Altered movement patterns in individuals with ACL rupture
The underlying mechanisms of altered movement patterns in individuals with ACL injury are not fully understood. The current study assessed single and double leg squat movement patterns using surface EMG on 6 muscles of the lower limb as well as video analysis. The authors found reduced activiy in at least 3 of the 6 muscles during both squats and, interestingly, the differences were greater during the double leg squat.
Surface EMG was applied to the gluteus medius, vastus lateralis, biceps femoris, tibialis anterior, peroneus longus and gastrocnemius. A video camera captured movements from the front only. The 2 most common movement patterns observed on the injured side during SLS was increased medial displacement of the knee and lateral displacement of the trunk which correlated by lower glutues medius activity. SEMG was measured at 3 different time points - at the start of the movement, at transition from flexion to extension of the knee and at the end of the movement. A total of 18 comparisons (6 muscles at 3 time points) between injured and non injured sides were made for each subject. SLS showed 3 statiscally significant differences and the DLS showed 9. The vastus lateralis showed the most significant difference in both squats in all 3 positions. The authors also found differences in agonist/antaganist ratios between sides.
The authors concluded that these findings suggest that altered movement patterns during functional assessments are not only caused by muscle weakness but probably also by altered senserimotor control.
Are double legged tasks an important part of rehab post ACL injury or should we be prescribing only single leg exercises to restore function?
> From: Trulsson et al., BMC Musculoskelet Disord 16 (2015) (Epub ahead of print). All rights reserved to The Author(s). Click here for the Pubmed summary.
