Gamma loop dysfunction of the quadriceps femoris of elderly patients hospitalized after fall injury.

Background And Purpose: Gamma loop dysfunction may increase the risk of falls. Therefore, we evaluated gamma loop function in subjects hospitalized after fall injury and examined whether aging affects the gamma loop.

Methods: Maximal voluntary contraction (strength) of knee extension and integrated electromyography (I-EMG) of the quadriceps femoris were examined to evaluate the activities of alpha motoneurons before and after 20-min vibration applied to the quadriceps femoris.

Knee-flexion torque and morphology of the semitendinosus after ACL reconstruction.

Purpose: The present study aimed to clarify the relationship between deficits in knee-flexion torque and morphological changes in the semitendinosus muscle-tendon complex after harvesting the semitendinosus tendon for anterior cruciate ligament (ACL) reconstruction.

Methods: Isometric knee-flexion torque at 45 and 90 degrees of knee flexion was measured in limbs of 23 patients (22 +/- 4 yr) who underwent unilateral ACL reconstruction (12-43 months postoperation) using ipsilateral semitendinosus tendon. Magnetic resonance imaging scans were used to calculate the muscle volume and the muscle length of the semitendinosus and to confirm the presence of the regenerated semitendinosus tendon.

Decrease of knee flexion torque in patients with ACL reconstruction: combined analysis of the architecture and function of the knee flexor muscles.

A decrease of deep knee flexion torque after anterior cruciate ligament (ACL) reconstruction, using a semitendinosus (and gracilis) tendon, has been reported. However, the cause of this weakness remains controversial. Architectural and functional differences in the knee flexor muscles influence this weakness.