Related Experiment Video
Updated: May 9, 2026

Early Weight-Bearing Rehabilitation Protocol After Anterior Cruciate Ligament Reconstruction
Published on: March 1, 2024
Thigh muscle activity and anterior cruciate ligament insufficiency
1Department of Physical Therapy, Sackler School of Medicine, Tel-Aviv University, Israel.
Abstract:
The purpose of this study was to examine the dynamic relationship between the quadriceps femoris and hamstrings in anterior cruciate ligament (ACL) insufficiency. Thirty-five young active patients with an untreated complete tear of the ACL took part in the study. Using a KINCOM isokinetic dynamometer, the dynamic capacity of each muscle group at 30° in concentric and eccentric exertion in both the deficient and sound knee was measured. Findings demonstrated a significant reduction (P<0.05) in the torque produced by the deficient-side quadriceps compared to the sound side but no significant variations in the hamstring torque. Discussion of the findings considers a possible involvement of neurophysiological inhibition of the quadriceps as a cause for the observed weakness.
Related Concept Videos
Muscles that Move the Leg
Anterior Compartment
The quadriceps femoris, the most visible muscle of the anterior compartment, is integral for leg extension and thigh flexion. It is formed by merging four distinct muscles — the vastus lateralis, vastus medialis, vastus intermedius, and rectus femoris. The quadriceps tendon, a shared tendon of the four quadriceps muscles, is affixed to...
Muscles that Move the Thigh
Three other significant muscles are the gluteus maximus, gluteus medius, and gluteus minimus. The gluteus maximus originates from the posterior surface of the ilium, sacrum, and coccyx, and the thoracolumbar fascia...
Knee Joint
A total of seven ligaments support the knee joint. The patellar ligament, which is also attached to the quadriceps femoris group...
Bones of the Lower Limb: Femur and Patella
Muscles of the Leg that Move the Foot and Toes
Anterior Compartment
The anterior compartment includes muscles that contribute to the dorsiflexion of the foot. This compartment houses the tibialis anterior, extensor hallucis longus, and extensor digitorum longus muscles.