Impact of isoinertial training on muscle power, endurance, isometric strength, and balance: An experimental trial in post-ACL reconstruction patients

Background: Rehabilitation post Anterior Cruciate Ligament (ACL) reconstruction often results in temporary deficits in strength, endurance and neuromuscular control, Isoinertial training, with its emphasis on eccentric overload, may provide additional benefits beyond conventional rehabilitation. This study evaluated the efficacy of combining isoinertial and conventional rehabilitation on neuromuscular outcomes. Methods: A randomized controlled trial was conducted with 96 participants (aged 18–45years) three weeks of post ACL reconstruction, participants were randomized to Group A (n = 47; received intervention of Isoinertial and conventional rehabilitation) and Group B (n = 49; undergone intervention of conventional rehabilitation only). Both groups completed 6-week intervention program. Outcome measures were evaluated through flywheel ergometer for endurance, isometric strength and balance at pre- and post-intervention. Results: Both groups showed significant improvements in concentric and eccentric muscle power, isometric strength and balance (p < 0.05; effect sized = 1.25–2.45). Only Group A showed significant improvement in endurance (p < 0.001; d = 1.18). Eccentric muscle power improved more in Group A than Group B (p < 0.001; d = 3.74). Conclusion: Adding isoinertial training to conventional rehabilitation improved eccentric power and endurance beyond conventional therapy alone. These results support its integration into early ACL rehabilitation. However, the absence of long-term follow-up limits’ conclusions on sustained benefits.