Time to change direction in training load monitoring in elite football? The application of MEMS accelerometers for the evaluation of movement requirements.

ABSTRACT

In elite football, the emphasis is placed on monitoring the output from the Global Positioning Systems (GPS) component of a Micro-Electro-Mechanical Systems (MEMS) device; however, this does not comprehensively overview the total demands due to the intermittent multidirectional nature. The aim of the study was to investigate the application of accelerometer data provided by MEMS, to evaluate movement requirements in elite football. A two-staged research approach, involving an effectiveness and efficacy stage, was deployed. The effectiveness stage examined two MEMS-accelerometer variables (PlayerLoadTM (PL) and PlayerLoadTM per meter (PL.m-1)) for four years and four months. Ninety-nine English Premier League outfield football players' participated. In the efficacy stage, 26 elite outfield football players completed three different training modalities (running, possession and dribbling) and a range of MEMS-accelerometer variables were analysed. In the effectiveness stage, the mean difference in PL for all training activities other than Set Pieces were similar to Matches (-283 to -246au). Model coefficients for PL.m-1 were smallest in Team Shape (-0.00114au), Attacking (0.00025au) and Games (0.00196au), and largest for Possession (0.03356AU), Defending (0.03182au) and Skills Games (0.03106au) compared to Matches. The findings suggest that PL.m-1 but not PL may be effective at describing differences in movement requirements. In the efficacy stage, PL.m-1 and inertial movement analysis (IMA) efforts were the only variables that had greater mean differences in the smaller conditions, confirming PL.m-1's suitability in evaluating movement requirements of different training activities and pitch dimensions. The findings suggest such a variable offers value in a monitoring strategy in football.