Exploring the Use of Player Load in Elite Soccer Players

Abstract

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.

Using Microtechnology and the Fourier Transform for the Analysis of Effective Activity Time in Professional Soccer

“…When the match finished, the same research team member transferred the data to SPro software (RealTrack Systems, Almería, Spain) through a Smart Station (RealTrack Systems). This software generated the "Intervals Pro report, which contained the following load measures: total of steps (count), distance covered (m), explosive distance (m, above 1.12 m•s 22 ), power metabolic (W•kg 21 ), player load (a.u), impacts (count), accelerations (count), decelerations (count), and the FFT duration (minutes) (21,27). Specifically, the FFT duration is defined as the total time in which the intensity of the FFT (i.e., a mathematic calculation that is used to convert signals from original domains such as time or space to frequency domains) is applied to the total acceleration data, which were recorded by the triaxial accelerometers (i.e., ACELT), is above 0.02.…”

“…The positioning systems provide important performance variables such as distance covered, maximum speed, and total accelerations or decelerations (29). In this regard, inertial sensors allow a 3dimensional analysis, whereas positioning-based tracking systems provide variables that are a representative of a 2dimensional analysis (e.g., distance covered) (22). Therefore, one of the main advantages of inertial sensors is that they allow further analysis of sport-specific movements such as changes of direction, jumps, impacts, body load, or landings (5,29).…”

“…For instance, a simple method might be the use of speed thresholds since activities below 7.2 km•h 21 are considered stationary (31), and these might not be representative of the effective time. However, inertial sensors such as accelerometers are necessary because not all the game's actions or periods of activity that increase the player load require high speed (e.g., jumps or impacts) (22,29). In this regard, recent studies have suggested the application of the fast Fourier transform (FFT) to the data collected by accelerometers (32).…”

Tracking devices and physical performance analysis in team sports: a comprehensive framework for research—trends and future directions

“…In a study of nine elite RH players, there were no significant differences throughout all observed metrics during a competition between players' positions (57). Furthermore, variable load distribution (total PL) based on the axis of movement was not verified based on playing position (58). However, total PL appears suitable for monitoring locomotor demands or accelerometer-derived load in FTB (58).…”

“…Furthermore, variable load distribution (total PL) based on the axis of movement was not verified based on playing position (58). However, total PL appears suitable for monitoring locomotor demands or accelerometer-derived load in FTB (58).…”