Poor hamstrings-to-quadriceps torque ratios in male soccer players: weak hamstrings, strong quadriceps, or both?

ABSTRACT

This study aimed to evaluate the influence of hamstrings and quadriceps strength on the hamstrings-to-quadriceps conventional (H:Q_con) and functional (H:Q_fun) ratios in male soccer players. Quadriceps concentric peak torque (PT) and hamstrings concentric and eccentric PT were assessed with isokinetic dynamometry at 60°/s in 101 players (202 legs). The cut-points of 0.50, 0.55 and 0.60 were used to assess muscle imbalance through the H:Q_con ratio, while 0.80, 0.85 and 0.90 were used for H:Q_fun ratio. Legs with lower H:Q_con ratio had decreased hamstrings concentric PT (p < 0.01; moderate and large effect sizes) and increased quadriceps concentric PT (p < 0.01; moderate effect sizes) in all cut-points. Legs with lower H:Q_fun ratio had decreased hamstrings eccentric PT (p < 0.01; large effect sizes) for all cut-points, and controversial results for quadriceps concentric PT (p < 0.01 only for 0.80 cut-point; small effect sizes). H:Q_con ratio presented only weak correlations with quadriceps (r = −0.37) and hamstrings (r = 0.45) concentric PT, while H:Q_fun ratio had a negligible correlation with quadriceps concentric PT (r = −0.30) and a moderate correlation with hamstrings eccentric PT (r = 0.66). In conclusion, our findings support that hamstrings strength deficit is the key factor for low H:Q ratios in male soccer players, especially those with poor H:Q_fun ratio.

KEYWORDS:

• Football
• strength ratio
• knee extensor
• knee flexor
• muscle imbalance

Acknowledgments

CGF and MPD thank CAPES-Brazil for the scholarships. BMB thank CNPq-Brazil for the research productivity fellowship.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.