Electromyographic activity of knee muscles in individuals with anterior cruciate ligament reconstruction under different perturbations: case report

Abstract

The aim of this case study was to describe electromyographic (EMG) activity of the knee stabilizing muscles in subjects having received different autografts in anterior cruciate ligament (ACL) surgical reconstruction: two subjects with anterior bone-tendon-bone graft, two with hamstring graft and two controls. Normalised EMG signal was collected during maximum voluntary isometric contraction (MVIC) of each muscle (vastus medialis obliques, vastus lateralis, semitendinosus, biceps femoris and gastrocnemius) and then under six perturbation stimuli at one-leg stance: on the ground, inclined and round board, balance board, anterior-posterior (AP) and medium-lateral (ML) roller-board. When comparing only extensor muscles between cases, a higher percent of MVIC was found in vastus medialis obliques and vastus lateralis in the anterior graft group (during one-leg stance, inclined board, and AP roller-board), whereas in hamstring graft cases this occurred on the round and balance boards. The analysis of flexor muscles showed greater activity on balance board and ML roller-board in subjects with hamstring graft. The amount of muscle activation thus may vary according to the stimulus. It may be said that muscles are most activated in subjects with anterior graft. These findings may guide rehabilitation of patients submitted to ACL reconstruction.