Positional differences in running and nonrunning activities during elite American football training

The aim of this investigation was to describe differences in training loads between position groups within professional American football. Integrated micro technology data were collected on 63 NFL football players during an American football training camp. Five key metrics (total distance, high-speed distance, player load (PL), PL per minute, and total inertial movement analysis [IMA]) served to quantify both running and nonrunning activities. Players were classified into position groups (defensive back [DB], defensive linemen [DL], linebacker, offensive linemen [OL], quarterback, running back, tight end, and wide receiver [WR]). Training sessions were identified by their relationship to the upcoming match (e.g., -4, -3, and -2). Running and nonrunning activities varied between position groups relative to the training day. Differences in total distance between DB and WR were observed to be unclear across the 3 training days (game day [GD] -4: 74 ± 392 m; GD -3: −122 ± 348 m; and GD -2: −222 ± 371 m). However, moderate to large differences were observed between these 2 positions and the other positional groups. A similar relationship was observed in PL and PL per minute, with the DB and WR groups performing greater amounts of load compared with other positional groups. Differences in high-speed distance varied across positional groups, indicating different outputs based on ergonomic demands. The OL and DL groups ran less but engaged in a higher amount of nonrunning activities (total IMA) with differences ranging from moderate to large across the 3 training days. Total IMA differences between offensive and defensive linemen were unclear on GD -4 (−4 ± 9) and GD -2 (−2 ± 8) and likely moderate on GD -3 (−9 ± 9). Positional differences with regard to running and nonrunning activities highlight the existence of position-specific training within a training microcycle. In addition, total IMA provides a useful metric for quantifying sport-specific movements within the game of American football.