Related Experiment Video
Updated: Aug 18, 2026

Early Weight-Bearing Rehabilitation Protocol After Anterior Cruciate Ligament Reconstruction
Published on: March 1, 2024
Sport-dependent variations in arm position during single-limb landing influence knee loading: implications for
Ajit M Chaudhari1, Brenna K Hearn, Thomas P Andriacchi
1Stanford Biomotion Laboratory, Department of Mechanical Engineering, Stanford University, Stanford, California 94305-4038, USA. ajit.chaudhari@stanford.edu
Background:
Increased valgus loading at the knee has been previously identified as a possible risk factor for noncontact anterior cruciate ligament injuries, which are common in sports. Arm position variation may affect risk of injury by altering valgus knee loading.
Hypothesis:
Sport-dependent variations in arm position increase valgus loading of the knee during run-to-cut maneuvers.
Study Design:
Controlled laboratory study.
Methods:
Eleven subjects performed a sidestep cutting maneuver, first with no arm constraints and then with 3 sports-related arm positions in random order (holding a lacrosse stick, holding a football on the plant side, and holding a football on the cut side). The analysis focused on the knee valgus moment relative to the arm positions during the landing phase of the activity.
Results:
Arm position significantly influenced the valgus moment with an increase in the lacrosse trials and in the plant-side football trials but not in the cut-side football trials (alpha = .05).
Conclusions:
Constraining the plant-side arm results in increased valgus loading at the knee during run-to-cut maneuvers, which suggests the possibility of greater risk of anterior cruciate ligament injury during these conditions.
Clinical Relevance:
These results suggest that training methods that consider arm position as a risk factor could help reduce the risk of anterior cruciate ligament noncontact injury.
Related Concept Videos
Knee Joint
A total of seven ligaments support the knee joint. The patellar ligament, which is also attached to the quadriceps femoris group...
Ankle Joint
Bones of the Lower Limb: Femur and Patella
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...