Lower Extremity Muscle Volume As A Prediction For Sprint Speed In Collegiate Football Players

Sprinting is a crucial component of success in American football (AF) regardless of the position group. Muscle volume (MV) is a major determinant of power generation in muscles with MRI the gold standard method of measuring MV. PURPOSE: To evaluate the relationship between MV of the lower body muscles and sprint performance among different AF position groups. METHODS: As a secondary analysis from the HAMIR study, 73 (age = 23.91 ± 1.97; height = 187.93 ± 6.1; weight = 105.3 ± 20.3) actively rostered and uninjured NCAA Division I AF players participated in the study and were grouped by position: the combo group (linebackers and tight ends), the big group (offensive and defensive linemen), and the skill group (defensive backs, kickers, wide receivers, quarterbacks, and running backs). Athletes completed two sprints with distances determined by position; 40 yards for linemen and 50 yards for all other players. Athletes started from a two-point stance, self-initiated their sprint by passing through the timing gates (Brower Timing Black Box), and attempted to maintain speed through the terminal gate. Second, MV was obtained by MRI (3 T Trio, Siemens Healthineers, Erlangen, Germany). Volumetric images ranging from the psoas major to the fibularis brevis were obtained with left and right MV kept separate. The LASSSO model was used to explore which subset of the 102 MV best predicted sprint times. A linear regression using the subset of MV was performed to determine the correctness of fit between measured and predicted sprint times. RESULTS: The LASSO model indicated 42 muscles that were useful to predict running speed. Prediction of speed compared to the measure of speed was weakly correlated within the whole team (R2 = 0.26) while it was strongly correlated across the combo (R2 = 0.91), big (R2 = 0.81), and skill (R2 = 0.77) position groups. It was also significant within the whole team and all position groups (p = <0.001). CONCLUSION: This study provides compelling evidence that MV can be a useful metric for predicting sprint performance, especially in position groups. Coaches and training professionals should, in addition to strengthening protocols, consider incorporating MV assessments into their baseline assessments to use in conjunction with other performance metrics to provide a comprehensive evaluation of an AF players abilities. Supported by: NFL