Abstract
An important component of change of direction speed is the ability to decelerate. Objective methods to examine this quality have been rarely reported in the literature. The aim of this study was to investigate the within- and between-session reliability (intraclass correlation coefficients (ICC), coefficient of variation (CV), standard error of measurement (SEM) and smallest detectable difference (SDD)) of using a laser Doppler device (LAVEG—LAser VElocity Guard) to quantify deceleration ability in 20 amateur rugby union players. Each player performed one familiarisation and two experimental sessions (seven days apart) consisting of three maximal 15 m sprints from a standing start, with an immediate deceleration to a complete stop upon hearing an audible cue at the 15 m mark. Deceleration was evaluated by determining the distance required to decelerate to 75%, 50%, 25% and 0% (‘stopping distance’) of the velocity achieved at 15 m of the maximal sprint. Within-session relative reliability was moderate to good (ICC = 0.64–0.83) with borderline acceptable variation (CVs = 10.51%–16.71%) across all variables. Between-session reliability reported good to excellent relative reliability (ICC = 0.79–0.93) with acceptable absolute reliability, particularly for stopping distance (SEM: 6.54%; SDD: 9.11%). The assessment shows promise as a method to quantify deceleration ability in athletes.
Highlights
Rapid deceleration is observed in a variety of field
The results reveal that stopping distance from a 15 m maximal sprint has good to excellent within- and between-session reliability (ICC within = 0.82–0.83; ICC between = 0.91) and acceptable between-session absolute reliability (CV = 10.55%; SEM = 0.23 m (6.54%); SDD = 0.64 (9.11%))
The findings of the present study suggest that using laser devices such as the LAVEG is a reliable method to quantify stopping distance from a 15 m sprint task and offers a solution to quantify deceleration ability in team sport athletes
Summary
Rapid deceleration is observed in a variety of field- (i.e., soccer, rugby, American football, etc.)or court- (i.e., netball, basketball and racket sports) based sports when requiring to stop or as a precursor to a change of direction manoeuvre [1]. Rapid deceleration is observed in a variety of field- (i.e., soccer, rugby, American football, etc.). In court-based sports, due to playing area dimensions athletes may be required to decelerate rapidly over short distances, whereas in field sports such as soccer and rugby, players may be required to decelerate from varying velocities and over a variety of distances [1]. Whereas in the first and second halves of professional rugby union matches, 28.3 ± 10.6 and 25.9 ± 12.1 decelerations (≤−3 m· s−2 ) per half have been reported, respectively [4]. Playing position in both soccer [3] and rugby union [5] has been shown to influence the number of decelerations (≤−3 m·s−2 ). Performed, suggesting that distinct playing boundaries in field-based sports influence the intensity and duration of decelerations during match play [1]. Biomechanical studies have examined deceleration as a precursor to a change of direction manoeuvre, identifying the presence of distinct kinematic and kinetic differences between the ‘final’ plant step and steps preceding the change of direction manoeuvre [6,7]
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