12 month post-acl reconstruction quadriceps strength, neural activity, and muscle stiffness asymmetries

Arthrogenic muscle inhibition (AMI) after ACL reconstruction is a result from neural inhibition and quadriceps muscle atrophy. Asymmetrical quadriceps muscle strength has also been reported after ACLR and is associated with altered biomechanics during dynamic movement tasks. It is currently unknown if neural activity and quadriceps muscle stiffness is also asymmetrical post-ACLR. Twelve months after ACLR, patients completed isometric knee extension contractions while EMG data and shear wave ultrasound images of the quadriceps muscles were acquired. Patients demonstrated asymmetrical quadriceps strength between injured and non-injured limbs, but there were no differences in neural activity or quadriceps tissue stiffness. This study found that strength asymmetries may not be due to an underlying neural mechanisms or muscle tissue property differences.