Background: The aims of this study were to (1) analyze the distribution of the player load (PLTOTAL) in 3 axes of movement (PLAP, anterior-posterior; PLML, medial-lateral; PLV, vertical) during elite soccer matches, (2) investigate the effect of playing position on PL-related variables, and (3) explore the association between PLTOTAL and distance covered by the players.
Hypothesis: Despite different load distribution between axes of movement, PLTOTAL might be used as a body load indicator for all playing positions.
Study design: Longitudinal study.
Level of evidence: Level 3.
Methods: Data were collected from elite soccer players using WIMU Pro tracking systems, which included inertial sensors.
Results: The axis of movement had a significant effect on the distribution of the load (P < 0.001; conditional R2 = 0.91), with the greatest contribution from the PLV (P < 0.001; d = 5.41-5.86). Moreover, no effect of playing position on PLTOTAL, PLV, PLML, or PLAP was observed (P > 0.05). Finally, a large correlation was found between PLTOTAL and distance covered, and the linear mixed model showed that distance may be predicted by the PLTOTAL (conditional R2 = 0.81; P < 0.001).
Conclusion: Differences in load distribution were based on the axis of movement, although playing position had no effect on any variable. The selection of either distance covered, which is representative of a 2-dimensional analysis, or PLTOTAL, which is representative of a 3-dimensional analysis, may be adequate for monitoring locomotor demands or accelerometer-derived load.
Clinical relevance: Training strategies that focus on the vertical component of match play should be adopted. In addition, given that PLTOTAL is an accelerometry-based metric, which combines the accelerations in anterior-posterior, medial-lateral, and vertical planes, strength and conditioning coaches may use this parameter as a measure of total body load.
Keywords: body load; external load; match analysis; soccer; team sports.