Authors: Logan McMaster, Joshua Sponbeck, Malorie Wilwand, A. Wayne Johnson
Mentors: A Wayne Johnson
Insitution: Brigham Young University
In the dynamic game of professional football, where split-second decisions and explosive movements often determine the outcome, players train all year round for optimal athletic performance. Paramount to this performance are the hamstring muscles including the semimembranosus (SM), semitendinosus (ST), and both the long and short head of the biceps femoris (BFLH and BFSH). They play pivotal roles in sprints, agility, jumping, and overall lower-body strength. Because of the critical nature of the hamstrings during functional activity, this study sought to determine which of these three muscles contributes the most to eccentric hamstring strength. Recognizing the correlation between muscle volume and muscle strength, this study compared maximal eccentric hamstring strength with the proportion of each isolated hamstring muscle's volume relative to the total hamstring muscle group volume. Doing so would identify which specific muscle contributes the most to eccentric hamstring strength. This study incorporated 74 male, collegiate football players representing all positions on the team. Maximal strength was assessed through Nordic hamstring curls and overall muscle volume was quantified using magnetic resonance imaging (MRI). Our results show no correlation (R^2<0.2) between maximal force output and proportional muscle volume for the ST, and the BFSH. Additionally, the correlations for these muscles were not statistically significant (P>0.05). The SM muscles had a weak negative correlation (R^2= -0.25) with eccentric hamstring strength that was statistically significant (P = 0.03). The BFLH proportional volume was positively weakly correlated (R^2= 0.22) with eccentric hamstring strength. This correlation was statistically non-significant (P = 0.06). This information shows that no hamstring muscle contributes more to eccentric hamstring strength than any other. Knowledge of this can be invaluable for clinicians and researchers to design comprehensive strength training programs that enhance the collective strength of the entire hamstring muscle group, ultimately optimizing the performance of football players.