Effects of early inertial exercises on morphological and functional recovery after ACL reconstruction

Effective and safe rehabilitation following ACL reconstruction is an important factor in determining a patient's return to health. This pilot randomized controlled trial aimed to compare the effectiveness of two rehabilitation protocols in patients following ACL reconstruction. Twenty-four adults following anterior cruciate ligament reconstruction were randomly allocated to the study groups. The first group (SR) underwent standard rehabilitation, whereas the experimental group (SRI) performed standard rehabilitation and additional inertial exercises starting from the seventh week. After 12 weeks of rehabilitation, isokinetic and inertial strength, dynamic balance, thigh circumference, and body composition were evaluated. At the post-intervention assessment, both groups demonstrated comparable isokinetic strength and dynamic balance performance, with no significant between-group differences. In contrast, the SRI group demonstrated greater restoration of morphological symmetry and interlimb strength symmetry under inertial loading compared with the SR group (p < 0.05; Cohen's d = 1.37). Additionally, only the SRI group exhibited a significant increase in muscle mass of the operated limb, whereas no significant change was observed in the SR group. These findings indicate that early inclusion of inertial training provides additional benefits in morphological and inertial interlimb symmetry, without compromising conventional neuromuscular strength or balance outcomes following arthroscopic ACL reconstruction.