Deviations in muscle activity alter lower-limb control after ACL injuries
Patients with ACL injuries had specific alterations in the sensorimotor control of lower limbs as indicated by deviations in muscular activity between both the injured and non-injured sides and between antagonistic muscle activity of the injured and non-injured sides, according to study results.
Researchers evaluated 16 patients between the ages of 19 years and 48 years with total, unilateral, non-reconstructed ACL ruptures. The patients’ altered movement patterns were observed and scored using the Test for Substitution Pattern (TSP). The researchers primarily used single-leg squats (SLS) and double-leg squats (DLS), as well as forward lunge, tip-toe standing knee flexion and body-weight altering, as test movements.
With surface electromyography (SEMG), the researchers evaluated the muscles, electrode placements, the procedure and pace of the test movements. Using the Swedish Knee Injury and Osteoarthritis Outcome Score, patients retrospectively rated their symptoms before injury. They also used the IKDC to rate knee-function.
According to the researchers, with SLS and DLS, TSP scores were higher in the patients’ injured side vs. the non-injured side. With SLS, transition from knee flexion to quadriceps extensions was low in both groups and with DLS, quadriceps and hamstrings transition was low.
Researchers concluded that when muscle activity is more deviating, the movement pattern is more pronounced due to correlations between specific altered movement and deviating muscle activity when in transition from the knee flexion to SLS extension. – by Monica Jaramillo