step rate standard deviation. For overground compared to treadmill walking, standard deviation for stride length and double support percentage increased and decreased, respectively. Changes in the load of up to 40 kg, inclination of 6% grade away from the level (i.e., uphill or downhill) and mode (treadmill and overground) produced small, yet statistically significant changes in spatiotemporal parameters. Variability, as assessed by standard deviation, was not systematically lower during treadmill walking compared to overground walking. Due to the small magnitude of changes, treadmill walking appears to replicate the spatiotemporal parameters of overground walking.

Key words

  • gait
  • uphill
  • downhill
  • external load
Open Access

Explosive Strength of the Knee Extensors: The Influence of Criterion Trial Detection Methodology on Measurement Reproducibility

Published Online: 13 Apr 2016
Page range: 15 - 25

Abstract

Abstract

The present study was conducted to assess test-retest reproducibility of explosive strength measurements during single-joint isometric knee extension using the IsoMed 2000 dynamometer. Thirty-one physically active male subjects (mean age: 23.7 years) were measured on two occasions separated by 48–72 h. The intraclass correlation coefficient (ICC 2,1) and the coefficient of variation (CV) were calculated for (i) maximum torque (MVC), (ii) the peak rate of torque development (RTDpeak) as well as for (iii) the average rate of torque development (RTD) and the impulse taken at several predefined time intervals (0–30 to 0–300 ms); thereby explosive strength variables were derived in two conceptually different versions: on the one hand from the MVC-trial (version I), on the other hand from the trial showing the RTDpeak (version II). High ICC-values (0.80–0.99) and acceptable CV-values (1.9–8.7%) could be found for MVC as well as for the RTD and the impulse taken at time intervals of ≥100 ms, regardless of whether version I or II was used. In contrast, measurements of the RTDpeak as well as the RTD and the impulse taken during the very early contraction phase (i.e. RTD/impulse0–30ms and RTD/impulse0–50ms) showed clearly weaker reproducibility results (ICC: 0.53–0.84; CV: 7.3–16.4%) and gave rise to considerable doubts as to clinical usefulness, especially when derived using version I. However, if there is a need to measure explosive strength for earlier time intervals in practice, it is, in view of stronger reproducibility results, recommended to concentrate on measures derived from version II, which is based on the RTDpeak-trial.

Key words

  • explosive torque production
  • rate of torque development
  • impulse
  • knee extension
  • IsoMed 2000
  • test-retest reproducibility
Open Access

Transferability between Isolated Joint Torques and a Maximum Polyarticular Task: A Preliminary Study

Published Online: 13 Apr 2016
Page range: 5 - 14

Abstract

Abstract

The aims of this study were to determine if isolated maximum joint torques and joint torques during a maximum polyarticular task (i.e. cycling at maximum power) are correlated despite joint angle and velocity discrepancies, and to assess if an isolated joint-specific torque production capability at slow angular velocity is related to cycling power. Nine cyclists completed two different evaluations of their lower limb maximum joint torques. Maximum Isolated Torques were assessed on isolated joint movements using an isokinetic ergometer and Maximum Pedalling Torques were calculated at the ankle, knee and hip for flexion and extension by inverse dynamics during cycling at maximum power. A correlation analysis was made between Maximum Isolated Torques and respective Maximum Pedalling Torques [3 joints x (flexion + extension)], showing no significant relationship. Only one significant relationship was found between cycling maximum power and knee extension Maximum Isolated Torque (r=0.68, p<0.05). Lack of correlations between isolated joint torques measured at slow angular velocity and the same joint torques involved in a polyarticular task shows that transfers between both are not direct due to differences in joint angular velocities and in mono-articular versus poly articular joint torque production capabilities. However, this study confirms that maximum power in cycling is correlated with slow angular velocity mono-articular maximum knee extension torque.

Key words

  • cycling
  • isokinetic ergometer
  • inverse dynamics
  • force-velocity test
27 Articles

Research Article

Open Access

A Systematic Review of Psychological Studies Applied to Futsal

Published Online: 13 Apr 2016
Page range: 247 - 257

Abstract

Abstract

This study presents a systematic review of psychological studies applied to futsal. A total of 23 studies were analyzed within five sections: a year overview and the name of journals, research designs, data collection, sample characteristics, and a focus category. This study found that the first psychological articles that were applied to futsal were published in 2008, and the number of publications gradually increased since then. The majority of examined studies were cross-sectional designs and conducted at the elite level in European and Asian countries. Most studies did not use mixed methods and did not specify the age of the subjects. Psychological research applied to futsal focused on athletes, non-athletes and several psychological factors. Critical and innovative reflections were made to highlight research gaps and present suggestions for further research.

Key words

  • futsal study
  • research design
  • data collection
  • sample characteristics
Open Access

Case Study of Mental Skills Training for a Taekwondo Olympian

Published Online: 13 Apr 2016
Page range: 235 - 245

Abstract

Abstract

The purpose of this study was to identify the effect of systematic mental skills training (MST) for a taekwondo gold medallist. Based on MST of other sports, this programme was designed for a single subject who competed in the Olympics. The Korean test of performance strategies, Sport Attributional Style in Korean Athletes, and a few sessions of interviews were applied to investigate the effect of MST. The pre and post-test mean scores of both the Korean test of performance strategies and Sport Attributional Style in Korean Athletes were compared. Interviews recorded the athlete’s psychological characteristics. Excluding the ‘activation’ variable, all of the psychological skills, e.g. self-talk (4.25–5), emotional control (3.75–4.5), automaticity (3.75–4.25), goal setting (4.5–5), imagery (4.25–5), negative thinking (3.25–4.75), anxiety management (4.5–5), and physical and mental condition (4.5–5) improved. MST is believed to have helped the athlete succeed.

Key words

  • martial arts
  • combat
  • psychology
Open Access

Coaches’ Preferences for Continuing Coaching Education in South Africa

Published Online: 13 Apr 2016
Page range: 229 - 234

Abstract

Abstract

The purpose of this study was to examine coaches’ preferences for continuing coaching education. The sample consisted of 122 male and 102 female coaches from the Gauteng Province of South Africa who were purposively recruited to participate in this study. The results of this study showed that the coaches wanted to learn more about motivational techniques, advanced instructional drills, advanced first aid, goal setting, character building and conditioning drills. The results further indicated that sport coaches would be more likely to continue their coaching education if they had a desire to coach at a high level, if topics were relevant and if courses were in line with league requirements and were available online. The practical implications of the findings for the development of coaching education programmes in South Africa were discussed.

Key words

  • coaching
  • education
  • preferences
  • certification
Open Access

The El Dorado of Handball? Foreign Female Players Stay, while Domestic Players Return from Abroad

Published Online: 13 Apr 2016
Page range: 219 - 227

Abstract

Abstract

The main purpose of this research was to study the characteristics of migration in European women’s handball based on the Slovenian example and to find the differences between the foreigners coming to Slovenia and the Slovenians transferring to foreign clubs. The research was based on 16 open face-to-face semi-structured interviews (8 Slovenians (age 29.5 ± 6.2 years) and 8 foreigners (age 35.5 ± 8.7 years)). We found out that the most powerful factor in foreigners was the financial one, while within Slovenian players it was their personal desire for progression within their sport, the club’s reputation and poor conditions in their previous club. The results confirm that when making a decision on transfer, all players had the support of family and friends, while the clubs of foreign players were not as supportive. Most interviewees considered their careers successful and did not regret going abroad. The research indicates that the largest differences discovered between Slovenians and foreigners were that foreign female players chose to stay in the new country (Slovenia), while domestic players returned home after few years playing abroad. In conclusion, the results show that in top-level handball there are important differences between migration models which are based on nationality and also that the migration models change throughout time, which is largely connected with the socioeconomic events in the country of origin or transfer.

Key words

  • migration
  • characteristics
  • women
  • top-level handball
Open Access

The Activity Profile of Young Tennis Athletes Playing on Clay and Hard Courts: Preliminary Data

Published Online: 13 Apr 2016
Page range: 211 - 218

Abstract

Abstract

The aim of this study was to compare the kinematic characteristics of tennis matches between red clay and hard courts in young tennis players. Eight young tennis players performed two tennis matches on different court surfaces. The match activities were monitored using GPS units. The distance covered in different velocity ranges and the number of accelerations were analyzed. The paired t test and inference based on magnitudes were used to compare the match physical performance between groups. The total distance (24% of difference), high-intensity running distance (15 - 18 km/h) (30% of difference), the number of high-intensity activities (44% of difference), the body load (1% of difference), and accelerations >1.5 g (1.5-2 g and >2 g 7.8 and 8.1 % of difference, respectively) were significantly greater in clay court than hard court matches (p < 0.05). Matches played on the red clay court required players to cover more total and high-intensity running distances and engage in more high-intensity activities than the matches played on the hard court. Finally, on the clay court the body load and the number of accelerations performed (>1.5 g) were possibly higher than on the hard court.

Key words

  • kinematic analysis
  • GPS
  • racquet sports
  • accelerations
Open Access

Muscle Strength and Speed Performance in Youth Soccer Players

Published Online: 13 Apr 2016
Page range: 203 - 210

Abstract

Abstract

This study aimed to examine the relationship between maximum leg extension strength and sprinting performance in youth elite male soccer players. Sixty-three youth players (12.5 ± 1.3 years) performed 5 m, flying 15 m and 20 m sprint tests and a zigzag agility test on a grass field using timing gates. Two days later, subjects performed a one-repetition maximum leg extension test (79.3 ± 26.9 kg). Weak to strong correlations were found between leg extension strength and the time to perform 5 m (r = -0.39, p = 0.001), flying 15 m (r = -0.72, p < 0.001) and 20 m (r = -0.67, p < 0.001) sprints; between body mass and 5 m (r = -0.43, p < 0.001), flying 15 m (r = -0.75, p < 0.001), 20 m (r = -0.65, p < 0.001) sprints and agility (r =-0.29, p < 0.001); and between height and 5 m (r = -0.33, p < 0.01) and flying 15 m (r = -0.74, p < 0.001) sprints. Our results show that leg muscle strength and anthropometric variables strongly correlate with sprinting ability. This suggests that anthropometric characteristics should be considered to compare among youth players, and that youth players should undergo strength training to improve running speed.

Key words

  • sprint
  • maturation
  • strength training
  • soccer
  • youth players
  • development
Open Access

The Impact of a Good Season Start on Team Performance in Elite Handball

Published Online: 13 Apr 2016
Page range: 195 - 202

Abstract

Abstract

The aim of the current study was (i) to identify how important was a good season start in relation to elite handball teams’ performance, and (ii) to examine if this impact was related to the clubs’ financial budget. The match performances and annual budgets of all teams were collected from the Spanish Professional Handball League during ten seasons. The dependent variable was the difference between the ranking of each team in accordance to the annual budget and the ranking of each team at the end of the season. A k-means cluster analysis classified the clubs according to their budget as High Range Budget Clubs (HRBC), Upper-Mid Range Budget Clubs (UMRBC), Lower-Mid Range Budget Clubs (LMRBC) and Low Range Budget Clubs (LRBC). Data were examined through linear regression models. Overall, the results suggested that the better the team performance at the beginning of the season, the better the ranking at the end of the season. Each position in the ranking above expected in accordance to the budget of the teams in Rounds 3, 4 or 5 improved by 0.47, 0.50 or 0.49, respectively, in the ranking at the end of the season (p<0.05). However, the impact of the effect depended on the clubs’ annual budget. For UMRBC, LMRBC and LRBC a good start to the season had a positive effect on the final outcome (p<0.05). Nevertheless, for HRBC, a good or a bad start of the season did not explain their final position. These variables can be used to develop accurate models to estimate final rankings. UMRBC, LMRBC and LRBC can benefit from fine-tuning preseason planning in order to accelerate the acquisition of optimal performances.

Key words

  • handball
  • financial capacity
  • team performance
  • initial results
Open Access

Indirect Methods of Assessing Maximal Oxygen Uptake in Rowers: Practical Implications for Evaluating Physical Fitness in a Training Cycle

Published Online: 13 Apr 2016
Page range: 187 - 194

Abstract

Abstract

The aim of the study was to evaluate the usefulness of indirect methods of assessment of VO2max for estimation of physical capacity of trained male and female rowers during a training cycle. A group of 8 female and 14 male rowers performed the maximal intensity test simulating the regatta distance (a 2 km test) and a submaximal incremental exercise test on a rowing ergometer. The suitability of the indirect methods of predicting VO2max during the training cycle was evaluated by performing the tests twice: in females at an interval of five months and in males at an interval of seven months. To indirectly estimate VO2max, regression formulas obtained for the linear relationship between the examined effort indices were utilized based on 1) mean power obtained in the 2 km test, and 2) submaximal exercises after the estimation of PWC170. Although the suitability of the two indirect methods of assessment of VO2max was statisticaly confirmed, their usefulness for estimation of changes in physical fitness of trained rowers during the training cycle was rather low. Such an opinion stems from the fact that the total error of these methods (range between 4.2-7.7% in female and 5.1-7.4% in male rowers) was higher than the real differences in VO2max values determined in direct measurements (between the first and the second examination maximal oxygen uptake rose by 3.0% in female rowers and decreased by 4.3% in male rowers).

Key words

  • rowing ergometer
  • indirect methods
  • VO2max
  • training cycle
Open Access

Acute Effect of Different Combined Stretching Methods on Acceleration and Speed in Soccer Players

Published Online: 13 Apr 2016
Page range: 179 - 186

Abstract

Abstract

The purpose of this study was to investigate the acute effect of different stretching methods, during a warm-up, on the acceleration and speed of soccer players. The acceleration performance of 20 collegiate soccer players (body height: 177.25 ± 5.31 cm; body mass: 65.10 ± 5.62 kg; age: 16.85 ± 0.87 years; BMI: 20.70 ± 5.54; experience: 8.46 ± 1.49 years) was evaluated after different warm-up procedures, using 10 and 20 m tests. Subjects performed five types of a warm-up: static, dynamic, combined static + dynamic, combined dynamic + static, and no-stretching. Subjects were divided into five groups. Each group performed five different warm-up protocols in five non-consecutive days. The warm-up protocol used for each group was randomly assigned. The protocols consisted of 4 min jogging, a 1 min stretching program (except for the no-stretching protocol), and 2 min rest periods, followed by the 10 and 20 m sprint test, on the same day. The current findings showed significant differences in the 10 and 20 m tests after dynamic stretching compared with static, combined, and no-stretching protocols. There were also significant differences between the combined stretching compared with static and no-stretching protocols. We concluded that soccer players performed better with respect to acceleration and speed, after dynamic and combined stretching, as they were able to produce more force for a faster execution.

Key words

  • combined stretching
  • soccer
  • acceleration
  • speed
  • warm-up
Open Access

Investigating the Effects of Typical Rowing Strength Training Practices on Strength and Power Development and 2,000 m Rowing Performance

Published Online: 13 Apr 2016
Page range: 167 - 177

Abstract

Abstract

This study aimed to determine the effects of a short-term, strength training intervention, typically undertaken by club-standard rowers, on 2,000 m rowing performance and strength and power development. Twenty-eight male rowers were randomly assigned to intervention or control groups. All participants performed baseline testing involving assessments of muscle soreness, creatine kinase activity (CK), maximal voluntary contraction (leg-extensors) (MVC), static-squat jumps (SSJ), counter-movement jumps (CMJ), maximal rowing power strokes (PS) and a 2,000 m rowing ergometer time-trial (2,000 m) with accompanying respiratory-exchange and electromyography (EMG) analysis. Intervention group participants subsequently performed three identical strength training (ST) sessions, in the space of five days, repeating all assessments 24 h following the final ST. The control group completed the same testing procedure but with no ST. Following ST, the intervention group experienced significant elevations in soreness and CK activity, and decrements in MVC, SSJ, CMJ and PS (p < 0.01). However, 2,000 m rowing performance, pacing strategy and gas exchange were unchanged across trials in either condition. Following ST, significant increases occurred for EMG (p < 0.05), and there were non-significant trends for decreased blood lactate and anaerobic energy liberation (p = 0.063 – 0.086). In summary, club-standard rowers, following an intensive period of strength training, maintained their 2,000 m rowing performance despite suffering symptoms of muscle damage and disruption to muscle function. This disruption likely reflected the presence of acute residual fatigue, potentially in type II muscle fibres as strength and power development were affected.

Key words

  • recovery
  • muscle function
  • muscle damage
  • resistance training
  • endurance performance
Open Access

The Relationship Between the Lower-Body Muscular Profile and Swimming Start Performance

Published Online: 13 Apr 2016
Page range: 157 - 165

Abstract

Abstract

This study aimed to examine the correlation of different dry land strength and power tests with swimming start performance. Twenty international level female swimmers (age 15.3 ± 1.6 years, FINA point score 709.6 ± 71.1) performed the track freestyle start. Additionally, dry land tests were conducted: a) squat (SJ) and countermovement jumps (CMJ), b) squat jumps with additional resistance equivalent to 25, 50, 75 and 100% of swimmers’ body weight [BW]), and c) leg extension and leg flexion maximal voluntary isometric contractions. Correlations between dry land tests and start times at 5, 10 and 15 m were quantified through Pearson’s linear correlation coefficients (r). The peak bar velocity reached during the jumps with additional resistance was the variable most correlated to swimming start performance (r = -0.57 to -0.66 at 25%BW; r = -0.57 to -0.72 at 50%BW; r = -0.59 to -0.68 at 75%BW; r = -0.50 to - 0.64 at 100%BW). A few significant correlations between the parameters of the SJ and the CMJ with times of 5 and 10 m were found, and none with the isometric variables. The peak velocity reached during jumps with external loads relative to BW was found a good indicator of swimming start performance.

Key words

  • swim start
  • freestyle swimming
  • dry land test
  • jumps with additional resistance
  • isometric test
Open Access

Preseason Strategies of Italian First League Soccer Clubs in Relation to their Championship Ranking: A Five-Year Analysis

Published Online: 13 Apr 2016
Page range: 145 - 155

Abstract

Abstract

This study is focused on the strategies adopted by Italian ‘Serie A’ soccer clubs during the non-competitive period. Thus, duration (i.e., number of days) of the specific non-competitive periods (i.e., off- plus pre-season, off-season, pre-season, summer camp), the number of games (i.e., friendly, official and polled games) and days between games (i.e., ≤ 3, 4-5, or ≥ 6 days between two consecutive games) of the entire non-competitive period were recorded and compared by clubs participating in the European Championships (EU), only ‘Serie A’ (A) and promoted from ‘Serie B’ (B) during five and single seasons (i.e., 2009/10-2013/14). Due to the short B off-season duration (2009/10-2013/14, 2010/11, 2011/12, 2012/13, 2013/14, p≤.001), effects between clubs emerged also for the off- plus preseason (2009/10-2013/14, EU vs A, p≤.01, EU vs B, p≤.01, A vs B, p≤.001; 2011/12, 2012/13, 2013/14, p≤.001). Nevertheless, no difference between clubs resulted for the pre-season. Reduced duration of summer camps was reported by the EU (i.e., 2009/10-2013/14, 2009/10, 2013/14, p≤.001). A higher number of official games were played by EU than A (i.e., 2009/10-2013/14, p≤.001; 2010/11, p≤.01). No effect emerged for the days between games. Therefore, despite the longer ‘Serie B’ schedule and EU preliminary UEFA games that determined the off-season restriction, clubs demonstrated the tendency to guarantee satisfactory pre-season duration.

Key words

  • team sports periodization
  • Italian soccer first league
  • summer training camp
Open Access

Lower Limb Neuromuscular Asymmetry in Volleyball and Basketball Players

Published Online: 13 Apr 2016
Page range: 135 - 143

Abstract

Abstract

The primary objective of the present study was to evaluate the agreement between the dominant leg (DL) (determined subjectively) and the stronger leg (SL) (determined via a functional test) in a group of basketball and volleyball players. The secondary objective was to calculate lower limb neuromuscular asymmetry when comparing the DL vs the non-dominant leg (NDL) and the SL vs the weaker (WL) leg in the whole group and when differentiating by sex. Seventy-nine male and female volleyball and basketball players (age: 23.7 ± 4.5 years) performed three single-leg vertical countermovement jumps (SLVCJ) on a contact mat. Vertical jump height and an inter-limb asymmetry index (ASI) were determined. Only 32 (40%) of the subjects had a concordance between the perception of their dominant leg and the limb reaching the highest jump height. Using the DL as the discriminating variable, significant (p<0.05) inter-limb differences were found in the total group of players. When comparing between sexes, significant differences (p<0.05) arose in the female group only. With regard to the WL vs. the SL, significant (p<0.05) differences were noted in the whole group and when stratified into males and females. The mean ASI ranged from 9.31% (males) to 12.84% (females) and from 10.49% (males) to 14.26% (females), when comparing the DL vs. the NDL and the SL vs. the WL, respectively. Subjective expression of leg dominance cannot be used as a predictor of limb jump performance. Vertical jump asymmetry of 10-15% exists and this can be considered as a reference value for male and female basketball and volleyball players.

Key words

  • power
  • unilateral
  • imbalances
  • alpinist expedition
  • team sport games
Open Access

The Influence of High-Altitude Acclimatization on Ventilatory and Blood Oxygen Saturation Responses During Normoxic and Hypoxic Testing

Published Online: 13 Apr 2016
Page range: 125 - 133

Abstract

Abstract

We investigated how acclimatization effects achieved during a high-altitude alpinist expedition influence endurance performance, ventilation (V˙E${\dot V_E}$) and blood oxygen saturation (SaO2) in normoxic (NOR) and hypoxic conditions (HYP). An incremental testing protocol on a cycle ergometer was used to determine the power output corresponding to the Lactate (PLT) and Ventilatory Threshold (PVT) in NOR and HYP (FiO2=0.13) as indirect characteristics of endurance performance in both conditions. Furthermore, changes in V˙E${\dot V_E}$, SaO2, blood pH and Pco2 were measured at a similar absolute exercise intensity of 180 W in NOR and HYP conditions. Seven experienced alpinists (mean ± SD: age: 50 ± 6 yrs; body mass: 76 ± 5 kg; body height: 175 ± 8 cm) volunteered to participate in this study after they had reached the summit of Gasherbrum II and Ama Dablam. They had therefore experienced the limitations of their acclimatization. Individual differences of PLT between values reached after and before the expedition (∆PLT) correlated (r = 0.98, p = 0.01) with differences of SaO2 (∆SaO2) in HYP, and differences of PVT (∆PVT) correlated (r = -0.83, p = 0.02) with differences of V˙E(ΔV˙E)${\dot V_E}\left( {\Delta {{\dot V}_E}} \right)$ in HYP. The results suggest that the acclimatization may not have an equivocal and simple influence on the performance in hypoxia: enhanced blood oxygen saturation may be accompanied by increased endurance only, when the increase exceeded 2-3%, but enhanced ventilation, when increased more than 10 l/min in HYP, could detrimentally influence endurance.

Key words

  • hypoxia
  • normoxia
  • acclimatization
  • alpinist expedition
  • endurance
Open Access

Influence of Physiological Loading on the Lumbar Spine of National Level Athletes in Different Sports

Published Online: 13 Apr 2016
Page range: 115 - 123

Abstract

Abstract

The lumbar spine is subjected to considerable stress during many athletic efforts. The purpose of this study was to assess the effects of physiological loading on the lumbar spine in national male players of different games, which may be predictive of the future development of low back pain and injury symptoms. Thirty-four national players (12 cricket players, 12 field hockey players, and 10 basketball players) underwent magnetic resonance imaging, and selected geometric variables including intervertebral disc angles, the Farfan ratio, the lumbar body index, the compression deformity ratio, the biconcave deformity ratio and the anterior wedge deformity ratio were measured using KINOVEA-0.8.15 software and syngo fast view software and calculated using specific formulas. The results indicated a significant difference in the intervertebral disc angle between the three groups at the L2/3, L3/4 and L4/5 levels. In relation to the lumbar vertebral body shape and size, significant differences were found in the lumbar index at the L2 level, in the biconcave deformity at the L1 and L2 levels and in relation to the anterior wedge deformity at L2 between the three selected groups. Our data suggest that the different physiological loadings in the selected sports play an important role in the development of degenerative changes of the lumbar spine, which may be considered a risk factor for future injury and/or low back pain in each specific sport because of the unique demands of each discipline.

Key words

  • degenerative changes
  • magnetic resonance imaging
  • basketball
  • cricket
  • field hockey
Open Access

Application of A Physiological Strain Index in Evaluating Responses to Exercise Stress – A Comparison Between Endurance and High Intensity Intermittent Trained Athletes

Published Online: 13 Apr 2016
Page range: 103 - 114

Abstract

Abstract

The study evaluated differences in response to exercise stress between endurance and high-intensity intermittent trained athletes in a thermoneutral environment using a physiological strain index (PSI). Thirty-two subjects participated in a running exercise under normal (23°C, 50% RH) conditions. The group included nine endurance trained athletes (middle-distance runners - MD), twelve high-intensity intermittent trained athletes (soccer players - HIIT) and eleven students who constituted a control group. The exercise started at a speed of 4 km·h–1 which was increased every 3 min by 2 km·h–1 to volitional exhaustion. The heart rate was recorded with a heart rate monitor and aural canal temperature was measured using an aural canal temperature probe. The physiological strain index (PSI) and the contribution of the circulatory and thermal components to the overall physiological strain were calculated from the heart rate and aural canal temperature. The physiological strain index differed between the study and control participants, but not between the MD and HIIT groups. The physiological strain in response to exercise stress in a thermoneutral environment was mainly determined based on the circulatory strain (MD group - 73%, HIIT group – 70%). The contribution of the circulatory and thermal components to the physiological strain did not differ significantly between the trained groups (MD and HIIT) despite important differences in morphological characteristics and training-induced systemic cardiovascular and thermoregulatory adaptations.

Key words

  • physiological strain
  • exercise
  • adaptation
  • thermoneutral conditions
  • athletes
Open Access

Differences in Physiological Responses to Interval Training in Cyclists With and Without Interval Training Experience

Published Online: 13 Apr 2016
Page range: 93 - 101

Abstract

Abstract

The aim of this study was to determine differences in glycolytic metabolite concentrations and work output in response to an all-out interval training session in 23 cyclists with at least 2 years of interval training experience (E) and those inexperienced (IE) in this form of training. The intervention involved subsequent sets of maximal intensity exercise on a cycle ergometer. Each set comprised four 30 s repetitions interspersed with 90 s recovery periods; sets were repeated when blood pH returned to 7.3. Measurements of post-exercise hydrogen (H+) and lactate ion (LA-) concentrations and work output were taken. The experienced cyclists performed significantly more sets of maximal efforts than the inexperienced athletes (5.8 ± 1.2 vs. 4.3 ± 0.9 sets, respectively). Work output decreased in each subsequent set in the IE group and only in the last set in the E group. Distribution of power output changed only in the E group; power decreased in the initial repetitions of set only to increase in the final repetitions. H+ concentration decreased in the third, penultimate, and last sets in the E group and in each subsequent set in the IE group. LA- decreased in the last set in both groups. In conclusion, the experienced cyclists were able to repeatedly induce elevated levels of lactic acidosis. Power output distribution changed with decreased acid–base imbalance. In this way, this group could compensate for a decreased anaerobic metabolism. The above factors allowed cyclists experienced in interval training to perform more sets of maximal exercise without a decrease in power output compared with inexperienced cyclists.

Key words

  • maximal glycolytic exercise
  • lactic acidosis
  • training load
Open Access

Within-Session Stability of Short-Term Heart Rate Variability Measurement

Published Online: 13 Apr 2016
Page range: 85 - 92

Abstract

Abstract

The primary aim of this study was to assess the retest stability of the short-term heart rate variability (HRV) measurement performed within one session and without the use of any intervention. Additionally, a precise investigation of the possible impact of intrinsic biological variation on HRV reliability was also performed. First, a single test-retest HRV measurement was conducted with 20-30 min apart from one another. Second, the HRV measurement was repeated in ten non-interrupted consecutive intervals. The lowest typical error (CV = 21.1%) was found for the square root of the mean squared differences of successive RR intervals (rMSSD) and the highest for the low frequency power (PLF) (CV = 93.9%). The standardized changes in the mean were trivial to small. The correlation analysis revealed the highest level for ln rMSSD (ICC = 0.87), while ln PLF represented the worst case (ICC = 0.59). The reliability indices for ln rMSSD in 10 consecutive intervals improved (CV = 9.9%; trivial standardized changes in the mean; ICC = 0.96). In conclusion, major differences were found in the reliability level between the HRV indices. The rMSSD demonstrated the highest reliability level. No substantial influence of intrinsic biological variation on the HRV reliability was observed.

Key words

  • heart rate variability
  • reliability
  • typical error
  • autonomic nervous system
Open Access

Prevalence of Dehydration Before Training Sessions, Friendly and Official Matches in Elite Female Soccer Players

Published Online: 13 Apr 2016
Page range: 79 - 84

Abstract

Abstract

This study aimed to evaluate and compare the hydration states prior to different sporting events (training sessions, friendly and official matches) in elite female soccer players and relate that to the importance that the player attached to the hydration state as a determinant of sports performance. The hydration state of 17 female elite soccer players (age: 21.5 ± 3 years; body mass: 62 ± 6 kg; body height: 165 ± 9 cm) was determined by measuring their urine specific gravity (USG) prior to three different sports events: training sessions (PT), friendly (PF) and official (PO) matches. The importance that each player attached to the hydration state as a determinant of sports performance was evaluated through a simple questionnaire. An average of 47.05% of the soccer players were severely dehydrated (USG > 1.030), 33.33% were significantly dehydrated (USG > 1.020), 17.64% were mildly dehydrated (USG > 1.010) and 1.96% were euhydrated (USG < 1.010). The average USG was 1.027 ± 0.007 (PT = 1.029 ± 0.009; PF = 1.023 ± 0.010 and PO = 1.030 ± 0.006). Differences were found between urine specific gravity prior to a friendly and an official match (p = 0.03). No relationship was found between urine specific gravity and the importance each player attached to the hydration state as a determinant of sports performance. The results show that dehydration is the most prevalent hydration state of elite soccer players before training sessions, friendly and official matches. Players were most dehydrated prior to official matches, which was unlinked to the players’ perceived importance of hydration for sports performance.

Key words

  • dehydration
  • soccer
  • hydration
  • female player
Open Access

25(OH)D3 Levels Relative to Muscle Strength and Maximum Oxygen Uptake in Athletes

Published Online: 13 Apr 2016
Page range: 71 - 77

Abstract

Abstract

Vitamin D is mainly known for its effects on the bone and calcium metabolism. The discovery of Vitamin D receptors in many extraskeletal cells suggests that it may also play a significant role in other organs and systems. The aim of our study was to assess the relationship between 25(OH)D3 levels, lower limb isokinetic strength and maximum oxygen uptake in well-trained professional football players. We enrolled 43 Polish premier league soccer players. The mean age was 22.7±5.3 years. Our study showed decreased serum 25(OH)D3 levels in 74.4% of the professional players. The results also demonstrated a lack of statistically significant correlation between 25(OH)D3 levels and lower limb muscle strength with the exception of peak torque of the left knee extensors at an angular velocity of 150°/s (r=0.41). No significant correlations were found between hand grip strength and maximum oxygen uptake. Based on our study we concluded that in well-trained professional soccer players, there was no correlation between serum levels of 25(OH)D3 and muscle strength or maximum oxygen uptake.

Key words

  • vitamin D
  • muscle strength
  • VO
  • athletes
Open Access

Two-Man Bobsled Push Start Analysis

Published Online: 13 Apr 2016
Page range: 63 - 70

Abstract

Abstract

The importance of push start times on bobsled performance was evidenced by some studies, but at this moment there is no article to the authors’ knowledge that describes the bobsled push start. Thus, the objectives of this study were to describe the two-man bobsled push start, analyze the differences between teams, and estimate the most important variable analyzed. We hypothesized that the pilot and brakeman athletes’ movement patterns during a bobsled pushing start can be described. The images used in this study were obtained during the men’s two-man XIV World Championship of Bobsled (2004). Fifteen best teams participating in the championship were recorded, and four start runs for each team were analyzed. The videos were captured by two digital video cameras. The pilot athletes were analyzed during the moment that they touched the lateral push bar of the sled, and the brakemen were analyzed during the first take-off and first landing. The teams were pooled in three groups of five teams using the final ranking of pushing time. We concluded that there was a distinct pattern movement for pilots and brakemen. The initial position of the majority of the pilots was localized slightly behind the bar. After touching the lateral bar, the pilots remained in a semi-squat position, pushing the sled forward in a pattern of marching movement. All brakemen used the board attached to the track as a support for both feet at the start. The brakeman gave the greatest contribution to break the inertia of the sled. There was no significant difference of movement between the three groups analyzed for the pilot and the brakeman.

Key words

  • bobsleigh
  • winter sport
  • biomechanics
Open Access

Three-Dimensional Motion Analysis of Lumbopelvic Rhythm During Trunk Extension

Published Online: 13 Apr 2016
Page range: 53 - 62

Abstract

Abstract

Hip–spine coordination, known as the lumbopelvic rhythm, can be expressed as the lumbar–hip ratio. The lumbopelvic rhythm and lumbar–hip ratio can be used to assess lower limb function. We clarified the lumbopelvic rhythm and lumbar–hip ratio during trunk extension. We established a novel set of marker positions for three-dimensional motion analysis to assess the lumbar spinal angle. The original markers were placed on both paravertebral muscle groups at the 11th thoracic spinous process level, the 10th and 12th thoracic spinous processes, and the pelvis. We measured angle data during trunk extension using three-dimensional motion analysis, and the data for eight healthy male subjects were categorized into backward and forward phases. The lumbar–hip ratio increased significantly from 1.2 to 1.9 (mean, 1.6) in the backward phase, indicating considerable movement of the lumbar spine compared with hip movement in the latter phase. In the forward phase, the ratio decreased significantly from 1.9 to 0.5 (mean, 1.5). After completion of 80% of the forward phase, the lumbar–hip ratio decreased to <1.0. The lumbopelvic rhythm for trunk extension was better expressed by a cubic or quadratic function than a linear function. According to a linear function, when the hip extends by 1°, lumbar spine extends by 1.9°. Therefore, lumbar spinal movement was greater than hip movement in the sagittal plane. The implication of the curved line would indicate lumbar extension instead of the limitation of hip extension.

Key words

  • lumbopelvic rhythm
  • lumbar–hip ratio
  • lumbar spine angle
  • hip angle
  • trunk extension
Open Access

Balance Maintenance in the Upright Body Position: Analysis of Autocorrelation

Published Online: 13 Apr 2016
Page range: 45 - 52

Abstract

Abstract

The present research aimed to analyze values of the autocorrelation function measured for different time values of ground reaction forces during stable upright standing. It was hypothesized that if recording of force in time depended on the quality and way of regulating force by the central nervous system (as a regulator), then the application of autocorrelation for time series in the analysis of force changes in time function would allow to determine regulator properties and its functioning. The study was performed on 82 subjects (students, athletes, senior and junior soccer players and subjects who suffered from lower limb injuries). The research was conducted with the use of two Kistler force plates and was based on measurements of ground reaction forces taken during a 15 s period of standing upright while relaxed. The results of the autocorrelation function were statistically analyzed. The research revealed a significant correlation between a derivative extreme and velocity of reaching the extreme by the autocorrelation function, described as gradient strength. Low correlation values (all statistically significant) were observed between time of the autocorrelation curve passing through 0 axis and time of reaching the first peak by the said function. Parameters computed on the basis of the autocorrelation function are a reliable means to evaluate the process of flow of stimuli in the nervous system. Significant correlations observed between the parameters of the autocorrelation function indicate that individual parameters provide similar properties of the central nervous system.

Key words

  • lateralization
  • lower limbs
  • force
  • balance
  • autocorrelation
Open Access

Maximum Velocities in Flexion and Extension Actions for Sport

Published Online: 13 Apr 2016
Page range: 37 - 44

Abstract

Abstract

Speed of movement is fundamental to the outcome of many human actions. A variety of techniques can be implemented in order to maximise movement speed depending on the goal of the movement, constraints, and the time available. Knowing maximum movement velocities is therefore useful for developing movement strategies but also as input into muscle models. The aim of this study was to determine maximum flexion and extension velocities about the major joints in upper and lower limbs. Seven university to international level male competitors performed flexion/extension at each of the major joints in the upper and lower limbs under three conditions: isolated; isolated with a countermovement; involvement of proximal segments. 500 Hz planar high speed video was used to calculate velocities. The highest angular velocities in the upper and lower limb were 50.0 rad·s-1 and 28.4 rad·s-1, at the wrist and knee, respectively. As was true for most joints, these were achieved with the involvement of proximal segments, however, ANOVA analysis showed few significant differences (p<0.05) between conditions. Different segment masses, structures and locations produced differing results, in the upper and lower limbs, highlighting the requirement of segment specific strategies for maximal movements.

Key words

  • maximal
  • angular
  • velocity
  • movement pattern
Open Access

Spatiotemporal Parameters are not Substantially Influenced by Load Carriage or Inclination During Treadmill and Overground Walking

Published Online: 13 Apr 2016
Page range: 27 - 35

Abstract

Abstract

Influences of load carriage and inclination on spatiotemporal parameters were examined during treadmill and overground walking. Ten soldiers walked on a treadmill and overground with three load conditions (00 kg, 20 kg, 40 kg) during level, uphill (6% grade) and downhill (-6% grade) inclinations at self-selected speed, which was constant across conditions. Mean values and standard deviations for double support percentage, stride length and a step rate were compared across conditions. Double support percentage increased with load and inclination change from uphill to level walking, with a 0.4% stance greater increase at the 20 kg condition compared to 00 kg. As inclination changed from uphill to downhill, the step rate increased more overground (4.3 ± 3.5 steps/min) than during treadmill walking (1.7 ± 2.3 steps/min). For the 40 kg condition, the standard deviations were larger than the 00 kg condition for both the step rate and double support percentage. There was no change between modes for step rate standard deviation. For overground compared to treadmill walking, standard deviation for stride length and double support percentage increased and decreased, respectively. Changes in the load of up to 40 kg, inclination of 6% grade away from the level (i.e., uphill or downhill) and mode (treadmill and overground) produced small, yet statistically significant changes in spatiotemporal parameters. Variability, as assessed by standard deviation, was not systematically lower during treadmill walking compared to overground walking. Due to the small magnitude of changes, treadmill walking appears to replicate the spatiotemporal parameters of overground walking.

Key words

  • gait
  • uphill
  • downhill
  • external load
Open Access

Explosive Strength of the Knee Extensors: The Influence of Criterion Trial Detection Methodology on Measurement Reproducibility

Published Online: 13 Apr 2016
Page range: 15 - 25

Abstract

Abstract

The present study was conducted to assess test-retest reproducibility of explosive strength measurements during single-joint isometric knee extension using the IsoMed 2000 dynamometer. Thirty-one physically active male subjects (mean age: 23.7 years) were measured on two occasions separated by 48–72 h. The intraclass correlation coefficient (ICC 2,1) and the coefficient of variation (CV) were calculated for (i) maximum torque (MVC), (ii) the peak rate of torque development (RTDpeak) as well as for (iii) the average rate of torque development (RTD) and the impulse taken at several predefined time intervals (0–30 to 0–300 ms); thereby explosive strength variables were derived in two conceptually different versions: on the one hand from the MVC-trial (version I), on the other hand from the trial showing the RTDpeak (version II). High ICC-values (0.80–0.99) and acceptable CV-values (1.9–8.7%) could be found for MVC as well as for the RTD and the impulse taken at time intervals of ≥100 ms, regardless of whether version I or II was used. In contrast, measurements of the RTDpeak as well as the RTD and the impulse taken during the very early contraction phase (i.e. RTD/impulse0–30ms and RTD/impulse0–50ms) showed clearly weaker reproducibility results (ICC: 0.53–0.84; CV: 7.3–16.4%) and gave rise to considerable doubts as to clinical usefulness, especially when derived using version I. However, if there is a need to measure explosive strength for earlier time intervals in practice, it is, in view of stronger reproducibility results, recommended to concentrate on measures derived from version II, which is based on the RTDpeak-trial.

Key words

  • explosive torque production
  • rate of torque development
  • impulse
  • knee extension
  • IsoMed 2000
  • test-retest reproducibility
Open Access

Transferability between Isolated Joint Torques and a Maximum Polyarticular Task: A Preliminary Study

Published Online: 13 Apr 2016
Page range: 5 - 14

Abstract

Abstract

The aims of this study were to determine if isolated maximum joint torques and joint torques during a maximum polyarticular task (i.e. cycling at maximum power) are correlated despite joint angle and velocity discrepancies, and to assess if an isolated joint-specific torque production capability at slow angular velocity is related to cycling power. Nine cyclists completed two different evaluations of their lower limb maximum joint torques. Maximum Isolated Torques were assessed on isolated joint movements using an isokinetic ergometer and Maximum Pedalling Torques were calculated at the ankle, knee and hip for flexion and extension by inverse dynamics during cycling at maximum power. A correlation analysis was made between Maximum Isolated Torques and respective Maximum Pedalling Torques [3 joints x (flexion + extension)], showing no significant relationship. Only one significant relationship was found between cycling maximum power and knee extension Maximum Isolated Torque (r=0.68, p<0.05). Lack of correlations between isolated joint torques measured at slow angular velocity and the same joint torques involved in a polyarticular task shows that transfers between both are not direct due to differences in joint angular velocities and in mono-articular versus poly articular joint torque production capabilities. However, this study confirms that maximum power in cycling is correlated with slow angular velocity mono-articular maximum knee extension torque.

Key words

  • cycling
  • isokinetic ergometer
  • inverse dynamics
  • force-velocity test

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