The relationship between whole-body muscle mass and the isokinetic knee extensor strength of the non-operated side following anterior cruciate ligament reconstruction.

Recovery of the isokinetic knee extensor strength on the operated side following anterior cruciate ligament (ACL) reconstruction is commonly calculated as a ratio with the value from the non-operated side serving as the denominator. However, the validity of the values of the non-operated side remains unclear. This study aimed to determine the relationship between whole-body muscle mass and non-operated knee extensor strength after ACL reconstruction. In 27 patients who underwent ACL reconstruction, muscle mass was measured using bioelectrical impedance analysis, and bilateral concentric knee extensor strength was measured using an isokinetic dynamometer at angular velocities of 60∘/s and 180∘/s. Correlation and single regression analyses were performed to examine the relationship between whole-body muscle mass and knee extensor strength. There was a strong to very strong positive association between whole-body muscle mass and non-operated knee extensor strength (60∘/s: r= 0.85, 180∘/s: r= 0.90, P< 0.01). Univariate regression analysis showed that whole-body muscle mass was a strong predictor of non-operated knee extensor strength (R2= 0.71–0.81). Assessing both whole-body muscle mass and knee extensor strength may be used to determine whether muscle strength on the non-operated side is appropriate for the individual’s body composition. [ABSTRACT FROM AUTHOR]