Search

© 2015 Human Kinetics, Inc. Purpose: To examine the training periodization of an elite Australian Football team during different phases of the season. Methods: Training-load data were collected during 22 wk of preseason and 23 wk of in-season training. Training load was measured using the session rating of perceived exertion (session-RPE) for all training sessions and matches from 44 professional Australian Football players from the same team. Training intensity was divided into 3 zones based on session-RPE (low, <4; moderate, >4 AU and <7 AU; and high, >7 AU). Training load and intensity were analyzed according to the type of training session completed. Results: Higher training load and session duration were undertaken for all types of training sessions during the preseason than in-season (P < .05), with the exception of "other" training (ie, re/prehabilitation training, cross-training, and recovery activities). Training load and intensity were higher during the preseason, with the exception of games, where greater load and intensity were observed during the in-season. The overall distribution of training intensity was similar between phases with the majority of training performed at moderate or high intensity. Conclusions: The current findings may allow coaches and scientists to better understand the characteristics of Australian Football periodization, which in turn may aid in developing optimal training programs. The results also indicate that a polarized training-intensity distribution that has been reported in elite endurance athletes does not occur in professional Australian Football.

Exercising in the heat induces thermoregulatory and other physiological strain that can lead to impairments in endurance exercise capacity. The purpose of this consensus statement is to provide up-to-date recommendations to optimise performance during sporting activities undertaken in hot ambient conditions. The most important intervention one can adopt to reduce physiological strain and optimise performance is to heat acclimatise. Heat acclimatisation should comprise repeated exercise-heat exposures over 1-2 weeks. In addition, athletes should initiate competition and training in a euhydrated state and minimise dehydration during exercise. Following the development of commercial cooling systems (eg, cooling-vest), athletes can implement cooling strategies to facilitate heat loss or increase heat storage capacity before training or competing in the heat. Moreover, event organisers should plan for large shaded areas, along with cooling and rehydration facilities, and schedule events in accordance with minimising the health risks of athletes, especially in mass participation events and during the first hot days of the year. Following the recent examples of the 2008 Olympics and the 2014 FIFA World Cup, sport governing bodies should consider allowing additional (or longer) recovery periods between and during events, for hydration and body cooling opportunities, when competitions are held in the heat.

© 2015 Human Kinetics, Inc. This study aimed to profile the physiological characteristics of junior sprint kayak athletes (n = 21, VO2max 4.10.7 L/min, training experience 2.71.2 y) and to establish the relationship between physiological variables (VO2max, VO2 kinetics, muscleoxygen kinetics, paddling efficiency) and sprint kayak performance. VO2max, power at VO2max, power:weight ratio, paddling efficiency, VO2 at lactate threshold, and whole-body and muscle oxygen kinetics were determined on a kayak ergometer in the laboratory. Separately, on-water time trials (TT) were completed over 200 m and 1000 m. Large to nearly perfect (-.5 to-.9) inverse relationships were found between the physiological variables and on-water TT performance across both distances. Paddling efficiency and lactate threshold shared moderate to very large correlations (-.4 to-.7) with 200- and 1000-m performance. In addition, trivial to large correlations (-.11 to-.5) were observed between muscle-oxygenation parameters, muscle and whole-body oxygen kinetics, and performance. Multiple regression showed that 88% of the unadjusted variance for the 200-m TT performance was explained by VO2max, peripheral muscle deoxygenation, and maximal aerobic power (P < .001), whereas 85% of the unadjusted variance in 1000-m TT performance was explained by VO2max and deoxyhemoglobin (P < .001). The current findings show that well-trained junior sprint kayak athletes possess a high level of relative aerobic fitness and highlight the importance of the peripheral muscle metabolism for sprint kayak performance, particularly in 200-m races, where finalists and nonfinalists are separated by very small margins. Such data highlight the relative aerobic-fitness variables that can be used as benchmarks for talent-identification programs or monitoring longitudinal athlete development. However, such approaches need further investigation.

© 2014 Taylor & Francis. This study examined the changes in external outputs, including metabolic power variables, and internal response whilst considering contextual factors on physical performance variables during rugby league match play. Physical performance (total distance, high-speed running and high-power distances, average metabolic power), heart-rate (percentage heart-rate peak and training impulse), collisions (attacking and defensive) and contextual (time in attack, time in defence, time out of play) data were collected from 18 rugby league players during 38 games throughout two National Rugby League seasons. Physical variables were highest in the first 10-min period of each half (P < 0.001). Heart-rate indices peaked in the second 10-min period and were lower during second half periods (P < 0.001). Few differences existed in collisions and contextual factors across 10-min periods. Physical variables were highest during the first 5-min period compared to the final (P < 0.001). There was no difference in heart-rate response, attacking collisions or contextual factors between these periods. Following the peak 5-min period in the match, there were reductions in physical, heart-rate, defensive collisions and contextual factors (P < 0.001). The data show temporal changes in physical performance, heart-rate response and collisions during rugby league match play, although these are affected by contextual factors.

© 2015 Human Kinetics, Inc. Purpose: To describe the physical and technical demands of rugby league 9s (RL9s) match play for positional groups. Methods: Global positioning system data were collected during 4 games from 16 players from a team competing in the Auckland RL9s tournament. Players were classified into positional groups (pivots, outside backs, and forwards). Absolute and relative physical-performance data were classified as total high-speed running (HSR; >14.4 km/h), very-high-speed running (VHSR; >19.0 km/h), and sprint (>23.0 km/h) distances. Technical-performance data were obtained from a commercial statistics provider. Activity cycles were coded by an experienced video analyst. Results: Forwards (1088 m, 264 m) most likely completed less overall and high-speed distances than pivots (1529 m, 371 m) and outside backs (1328 m, 312 m). The number of sprint efforts likely varied between positions, although differences in accelerations were unclear. There were no clear differences in relative total (115.6-121.3 m/min) and HSR (27.8-29.8 m/min) intensities, but forwards likely performed less VHSR (7.7 m/min) and sprint distance (1.3 m/min) per minute than other positions (10.2-11.8 m/min, 3.7-4.8 m/min). The average activity and recovery cycle lengths were ∼50 and ∼27 s, respectively. The average longest activity cycle was ∼133 s, while the average minimum recovery time was ∼5 s. Technical involvements including tackles missed, runs, tackles received, total collisions, errors, off-loads, line breaks, and involvements differed between positions. Conclusions: Positional differences exist for both physical and technical measures, and preparation for RL9s play should incorporate these differences.

© 2015 Human Kinetics, Inc. Purpose: To describe the metabolic demands of rugby league match play for positional groups and compare match distances obtained from high-speed-running classifications with those derived from high metabolic power. Methods: Global positioning system (GPS) data were collected from 25 players from a team competing in the National Rugby League competition over 39 matches. Players were classified into positional groups (adjustables, outside backs, hit-up forwards, and wide-running forwards). The GPS devices provided instantaneous raw velocity data at 5 Hz, which were exported to a customized spreadsheet. The spreadsheet provided calculations for speed-based distances (eg, total distance; high-speed running, >14.4 km/h; and very-highspeed running, >18.1 km/h) and metabolic-power variables (eg, energy expenditure; average metabolic power; and high-power distance, >20 W/kg). Results: The data show that speed-based distances and metabolic power varied between positional groups, although this was largely related to differences in time spent on field. The distance covered at high running speed was lower than that obtained from high-power thresholds for all positional groups; however, the difference between the 2 methods was greatest for hit-up forwards and adjustables. Conclusions: Positional differences existed for all metabolic parameters, although these are at least partially related to time spent on the field. Higher-speed running may underestimate the demands of match play when compared with high-power distance-although the degree of difference between the measures varied by position. The analysis of metabolic power may complement traditional speed-based classifications and improve our understanding of the demands of rugby league match play.

© 2015 Human Kinetics, Inc. Purpose: To examine the effect of different exercise-intensity distributions within a training session on the session rating of perceived exertion (RPE) and to examine the timing of measure on the rating. Methods: Nineteen junior players (age 16 ± 1 y, height 173 ± 5 cm, body mass 64 ± 6 kg) from a Swiss soccer team were involved in the study. Percentage of heart rate maximum (%HR) and RPE (Borg CR100® ) were collected in 4 standardized training sessions (conditions). The Total Quality of Recovery scale (TQR) and a visual analogue scale (VAS) for pain of the lower limbs were used to control for the effect of pretraining fatigue. Every session consisted of three 20-min blocks of different intensities (ie, low-moderate-high) performed in a random order. RPE was collected after every block (RPE5), immediately after the session (RPE-end), and 30 min after the session (RPE30). Results: RPE5s of each block were different depending on the distribution sequence (P < .0001). RPE-end, TQR, and VAS values were not different between conditions (P = .57, P = .55, and P = .96, respectively). The %HR was significantly different between conditions (P = .008), with condition 3 higher than condition 2 (74.1 vs 70.2%, P = .02). Edwards training loads were not significantly different between conditions (P = .09). RPE30 was not different from RPE-end (P > .05). Conclusions: The current results show that coaches can design training sessions without concern about the influence of the within-session distribution of exercise intensity on session-RPE and that RPE can be collected at the end of the session or 30 min later.

© 2014 Sports Medicine Australia. Objectives: To compare the metabolic power demands between positional groups, and examine temporal changes in these parameters during Australian Football match-play. Design: Longitudinal observational study. Methods: Global positioning system data were collected from 39 Australian Football players from the same club during 19 Australian Football League competition games over two seasons. A total of 342 complete match samples were obtained for analysis. Players were categorised into one of six positional groups: tall backs, mobile backs, midfielders, tall forwards, mobile forwards and rucks. Instantaneous raw velocity data obtained from the global positioning system units was exported to a customised spreadsheet which provided estimations of both speed-based (e.g. total and high-speed running distance) and derived metabolic power and energy expenditure variables (e.g. average metabolic power, high-power distance, total energy expenditure). Results: There were significant differences between positional groups for both speed-based and metabolic power indices, with midfielders covering more total and high-speed distance, as well as greater average and overall energy expenditure compared to other positions (all p<. 0.001). There were reductions in total, high-speed, and high-power distance, as well as average metabolic power throughout the match (all p<. 0.001). Conclusions: Positional differences exist for both metabolic power and traditional running based variables. Generally, midfielders, followed by mobile forwards and mobile backs had greater activity profiles compared to other position groups. We observed that the reductions in most metabolic power variables during the course of the match are comparable to traditional running based metrics. This study demonstrates that metabolic power data may contribute to our understanding of the physical demands of Australian Football.

© 2015 Human Kinetics, Inc. Purpose: To examine the impact of varying between-matches microcycles on training characteristics (ie, intensity, duration, and load) in professional rugby league players and to report on match load related to these between-matches microcycles. Methods: Training-load data were collected during a 26-wk competition period of an entire season. Training load was measured using the session rating of perceived exertion (session-RPE) method for every training session and match from 44 professional rugby league players from the same National Rugby League team. Using the category-ratio 10 RPE scale, the training intensity was divided into 3 zones (low <4 AU, moderate ≥4-≤7 AU, and high >7 AU). Three different-length between-matches recovery microcycles were used for analysis: 5-6 d, 7-8 d, and 9-10 d. Results: A total of 3848 individual sessions were recorded. During the shorter-length between-matches microcycles (5-6 d), significantly lower training load was observed. No significant differences for subsequent match load or intensity were identified between the various match recovery periods. Overall, 16% of the training sessions were completed at the low-intensity zone, 61% at the moderate-intensity zone, and 23% at the high-intensity zone. Conclusions: The findings demonstrate that rugby league players undertake higher training load as the length of between-matches microcycles is increased. The majority of in-season training of professional rugby league players was at moderate intensity, and a polarized approach to training that has been reported in elite endurance athletes does not occur in professional rugby league.

© 2013 Sports Medicine Australia. Objectives: To determine the match-to-match variability in physical activity and technical performance measures in Australian Football, and examine the influence of playing position, time of season, and different seasons on these measures of variability. Design: Longitudinal observational study. Methods: Global positioning system, accelerometer and technical performance measures (total kicks, handballs, possessions and Champion Data rank) were collected from 33 players competing in the Australian Football League over 31 matches during 2011-2012 (N=511 observations). The global positioning system data were categorised into total distance, mean speed (mmin-1), high-speed running (>14.4kmh-1), very high-speed running (>19.9kmh-1), and sprint (>23.0kmh-1) distance while player load was collected from the accelerometer. The data were log transformed to provide coefficient of variation and the between subject standard deviation (expressed as percentages). Results: Match-to-match variability was increased for higher speed activities (high-speed running, very high-speed running, sprint distance, coefficient of variation %: 13.3-28.6%) compared to global measures (speed, total distance, player load, coefficient of variation %: 5.3-9.2%). The between-match variability was relativity stable for all measures between and within AFL seasons, with only few differences between positions. Higher speed activities (high-speed running, very high-speed running, sprint distance), but excluding mean speed, total distance and player load, were all higher in the final third phase of the season compared to the start of the season. Conclusions: While global measures of physical performance are relatively stable, higher-speed activities and technical measures exhibit a large degree of between-match variability in Australian Football. However, these measures remain relatively stable between positions, and within and between Australian Football League seasons.

© 2014, © 2014 Taylor & Francis. Abstract: The aim of this study was to compare the reliability, internal responsiveness and interchangeability of the Yo-Yo intermittent recovery test level 1 (YY1), level 2 (YY2) and submaximal YY1 (YY1-sub). Twenty-four young soccer players (age 17 ± 1 years; height 177 ± 7 cm; body mass 68 ± 6 kg) completed each test five times within pre- and in-season; distances covered and heart rates (HRs) were measured. Reliability was expressed as typical error of measurement (TEM) and intraclass correlation coefficient (ICC). Internal responsiveness was determined as effect size (ES) and signal-to-noise ratio (ESTEM). Interchangeability was determined with correlation between training-induced changes. The TEM and ICC for distances in the YY1 and YY2 and for HR in YY1-sub were 7.3% and 0.78, 7.1% and 0.93 and 2.2% and 0.78, respectively. The ESs and ESTEMs were 0.9 and 1.9 for YY1, 0.4 and 1.2 for YY2 and −0.3 and −0.3 for YY1-sub. Correlations between YY1 vs. YY2 and YY1-sub were 0.56 to 0.84 and −0.36 to −0.81, respectively. Correlations between change scores in YY1 vs. YY2 were 0.29 and −0.21 vs. YY1-sub. Peak HR was higher in YY1 vs. YY2. The YY1 and YY2 showed similar reliability; however, they were not interchangeable. The YY1 was more responsive to training compared to YY2 and YY1-sub.

The present study investigated the test-retest reliability from the Yo-Yo IR1 (distance and heart rate responses), and the ability of the Yo-Yo IR1 to differentiate between elite and non-elite youth soccer players. A total of 228 youth soccer players (11-17 years) participated: 78 non-elite players to examine the test-retest reliability within 1 week, added with 150 elite players to investigate the construct validity. The main finding was that the distance covered was adequately reproducible in the youngest age groups (U13 and U15) and highly reproducible in the oldest age group (U17). Also, the physiological responses were highly reproducible in all age groups. Moreover, the Yo-Yo IR1 test had a high-discriminative ability to distinguish between elite and non-elite young soccer players. Furthermore, age-related standards for the Yo-Yo IR1 established for elite and non-elite groups in this study may be used for comparison of other young soccer players. © 2014 Taylor & Francis.

Borges, TO, Bullock, N, Duff, C, and Coutts, AJ. Methods for quantifying training in sprint kayak. J Strength Cond Res 28(2): 474-482, 2014-The aims of this study were to determine the validity of the session rating of perceived exertion (session-RPE) method by comparing 3 different scales of perceived exertion with common measures of training load (TL). A secondary aim was to verify the relationship between TLs, fitness, and performance in Sprint Kayak athletes. After laboratory assessment of maximal oxygen uptake (V- O2peak) and lactate threshold, the athletes performed on water time trials over 200 and 1,000 m. Training load was quantified for external (distance and speed) and internal (session- RPE: 6-20, category ratio [CR]-10 and CR-100 scales, training impulse [TRIMP] , and individual TRIMP). Ten (6 male, 4 female) well-trained junior Sprint Kayak athletes (age 17.1 ± 1.2 years; V- O2peak 4.2 ± 0.7 L$min21) were monitored over a 7-week period. There were large-to-very large within-individual correlations between the session distance and the various heart rate (HR) and RPE-based methods for quantifying TL (0.58-0.91). Correlations between the mean session speed and various HR- and RPE-based methods for quantifying TL were small to large (0.12-0.50). The within-individual relationships between the various objective and subjective methods of internal TL were large to very large (0.62- 0.94). Moderate-to-large inverse relationships were found between mean session-RPE TL and various aerobic fitness variables (20.58 to 20.37). Large-to-very large relationships were found between mean session-RPE TL and on water performance (0.57-0.75). In conclusion, session-RPE is a valid method for monitoring TL for junior Sprint Kayak athletes, regardless of the RPE scale used. The session-RPE TL relates to fitness and performance, supporting the use of session-RPE in Sprint Kayak training. © 2014 National Strength and Conditioning Association.

The purpose of this investigation was to compare the criterion validity and test-retest reliability of common methods for quantifying training load. Ten (5 men and 5 women) recreational athletes (mean ± SD, V̇O 2max: 37.0 ± 4.3 ml·kg-1·min -1; age: 23.8 ± 8.4 years) completed 18 randomly assigned steady state (SS) and interval (INT) training sessions during a 6-week period. Steady-state sessions were 18 minutes in duration and were performed at 35, 50, and 65% of maximum work capacity (Wmax). Interval sessions were performed at 50, 60, and 70% of Wmax with a work to rest ratio of 1:1 and matched for total work with the 50% SS session. Oxygen consumption (V̇O2) and heart rate (HR) were measured throughout all sessions, whereas blood lactate concentration and rating of perceived exertion (RPE) measures were taken every ± minutes during sessions. Session-RPE (sRPE) was collected after each exercise bout. All individual correlations between V̇O2 and external work (r = 0.88-0.97), HR (r = 0.65-0.90), and RPE-based methods (r = 0.55-0.89) were statistically significant. External work correlated best with the total V̇O2 and was significantly different from RPE-based methods. A poor level of test-retest reliability was shown for Banister's TRIMP (15.6% coefficient of variation [CV]), Lucia's TRIMP (10.7% CV), and sRPE (28.1% CV). Good reliability was shown for HR (3.9% CV) and a moderate level for RPE 6-20 (8.5% CV) as a measure of exercise intensity. These results suggest external work to be the most valid and reliable method for quantifying training load. Poor levels of reliability were reported for each of the HR-based TRIMP methods and RPE-based methods. © 2014 National Strength and Conditioning Association.

The aims of this study were to determine the validity of the session-RPE method by comparing three different scales of perceived exertion to common measures of training load (TL). A secondary aim was to verify the relationship between training loads, fitness and performance in Sprint Kayak athletes. Following laboratory assessment of maximal oxygen uptake (VO2peak) and lactate threshold, the athletes performed on water time trials over 200 and 1000-m. TL was quantified for external (distance and speed) and internal (session-RPE: 6-20, CR-10 and CR-100 scales, TRIMP and iTRIMP). Ten (six male, four female) well-trained junior Sprint Kayak athletes (age 17.1 +/-1.2 years; VO2peak 4.2 +/-0.7 L[middle dot]min-1) were monitored over a seven-week period. There were large-to-very large within-individual correlations between session the distance and the various HR and RPE-based methods for quantifying TL (0.58 to 0.91). Correlations between mean session speed and various HR and RPE-based methods for quantifying TL were small-to-large (0.12 to 0.50). The within-individual relationships between the various objective and subjective methods of internal TL were large-to-very large (0.62 to 0.94). Moderate-to-large inverse relationships were found between mean session-RPE TL and various aerobic fitness variables (-0.58 to -0.37). Large-to-very large relationships were found between mean session-RPE TL and on water performance (0.57 to 0.75). In conclusion, session-RPE is a valid method for monitoring TL for junior Sprint Kayak athletes, regardless of the RPE scale is used. The session-RPE TL relate to fitness and performance, supporting the use of session-RPE in Sprint Kayak training.

Objectives: To examine the influence of quarter outcome and the margin of the score differential on both the physical activity profile and skill performance of players during professional Australian Football matches. Design: Prospective, longitudinal. Methods: Physical activity profiles were assessed via microtechnology (Global Positioning System and accelerometer) from 40 professional AF players from the same team during 15 Australian Football League games. Skill performance measures (involvement and effectiveness) and player rank scores (Champion Data© Rank) were provided by a commercial statistical provider. The physical performance variables, skill involvements and individual player performance scores were expressed relative to playing time for each quarter. The influence of the quarter result (i.e. win vs. loss) and score margin (i.e. small: <9 points, moderate: 10-18 points, and large: >19 points) on activity profile and skill involvements and skill efficiency performance of players were examined. Results: Skill involvements (total disposals/min, long kicks/min, marks/min, running bounces/min and player rank/min) were greater in quarters won (all p<0.01). In contrast, the players high speed running distance per minute (>14.5kmh-1, HSR/min), sprints/min and peak speed were higher in losing quarters (all p<0.01). Smaller score margins were associated with increased physical activity (m/min, HSR/min, and body load/min, all p<0.05) and decreased skill efficiency (handball clangers/min and player rank/min, all p<0.05). Conclusions: Professional AF players are likely to have an increased physical activity profile and decreased skill involvement and proficiency when their team is less successful. © 2013 Sports Medicine Australia.

PURPOSE: The purpose of this study is to examine whether performance supercompensation during taper is maximized in endurance athletes after experiencing overreaching during an overload training (OT) period. METHODS: Thirty-three trained male triathletes were assigned to either OT (n = 23) or normal training groups (n = 10, CTL) during 8 wk. Cycling performance and maximal oxygen uptake (V̇O2max) were measured after 1 wk of moderate training, a 3-wk period of OT, and then each week during 4-wk taper. RESULTS: Eleven of the 23 subjects from the OT group were diagnosed as functionally overreached (F-OR) after the overload period (decreased performance with concomitant high perceived fatigue), whereas the 12 other subjects were only acutely fatigued (AF) (no decrease in performance). According to qualitative statistical analysis, the AF group demonstrated a small to large greater peak performance supercompensation than the F-OR group (2.6% ± 1.1%) and the CTL group (2.6% ± 1.6%). V̇O2max increased significantly from baseline at peak performance only in the CTL and AF groups. Of the peak performances, 60%, 83%, and 73% occurred within the two first weeks of taper in CTL, AF, and OR, respectively. Ten cases of infection were reported during the study with higher prevalence in F-OR (70%) than that in AF (20%) and CTL (10%). CONCLUSION: This study showed that 1) greater gains in performance and V̇O2max can be achieved when higher training load is prescribed before the taper but not in the presence of F-OR; 2) peak performance is not delayed during taper when heavy training loads are completed immediately prior; and 3) F-OR provides higher risk for training maladaptation, including increased infection risks. © 2014 by the American College of Sports Medicine.

The purpose of the study was to investigate the effect of cold-water immersion (CWI) on physiological, psychological, and biochemical markers of recovery and subsequent cycling performance after intensive run training. Seven high-performance male triathletes (age: 28.6 ± 7.1 years; cycling V̇ O2peak: 73.4 ± 10.2 ml·kg-1·min -1) completed 2 trials in a randomized crossover design consisting of 7 × 5-minute running intervals at 105% of individual anaerobic threshold followed by either CWI (10 ± 0.5°C) or thermoneutral water immersion (TNI; 34 ± 0.5°C). Subjects immersed their legs in water 5 times for 60 seconds with 60-second passive rest between each immersion. Nine hours after immersion, inflammatory and muscle damage markers, and perceived recovery measures were obtained before the subjects completed a 5-minute maximal cycling test followed by a high-quality cycling interval training set (6 3 5-minute intervals). Power output, heart rate, blood lactate (La), and rating of perceived exertion (RPE) were also recorded during the cycling time-trial and interval set. Performance was enhanced (change, 690% confidence limits) in the CWI condition during the cycling interval training set (power output [W·kg -1], 2.1 ± 1.7%, La [mmol·L-1], 18 ± 18.1%, La:RPE, 19.8 ± 17.5%). However, there was an unclear effect of CWI on 5-minute maximal cycling time-trial performance, and there was no significant influence on perceptual measures of fatigue/recovery, despite small to moderate effects. The effect of CWI on the biochemical markers was mostly unclear, however, there was a substantial effect for interleukin-10 (20 ± 13.4%). These results suggest that compared with TNI, CWI may be effective for enhancing cycling interval training performance after intensive interval-running training. © 2014 National Strength and Conditioning Association.

© 2014 Zhang et al. Background: The switching exercise (e.g., Interval Training) has been a commonly used exercise protocol nowadays for the enhancement of exerciser's cardiovascular fitness. The current difficulty for simulating human onset and offset exercise responses regarding the switching exercise is to ensure the continuity of the outputs during onset-offset switching, as well as to accommodate the exercise intensities at both onset and offset of exercise. Methods: Twenty-one untrained healthy subjects performed treadmill trials following both single switching exercise (e.g., single-cycle square wave protocol) and repetitive switching exercise (e.g., interval training protocol). During exercise, heart rate (HR) and oxygen uptake (VO2) were monitored and recorded by a portable gas analyzer (K4b2, Cosmed). An equivalent single-supply switching resistance-capacitor (RC) circuit model was proposed to accommodate the observed variations of the onset and offset dynamics. The single-cycle square wave protocol was utilized to investigate the respective dynamics at onset and offset of exercise with the aerobic zone of approximate 70% - 77% of HRmax, and verify the adaption feature for the accommodation of different exercise strengths. The design of the interval training protocol was to verify the transient properties during onset-offset switching. A verification method including Root-mean-square-error (RMSE) and correlation coefficient, was introduced for comparisons between the measured data and model outputs. Results: The experimental results from single-cycle square wave exercises clearly confirm that the onset and offset characteristics for both HR and VO2are distinctly different. Based on the experimental data for both single and repetitive square wave exercise protocols, the proposed model was then presented to simulate the onset and offset exercise responses, which were well correlated indicating good agreement with observations. Conclusions: Compared with exis

This study examined the birth distribution for adolescent (i.e. <20 years) and mature age players (i.e. ≥20 years) selected in the Australian Football League (AFL) National Draft between 2001 and 2012. Birth-date information was accessed for all first time AFL national draftees and players were then classified as either adolescent (N = 736) or mature age (N = 70) draftees. Chi-squared analysis showed a clear bias in the birth distribution of adolescent draftees towards players born in the first part of the classification period for both quartile (P < 0.001) and half-year (P < 0.001) compared to the Australian national population. There was a reverse relative age effect (RAE) for mature age draftees, with a significant bias towards players born in the latter part of the selection period for both quartile (P = 0.047) and half-year (P = 0.028) compared to the Australian national population. The selection bias towards relatively older players in adolescent AFL draftees may be related to advanced physical and psychological maturity, and exposure to higher-level coaching compared to their younger counterparts. The reverse RAE in mature age draftees is a novel finding and supports the need for strategies to encourage continued participation pathways for talented Australian football players born later in the selection year. © 2013 © 2013 Taylor & Francis.

Objectives: To assess between match variability of physical performance measures over both the total and sub sections of the match in professional rugby league competition. Design: Longitudinal observational study. Methods: Global positioning system (GPS) data were collected from 24 players from the same team competing in the National Rugby League (NRL) competition over 23 matches during 2011 season. The GPS data were categorised into total distance, high-speed running (>15kmh-1) and very high-speed running (>21kmh-1) distance for discrete reference periods (10min, 20min, 40min and 80min). The data was then log transformed to provide the coefficient of variation (CV) and the between subject standard deviation (both expressed as percentages). Results: The data show that the between match variability is greater for high-speed (CV 14.6%) and very-high speed (CV 37.0%) running compared to total distance (CV 3.6%). Within each speed category, the variability of performance tended to increase as the duration of the reference period decreased. Conclusions: The results show that while global measures of physical performance such as total distance are relatively stable, higher-speed activities exhibit a large degree of between match variability. In addition, when segmenting the match into short periods of time for analysis, all physical performance measures increased in variability. These findings have implications for determining sample size, identifying reliable performance measures and selecting appropriate time periods for future applied studies that involve observational match analysis. © 2013 Sports Medicine Australia.

Purpose: The purpose of this study was to determine if Yo-Yo Intermittent Recovery level 2 (Yo-Yo IR2) and the number of interchange rotations affected the match activity profile of elite Australian footballers. Method: Fifteen elite Australian footballers completed the Yo-Yo IR2 before the beginning of the season and played across 22 matches in which match activity profiles were measured via microtechnology devices containing a global positioning system (GPS) and accelerometer. An interchange rotation was counted when a player left the field and was replaced with another player. Yo-Yo IR2 results were further split into high and low groups. Results: Players match speed decreased from 1st to 4th quarter, while average-speed (m/min: P = .05) and low-speed activity (LSA, <15 km/h) per minute (LSA m/min; P = .06) significantly decreased in the 2nd half. Yo-Yo IR2 influenced the amount of m/min, high-speed running (HSR, >15 km/h) per minute (HSR m/min) and accelerometer load/min throughout the entire match. The number of interchanges significantly influenced the HSR m/min and m/min throughout the match except in the 2nd quarter. Furthermore, the low Yo-Yo IR2 group had significantly less LSA m/min in the 4th quarter than the high Yo-Yo IR2 group (92.2 vs 96.7 m/ min, P = .06). Conclusions: Both the Yo-Yo IR2 and number of interchanges contribute to m/min and HSR m/min produced by elite Australian footballers, affecting their match activity. However, while it appears that improved Yo-Yo IR2 performance prevents reductions in LSA m/min during a match, higher-speed activities (HSR m/min) and overall physical activity (m/min and load/min) are still reduced in the 4th quarter compared with the 1st quarter. © 2013 Human Kinetics, Inc.

This study examined the influence of match-related fatigue on physical and technical skill performance in ball playing positions at two different levels of rugby league competition. Time-motion analyses were performed using global positioning systems from 6 elite National Rugby League (NRL) and 11 junior elite National Youth Competition (NYC) players from 45 matches. A standardised 5-point technical coding criteria was used to qualitatively assess skill involvements during match-play. The distance travelled in the 0-5 and 40-45 min period were significantly higher compared to the 30-35, 35-40, 70-75 and 75-80 min periods (P < 0.001). Skill rating and involvements were higher in the 0-5 and 40-45 min compared to 70-75 and 75-80 min periods (P < 0.001 and P < 0.001, respectively).There was no significant difference in the number of physical collisions between the 5-min periods (P = 0.051). Following the peak 5-min bout of exercise intensity there were reductions in distance (P < 0.001), quality of skill involvements (P < 0.001), number of involvements (P < 0.001) and collisions (P < 0.001). Elite NRL and NYC "ball players" exhibit reductions in physical performance towards the end of matches and following brief periods of intense exercise. There also appears to be a reduction in technical performance for NRL and NYC ball players, which may be attributable to match-related fatigue. © 2013 Taylor & Francis.

Scott, TJ, Black, CR, Quinn, J, and Coutts, AJ. Validity and reliability of the session-RPE method for quantifying training in Australian football: A comparison of the CR10 and CR100 scales. J Strength Cond Res 27(1): 270-276, 2013-The purpose of this study was to examine and compare the criterion validity and test-retest reliability of the CR10 and CR100 rating of perceived exertion (RPE) scales for team sport athletes that undertake high-intensity, intermittent exercise. Twenty-one male Australian football (AF) players (age: 19.0 6 1.8 years, body mass: 83.92 6 7.88 kg) participated the first part (part A) of this study, which examined the construct validity of the session- RPE (sRPE) method for quantifying training load in AF. Ten male athletes (age: 16.1 6 0.5 years) participated in the second part of the study (part B), which compared the test-retest reliability of the CR10 and CR100 RPE scales. In part A, the validity of the sRPE method was assessed by examining the relationships between sRPE, and objective measures of internal (i.e., heart rate) and external training load (i.e., distance traveled), collected from AF training sessions. Part B of the study assessed the reliability of sRPE through examining the test-retest reliability of sRPE during 3 different intensities of controlled intermittent running (10, 11.5, and 13 km.h21). Results from part A demonstrated strong correlations for CR10- and CR100-derived sRPE with measures of internal training load (Banisters TRIMP and Edwards TRIMP) (CR10: r = 0.83 and 0.83, and CR100: r = 0.80 and 0.81, p < 0.05). Correlations between sRPE and external training load (distance, higher speed running and player load) for both the CR10 (r = 0.81, 0.71, and 0.83) and CR100 (r = 0.78, 0.69, and 0.80) were significant (p < 0.05). Results from part B demonstrated poor reliability for both the CR10 (31.9% CV) and CR100 (38.6% CV) RPE scales after short bouts of intermittent running. Collectively, these results suggest both CR1

Objectives To examine with a parallel group study design the performance and physiological responses to a 14-day off-season 'live high-train low in the heat' training camp in elite football players. Methods Seventeen professional Australian Rules Football players participated in outdoor football-specific skills (32±1°C, 11.5 h) and indoor strength (23±1°C, 9.3 h) sessions and slept (12 nights) and cycled indoors (4.3 h) in either normal air (NORM, n=8) or normobaric hypoxia (14±1 h/day, FiO2 15.2-14.3%, corresponding to a simulated altitude of 2500-3000 m, hypoxic (HYP), n=9). They completed the Yo-Yo Intermittent Recovery level 2 (Yo-YoIR2) in temperate conditions (23±1°C, normal air) precamp (Pre) and postcamp (Post). Plasma volume (PV) and haemoglobin mass (Hbmass) were measured at similar times and 4 weeks postcamp (4WPost). Sweat sodium concentration ((Na+)sweat) was measured Pre and Post during a heat-response test (44°C). Results Both groups showed very large improvements in Yo-YoIR2 at Post (+44%; 90% CL 38, 50), with no between-group differences in the changes (-1%; -9, 9). Postcamp, large changes in PV (+5.6%; -1.8, 5.6) and (Na+)sweat (-29%; -37, -19) were observed in both groups, while Hbmass only moderately increased in HYP (+2.6%; 0.5, 4.5). At 4WPost, there was a likely slightly greater increase in Hbmass (+4.6%; 0.0, 9.3) and PV (+6%; -5, 18, unclear) in HYP than in NORM. Conclusions The combination of heat and hypoxic exposure during sleep/training might offer a promising 'conditioning cocktail' in team sports.

Being relatively older and having an advanced biological maturation status have been associated with increased likelihood of selection in young elite soccer players. The aims of the study were to investigate the presence of a relative age effect (RAE) and the influence of birth quarter on anthropometry, biological maturity and anaerobic parameters in 374 elite Belgian youth soccer players. The sample was divided into 3 age groups, each subdivided into 4 birth quarters (BQ). Players had their APHV estimated and height, weight, SBJ, CMJ, sprint 5 and 30 m were assessed. Overall, more players were born in BQ1 (42.3%) compared with players born in BQ4 (13.7%). Further, MANCOVA revealed no differences in all parameters between the 4 BQ's, controlled for age and APHV. These results suggest that relatively youngest players can offset the RAE if they enter puberty earlier. Furthermore, the results demonstrated possible differences between BQ1 and BQ4, suggesting that caution is necessary when estimating differences between players because of large discrepancies between statistical and practical significance. These findings also show that coaches should develop realistic expectations of the physical abilities of younger players and these expectations should be made in the context of biological characteristics rather than chronological age-based standards. © Georg Thieme Verlag KG Stuttgart. New York.

Purpose: The purpose of this study was to examine the validity of session rating of perceived exertion (sRPE) for monitoring training intensity in rugby league. Methods: Thirty-two professional rugby league players participated in this study. Training-load (TL) data were collected during an entire season and assessed via microtechnology (heart-rate [HR] monitors, global positioning systems [GPS], and accelerometers) and sRPE. Within-individual correlation analysis was used to determine relationships between sRPE and various other measures of training intensity and load. Stepwise multiple regressions were used to determine a predictive equation to estimate sRPE during rugby league training. Results: There were significant within-individual correlations between sRPE and various other internal and external measures of intensity and load. The stepwise multiple-regression analysis also revealed that 62.4% of the adjusted variance in sRPE-TL could be explained by TL measures of distance, impacts, body load, and training impulse (y = 37.21 + 0.93 distance - 0.39 impacts + 0.18 body load + 0.03 training impulse). Furthermore, 35.2% of the adjusted variance in sRPE could be explained by exercise-intensity measures of percentage of peak HR (%HRpeak), impacts/min, m/min, and body load/min (y = -0.01 + 0.37%HRpeak + 0.10 impacts/min + 0.17 m/min + 0.09 body load/min). Conclusion: A combination of internal and external TL factors predicts sRPE in rugby league training better than any individual measures alone. These findings provide new evidence to support the use of sRPE as a global measure of exercise intensity in rugby league training. © 2013 Human Kinetics, Inc.

The study aim was to investigate the effect of a periodised pre-season training plan on internal training load and subsequent stress tolerance, immune-endocrine responses and physical performance in tennis players. Well-trained young tennis players (n = 10) were monitored across the pre-season period, which was divided into 4 weeks of progressive overloading training and a 1-week tapering period. Weekly measures of internal training load, training monotony and stress tolerance (sources and symptoms of stress) were taken, along with salivary testosterone, cortisol and immunoglobulin A. One repetition maximum strength, running endurance, jump height and agility were assessed before and after training. The periodised training plan led to significant weekly changes in training loads (i.e. increasing in weeks 3 and 4, decreasing in week 5) and posttraining improvements in strength, endurance and agility (P < 0.05). Cortisol concentration and the symptoms of stress also increased in weeks 3 and/or 4, before returning to baseline in week 5 (P < 0.05). Conversely, the testosterone to cortisol ratio decreased in weeks 3 and 4, before returning to baseline in week 5 (P < 0.05). In conclusion, the training plan evoked adaptive changes in stress tolerance and hormonal responses, which may have mediated the improvements in physical performance.

Purpose: The purpose of this study was to investigate the influence of multiple games on exercise intensity during a world-class hockey tournament. Methods: 15 players (mean ± SD age 27 ± 4 y, stature 179 ± 5 cm, body mass 77 ± 5 kg, and estimated VO2 64.2 ± 3.1 mL · kg-1 · min-1) competing in the Champions Trophy (CT). Global-positioning systems assessed total distance (TD), low-speed activity (LSA; 0.10-4.17 m/s), and high-speed running (HSR; >4.17 m/s) distance. Differences in movement demands (TD, LSA, HSR) between positions and matches were assessed using the effect size and percent difference ± 90% confidence intervals. Two levels of comparison were made. First, data from subsequent matches were compared with match 1, and, second, data from each match compared with a tournament average (TA). Results: In all matches, compared with game 1, midfielders performed less HSR distance. However, the amount of HSR did not decrease as the tournament progressed. When compared with the TA, defenders showed more variation in each match. All positions showed lower movement outputs when the team won by a large margin. Conclusions: It was possible for elite team-sport athletes to maintain exercise intensity when playing 6 matches in a period of 9 days, contrary to the only other investigation of this in elite male field hockey. © 2012 Human Kinetics, Inc.