Abstract
The aim of this present study was to compare the reactive strength index (RSI) characteristics and trial to trial reliability of U17, U19 and Senior female international soccer players. Fifty – seven elite female soccer player participated in the study, (age: 18.1 + 3.1 years; height: 167.5 + 6.3 cm; weight: 61.84 + 7.7 kg). Participants performed 3 maximal repetitions of the 10/5 repeated jump test (10/5RJT) following a specific warm-up and familiarisation protocol. Senior players possessed higher levels of RSI with large effect size present when compared with the U17 (P= 0.043, ES = .97) and U19 (ES = 0.85) age groups. Trivial differences (ES = 0.17) in RSI existed between the U17 and U19 age categories. Trial-to-trial analyses demonstrated 10/5 RJT RSI to possess adequate levels of reliability with a range of mean coefficients of variance (CV) of 3.1 – 7.3 % and intraclass correlation (ICC) between 0.95 – 0.98 present across all three age groups. However, large variations in the between – athlete CV for RSI were revealed ranging from 1 – 27 %, 0.4 – 10.3%, and 1 – 7 % for U17, U19 and senior age groups respectively. These results suggest that age group can distinguish reactive strength capabilities. In addition, female international footballers with higher levels of RSI appear to produce more reliable measures of RSI via the 10/5 RJT.
Highlights
International level football players participate in numerous periods of fixture congestion whereby players are required to play in two or more games per week on numerous occasions throughout a season [1]
Senior players presented higher jump height (JH) scores as moderate (ES = 0.55) to large (ES = 1.27) effect sizes were present when compared to the U19 and U17 age groups respectively
The results of the study revealed senior players possessed superior levels of reactive strength index (RSI) primarily down to the combination of shorter contact time (CT) and increased JH during the 10/5 RJT when compared to the U17 and U19 age groups (Table 1)
Summary
International level football players participate in numerous periods of fixture congestion whereby players are required to play in two or more games per week on numerous occasions throughout a season [1]. Due to increased competition schedules, training demands, and travel full recovery postmatch play may not always be possible [2]. Football specific actions such as shooting, passing, tackling, and jumping are executed in tandem with accelerations, decelerations, and changes of direction at varying speeds. Such actions have been associated with increased levels of muscle damage, leading to a decline in muscular force production which may potentially inhibit physical performance in the subsequent days [5]. Coaches and sports science staff are employing a more scientific approach to the monitoring of their player’s training programs and competition schedules with the aim of limiting fatigue, maximising recovery, and maintaining competition readiness [1,6]
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