PlayerLoad Variables: Sensitive to Changes in Direction and Not Related to Collision Workloads in Rugby League Match Play
in International Journal of Sports Physiology and PerformancePurpose: To determine (1) how change-of-direction (COD) workloads influence PlayerLoad (PL) variables when controlling total distance covered and (2) relationships among collision workloads and PL variables during rugby league match play. Methods: Participants completed 3 protocols (crossover design) consisting of 10 repetitions of a 60-m effort in 15 s. The difference between protocols was the COD demands required to complete 1 repetition: no COD (straight line), 1° × 180° COD, or 3° × 180° COD. During rugby league matches, relationships among collision workloads, triaxial vector-magnitude PlayerLoad (PLVM), anteroposterior + mediolateral PL (PL2D), and PLVM accumulated at locomotor velocities below 2 m·s−1 (ie, PLSLOW) were examined using Pearson correlations (r) with coefficients of determination (R2). Results: Comparing 3° × 180° COD to straight-line drills, PLVM·min−1 (d = 1.50 ± 0.49, large, likelihood = 100%, almost certainly), PL2D·min−1 (d = 1.38 ± 0.53, large, likelihood = 100%, almost certainly), and PLSLOW·min−1 (d = 1.69 ± 0.40, large, likelihood = 100%, almost certainly) were greater. Collisions per minute demonstrated a distinct (ie, R2 < .50) relationship from PLVM·min−1 (R2 = .30, r = .55) and PL2D·min−1 (R2 = .37, r = .61). Total distance per minute demonstrated a very large relationship with PLVM·min−1 (R2 = .62, r = .79) and PL2D·min−1 (R2 = .57, r = .76). Conclusions: PL variables demonstrate (1) large increases as COD demands intensify, (2) separate relationships from collision workloads, and (3) moderate to very large relationships with total distance during match play. PL variables should be used with caution to measure collision workloads in team sport.
Hulin and Jenkins are with the School of Human Movement and Nutrition Sciences, University of Queensland, Brisbane, QLD, Australia. Hulin is also with the Football Dept, St George Illawarra Dragons Rugby League Football Club, Wollongong, NSW, Australia. Gabbett is with Gabbett Performance Solutions, Brisbane, QLD, Australia, and the Inst for Resilient Regions, University of Southern Queensland, Ipswich, QLD, Australia. Johnston is with the School of Exercise Science, Australian Catholic University, Brisbane, QLD, Australia.
© 2019 Human Kinetics