The Validity of a Global Navigation Satellite System for Quantifying Small-Area Team-Sport Movements

This study aimed to evaluate the validity of GNSS to quantify the mean speed (m·s−1) and acceleration (m·s−2) of movements typical to team sports. One participant completed 9 periods of 4 minutes of activity, separated by 2-minute rest periods, which involved walking, jogging, and running in a variety of directions and patterns, aimed to simulate a team-sport movement profile. Speed and acceleration were quantified from a 10-Hz GNSS unit and compared with a 10-camera, 3-dimensional motion capture system (VICON), from which the movement of both the participant's center of mass (COM) and the location of the GNSS unit (e.g., C7 vertebrae) were calculated. Practical estimates of speed were associated with small differences from both the criterion COM (effect size; ±90% confidence limits = 0.19–0.25; ± ∼0.21) and criterion C7 (0.14–0.22; ± ∼0.13). The corresponding estimates of acceleration derived from raw data were classified as small (0.16–0.22; ± ∼0.15) and small to moderate (0.25–0.35; ± ∼0.24) for the COM and C7, respectively. Software-exported acceleration values exhibited very large mean bias compared with both criterion measures (−3.81 to −3.77; ± ∼0.24). This study demonstrates that 10-Hz GNSS possess acceptable validity for assessing the average demands of movements typical of team-sports training and competition, although caution is recommended when using software-exported measures of acceleration.
Source: Journal of Strength and Conditioning Research - Category: Sports Medicine Tags: Technical Report Source Type: research