Comparison of quadriceps and hamstring muscle size and strength between young athletes following knee surgery and healthy controls.

Objectives: This study compared the size and strength of the quadriceps and hamstring muscles in young athletes who had undergone previous knee surgery (POST) to sex- and age- matched, healthy controls (SAM). Methods: A total of 18 (nine POST and nine SAM) participants volunteered to participate in the study's procedures. Of the nine POST participants, six had underwent anterior cruciate ligament reconstruction, two underwent medial patellofemoral ligament reconstruction and one had undergone patellar tendon repair. Maximal voluntary isometric contractions assessed absolute strength (MVIC Results: There were no significant two-way interactions ( Conclusions: These findings indicate that there was no difference in quadriceps muscle strength or size between the POST and SAM groups. However, the POST group had greater hamstrings strength than SAM yet no differences in muscle size. These results suggest that the rehabilitation program may have been effective in restoring quadriceps function and enhancing hamstrings strength in young athletes following knee surgery. However, future studies should continue to elucidate the physiological effects of knee surgeries in larger, more diverse samples to attenuate the negative musculoskeletal outcomes experienced even after successful surgery and rehabilitation. Yet, these results can be considered as preliminary findings that demonstrate the feasibility of the inclusion of ultrasound imaging in return-to-sport evaluation in a small sample.