PlayerLoad Variables Are Sensitive to Changes in Direction and Not Related to Collision Workloads in Rugby League Match-Play

Hulin, B. T., Gabbett, T. J., Johnston, R. D., Jenkins, D. G.

Purpose: Determine: 1) how change of direction (COD) workloads influence PlayerLoad variables when controlling total distance covered, and 2) relationships among collision workloads and PlayerLoad 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 each protocol was the COD demands required to complete 1 repetition; no COD (SL), 1 x 180° COD (1COD), or 3 x 180° COD (3COD). During rugby league matches, relationships among collision workloads, tri-axial PlayerLoad (PLVM), anterior-posterior + medio-lateral PlayerLoad (PL2D), and PLVM accumulated at locomotor velocities below 2 m.sec^-1 (i.e. PLSLOW) were examined using Pearson correlations (r) with coefficients of determination (R^2).

Results: Comparing 3COD to SL 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.min^-1 demonstrated a distinct (i.e. R^2 <0.50) relationship from PLVM.min^-1 (R^2 = 0.30, r = 0.55), and PL2D.min^-1 (R^2 = 0.37, r = 0.61). Total distance.min^-1 demonstrated a very large relationship with PLVM.min^-1 (R^2 = 0.62, r = 0.79), and PL2D.min^-1 (R^2 = 0.57, r = 0.76). Conclusions: PlayerLoad 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. PlayerLoad variables should be used with caution to measure collision workloads in team sport.

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