Beyond peak torque: Longitudinal analysis of angle-specific isokinetic knee in athletes

Objectives: To investigate changes in angle-specific knee extensor torque between limbs from 4 to 12 months post-anterior cruciate ligament reconstruction(ACLR) in Division I collegiate athletes at two different isokinetic velocities. Design: Case-series study. Setting: Laboratory-based. Participants: Isokinetic knee flexion and extension assessments of 17 athletes (11 female) at 4, 8, and 12 months after ACLR with bone-patellar tendon-bone autograft were evaluated. Main outcome measures: Angle-specific curve analyses were performed using statistical parametric mapping for torque data obtained between 14 and 101 degrees at 60 degrees/s and 240 degrees/s velocities. Results: At 60 degrees/s, knee extensor torque of the operated limb increased between 4 and 8 months (18 -101 degrees,p < 0.001), 4 and 12 months (28-101 degrees,p < 0.001), and 8 and 12 months post-surgery (62 -70 degrees,p = 0.002, and 79-90 degrees,p < 0.001). Knee extensor torque was lower in the operated limb compared to the non-operated limb at 4 (47-97 degrees,p < 0.001) and 8 months (65-90 degrees,p < 0.001) for 60 degrees/s, at 4 (21 -89 degrees,p < 0.001) and 8 months (50-77 degrees,p < 0.001) for 240 degrees/s, with no between-limb differences at 12 months post-ACLR for both velocities. Conclusions: Operated limb knee extensor torque increased throughout the majority of knee range of motion from 4 to 12 months post-ACLR at both isokinetic velocities, while non-operated limb torque only improved through a reduced arc of motion in greater knee flexion angles. (c) 2023 Elsevier Ltd. All rights reserved.