Relationships of hamstring muscle volumes to lateral tibial slope

Background Greater posterior–inferior directed slope of the lateral tibial plateau (LTS) has been demonstrated to be a prospective ACL injury risk factor. Trainable measures to overcome a greater LTS need to be identified for optimizing injury prevention protocols. It was hypothesized that Healthy individuals with greater LTS who have not sustained an ACL injury would have a larger lateral hamstring volume. Methods Eleven healthy females (mean +/- standard deviation) (1.63 ± 0.07 m, 62.0 ± 8.9 kg, 22.6 ± 2.9 years) & 10 healthy males (1.80 ± 0.08 m, 82.3 ± 12.0 kg, 23.2 ± 3.4 years) underwent magnetic resonance imaging of the left knee and thigh. LTS, semitendinosus muscle volume, and biceps femoris long head muscle volume were obtained from imaging data. Results After controlling for potential sex confounds (R2 =.00; P =.862), lesser semitendinosus volume and greater biceps femoris-long head volume were indicative of greater LTS (R2 ∆ =.30, P =.008). Conclusions Healthy individuals with greater LTS have a muscular morphologic profile that includes a larger biceps femoris-long head volume. This may be indicative of a biomechanical strategy that relies more heavily on force generation of the lateral hamstring and is less reliant on force generation of the medial hamstring. Level of evidence Level IV.