Strength ratios are affected by years of experience in American collegiate rugby athletes: A preliminary study

BACKGROUND: Hamstring:quadriceps ratios (HQRs) have been studied as potential markers for an athlete's risk of injury, but little is known about how sport-specific experience affects HQRs. OBJECTIVE: This study compared isokinetic and isotonic strength measures, including determining HQRs, between American collegiate male rugby athletes with at least two years of experience (XP; n = 10) and those with less than two years of experience (IN; n = 14). METHODS: Isokinetic concentric (ConH) and eccentric (EccH) hamstring and concentric only quadriceps (ConQ) strength was measured at 60 and 180./s. The strength ratio: Hcon/Qcon (HQR), was calculated for both velocities, HQR60, HQR180, while the strength ratio: ConH/ConQ, the dynamic control ratio (DCR), was likewise calculated, DCR60 and DCR180. The isotonic strength was assessed via squat 1-repetition maximum. Analysis of covariance was used to examine differences between IN and XP while body weight and age served as the covariates. RESULTS: No significant differences were noted between groups in isokinetic or isotonic strength. However, a significant difference was observed in DCR60 (p = 0.047) between the two groups, with XP (0.94 ± 0.11) being greater than IN (0.81 ± 0.16). CONCLUSIONS: In view of the preliminary nature of this study, the implication of this finding is yet obscure. However, given the role of the DCR in an underlying proneness to injury, we suggest that a more comprehensive study with a substantial followup period is undertaken for uncovering the potential importance of this ratio vis-a-vis other major functional parameters as well as injury prediction and assessment of rehabilitation.