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Sleep duration is truncated during long-haul international travel with a 4-h time-zone delay and after night matches in elite footballers. However, this lost sleep appeared to have a limited effect on perceptual recovery, which may be explained by a westbound flight and a relatively small change in time zones, in addition to the significant increase in sleep duration on the night of arrival after the long-haul flight.

The aim of this study was to investigate the work-rate of substitutes in professional soccer. A computerised player tracking system was used to assess the work-rates of second-half substitutes (11 midfielders and 14 forwards) in a French Ligue 1 club. Total distance, distance covered in five categories of movement intensity and recovery time between high-intensity efforts were evaluated. First-and second-half work-rates of the replaced players were compared. The performance of substitutes was compared to that of the players they replaced, to team-mates in the same position who remained on the pitch after the substitution and in relation to their habitual performances when starting games. No differences in work-rate between first-and second-halves were observed in all players who were substituted. In the second-half, a non-significant trend was observed in midfield substitutes who covered greater distances than the player they replaced whereas no differences were observed in forwards. Midfield substitutes covered a greater overall distance and distance at high-intensities (p<0.01) and had a lower recovery time between high-intensity efforts (p<0.01) compared to other midfield team-mates who remained on the pitch. Forwards covered less distance (p<0.01) in their first 10-minutes as a substitute compared to their habitual work-rate profile in the opening 10-minutes when starting matches while this finding was not observed in midfielders. These findings suggest that compared to midfield substitutes, forward substitutes did not utilise their full physical potential. Further investigation is warranted into the reasons behind this finding in order to optimise the work-rate contributions of forward substitutes.

Different coaching methods are often used to improve performance. This study compared the effectiveness of 2 methodologies for speed and agility conditioning for random, intermittent, and dynamic activity sports (e.g., soccer, tennis, hockey, basketball, rugby, and netball) and the necessity for specialized coaching equipment. Two groups were delivered either a programmed method (PC) or a random method (RC) of conditioning with a third group receiving no conditioning (NC). PC participants used the speed, agility, quickness (SAQ) conditioning method, and RC participants played supervised small-sided soccer games. PC was also subdivided into 2 groups where participants either used specialized SAQ equipment or no equipment. A total of 46 (25 males and 21 females) untrained participants received (mean +/- SD) 12.2 +/- 2.1 hours of physical conditioning over 6 weeks between a battery of speed and agility parameter field tests. Two-way analysis of variance results indicated that both conditioning groups showed a significant decrease in body mass and body mass index, although PC achieved significantly greater improvements on acceleration, deceleration, leg power, dynamic balance, and the overall summation of % increases when compared to RC and NC (p < 0.05). PC in the form of SAQ exercises appears to be a superior method for improving speed and agility parameters; however, this study found that specialized SAQ equipment was not a requirement to observe significant improvements. Further research is required to establish whether these benefits transfer to sport-specific tasks as well as to the underlying mechanisms resulting in improved performance.

The effect of an early dismissal on player work-rate in a professional soccer match. AbstractThe aim of this study was to examine the effects of an early dismissal (after 5-minutes play) on work-rate in a professional soccer match. A computerised player tracking system was used to assess the work-rates of seven players who completed the match on the team with 10 players. A minute-by-minute analysis of the remaining 91mins following the dismissal was performed for the total distance covered, the distance covered in five categories of movement intensity and the recovery time between high-intensity efforts for each player. The data were calculated for each half and for three equal intervals within each half and profiled against normative data for the same players obtained from analyses of 15 games in the same season. Following the dismissal, the players covered a greater total distance than normal (p<0.025), particularly in moderate-intensity activities (p<0.01) and had shorter recovery times between high-intensity efforts (p<0.025). In contrast, there was a significant reduction between game halves for total distance covered at both the highest (p<0.025) and lowest running intensities (p<0.01). However, there were no differences in high-intensity activities across the three intervals in the second-half. These findings suggest that in 11 v 11, players may not always utilise their full physical potential as this match illustrated an increase in overall work-rate when reduced to 10 players. However, as a team with 10 players is likely to incur higher levels of fatigue, tactical alterations may be necessary and/or players may adopt a pacing strategy to endure the remainder of the match.Key terms: fatigue, football, performance, locomotor activity, sprinting, 3 Introduction A thorough understanding of the physical demands of elite soccer via information on workrates is required so that optimal training and preparation strategies can be constructed to respond to the demands of match-play. Recently, research on elite soccer has furthered our understanding of the fitness requirements and position-specific work-rate profiles of players 1 as well as identifying the occurrence of a reduced work-rate notably in the latter stages of match-play 2 .While this research has important practical implications, a recent review on motionanalysis studies in soccer 3 has identified several areas that require further exploration and especially the impact of dismissals on work-rate. Consequently, this case-study aims to explore the effects of an early dismissal on work-rate in a professional soccer match.

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One hundred and twelve finalists in the State Swimming Championships aged between seven and twelve years and 65 ranked tennis players of similar age were selected on the basis of their sporting performances. A third group comprised children of similar socio-economic status who only took part in casual sport. The tests which were used in the study were those considered to be important for successful athletic performance. A multifactorial analysis of variance and post-hoc t-tests were applied to the data to determine if any statistical differences were apparent between the three groups. The results demonstrated that no size, body shape, flexibility, strength or lung function differences were evident between the competitors and non-competitors, but that the swimmers and tennis players were superior to-the non-competitors in cardiovascular endurance. INTRODUCTIONThe question of whether champion athletes are born or made has long puzzled coaches and scientists alike. This question could possibly be clarified by using a longi-