Work

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

Year: 2025

Type: article

Abstract: 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 ABS ) of the quadriceps and hamstrings. Muscle size was quantified as muscle cross-sectional area (mCSA) from panoramic ultrasound images. Relative strength (MVIC REL ) was calculated as a ratio of strength to muscle size. Separate 2-way mixed-factorial analyses of variance leg (operative or non-dominant (O-ND) vs. non-operative or dominant (NO-D)) and group (POST vs. SAM) assessed statistical differences at p ≤ 0.05. Results There were no significant two-way interactions ( p -range: 0.142–0.74) for any variables. Further, there were no significant main effects for the quadriceps ( p -range: 0.127–0.605) nor was there a main effect for leg in any hamstrings variables ( p -range: 0.126–0.367). However, the POST group had greater MVIC ABS and MVIC REL than SAM for the hamstrings by 69.8 ± 30.7 N ( p = 0.037) and 2.21 ± 1.02 N cm −2 ( p = 0.045). 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.

Source: PeerJ

DOI: 10.7717/peerj.20330