Relationship between anthropometric and kinematic measures to practice velocity in elite American 100 m sprinters

BACKGROUND: There exists a paucity of anthropometric and kinematic data for elite United States (US) sprinters and further analysis of how these variables correlate with sprint velocity in practice is warranted. AIM: The purpose of this investigation was to examine the relationship of anthropometric and kinematic variables and practice sprint velocity of elite sprint athletes when separated by gender. METHODS: Participants included elite US 100 m sprinters (total: n=38, male: n=19, female: n=19). Inclusion criteria were participation in the 100 m semifinals or finals at the US Outdoor National Championships from 2015 to 2019. Anthropometric data and 300 Hz video during maximum velocity sprinting were collected during a practice session and video was digitized to determine the kinematic variables of interest. Relationships with maximal sprint velocity were assessed using Pearson’s correlation coefficient and linear regression analysis. RESULTS: Males showed significant unadjusted relationships between practice velocity and step length (r=0.668; P=0.002), horizontal backward foot velocity at touchdown (r=0.459; P=0.048), and upper leg full extension angle (r=–0.585; P=0.009). Multiple regression analysis found that when adjusting for these three variables, step length was the only significant predictor of practice velocity in males which accounted for 44.6% of the variability in practice velocity in males. The females showed a significant relationship between practice velocity and step length (r=0.629; P=0.004) which accounted for 39.5% of the variability in practice velocity. CONCLUSION: These results provide researchers and coaches with important information regarding the anthropometric and kinematic variables related to elite top speed sprinting performance. RELEVANCE FOR PATIENTS: Training focused on increasing step length may be an efficient way to improve velocity in practice.