Low Pre-Season Hamstring-to-Quadriceps Strength Ratio Identified in Players Who Further Sustained In-Season Hamstring Strain Injuries: A Retrospective Study from a Brazilian Serie A Team

• Published in: Sports (Basel) Vol. 11; no. 4; p. 89
• Main Authors: Veeck, Filipe, Ruas, Cassio V, Pinto, Matheus Daros, Grazioli, Rafael, Cardoso, Gustavo Pacheco, Albuquerque, Thiago, Schipper, Lucas, Valente, Henrique Gonçalves, Santos, Victor H, Dornelles, Márcio, Rabaldo, Paulo, Rocha, Clarice S, Baroni, Bruno Manfredini, Cadore, Eduardo Lusa, Pinto, Ronei Silveira
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01-04-2023; MDPI
• Subjects: Coaches & managers; Diagnosis; football; Football players; Hamstring muscles; hamstring strain injury; Injury prevention; isokinetic; Knee; Limbs; muscle strength balance; peak torque; Physical therapists; Physical therapy; Physiological aspects; Physiological research; Professional football; Quadriceps muscle; Ratios; Soccer; Sports injuries; Training; Brazil; isokinetic; football; muscle strength balance; peak torque; hamstring strain injury
• ISSN: 2075-4663; 2075-4663
• DOI: 10.3390/sports11040089

A common pre-season injury prevention assessment conducted by professional football clubs is the hamstring-to-quadriceps (H:Q) strength ratio calculated by peak torque (PT). However, it is debatable whether players that present low pre-season H:Q ratios are more susceptible to further sustaining in-season hamstring strain injuries (HSI). Based upon retrospective data from a Brazilian Serie A football squad, a particular season came to our attention as ten out of seventeen (~59%) professional male football players sustained HSI. Therefore, we examined the pre-season H:Q ratios of these players. H:Q conventional (CR) and functional (FR) ratios, and the respective knee extensor/flexor PT from the limbs of players further sustaining in-season HSI (injured players, IP) were compared to the proportional number of dominant/non-dominant limbs from uninjured players (UP) in the squad. FR and CR were ~18-22% lower (
< 0.01), whereas quadriceps concentric PT was ~25% greater for IP than UP (
= 0.002). Low scores of FR and CR were correlated (
< 0.01) with high levels of quadriceps concentric PT (r = -0.66 to -0.77). In conclusion, players who sustained in-season HSI had lower pre-season FR and CR compared to UP, which appears to be associated with higher levels of quadriceps concentric torque than hamstring concentric or eccentric torque.