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Journal of Strength and Conditioning Research


NFL combine, evaluation, speed, change of direction, body mass


Speed, or the time to complete straight runs or agility drills, is commonly used to assess performance in collegiate American football players. However, it is common for players' speeds to plateau by the second year of eligibility, whereas their body masses continue to increase. The purpose of this study was to track change in speed, body mass, and momentum (body mass · velocity), across Division 1 football players' 4-year careers (n = 512). Complete data were derived for the 40-yd sprint (n = 82), the proagility shuttle (n = 73), and the L drill (n = 73) from the same NCAA Division 1 team over a 15-year period. Significant changes were seen for velocity between year 1 and the next 3 playing years (p < 0.05), with no differences between years 2 and 4, whereas body mass increased significantly across all playing years (p < 0.05). Further momentum increased across all years for all tests (p < 0.0001). These results indicate the importance of including changes in body mass when evaluating performances during sprints and change of direction drills. Our results also suggest that using sprint or agility drill times to evaluate playing potential across football players' collegiate careers may be ineffective and can provide players with a false and disheartening picture of their improvements across their careers. Momentum, which incorporates training-induced increases in both speed and body mass, would be a more relevant and supportive measure of players' improvements. In addition, the simple computation of this variable, using existing speed and body mass data, may be an important addition to the National Football League combine as a measure of playing potential in the professional game.




This is the final peer-reviewed manuscript of an article first published in Journal of Strength and Conditioning Research 36, no. 2 (2022): 551–557. DOI: 10.1519/JSC.0000000000004206.

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