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

Article type: Research Article

Authors: Ohji, Shunsuke^{a; b; *} | Aizawa, Junya^b | Hirohata, Kenji^a | Ohmi, Takehiro^a | Mitomo, Sho^a | Koga, Hideyuki^c | Yagishita, Kazuyoshi^a

Affiliations: [a] Clinical Center for Sports Medicine and Sports Dentistry, Tokyo Medical and Dental University, Tokyo, Japan | [b] Department of Physical Therapy, Juntendo University, Tokyo, Japan | [c] Department of Joint Surgery and Sports Medicine, Tokyo Medical and Dental University, Tokyo, Japan

Correspondence: [*] Corresponding author: Shunsuke Ohji, Clinical Center for Sports Medicine and Sports Dentistry, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan. Tel.: +81 3 5803 4721; Fax: +81 3 5803 4720; E-mail: ohji.spt@tmd.ac.jp.

Abstract: BACKGROUND: 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. OBJECTIVE: This study aimed to determine the relationship between whole-body muscle mass and non-operated knee extensor strength after ACL reconstruction. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

Keywords: ACL repair, ACLR, isokinetic strength, extension torque, muscle volume

DOI: 10.3233/IES-240011

Journal: Isokinetics and Exercise Science, vol. Pre-press, no. Pre-press, pp. 1-10, 2024