The Shoulder and Elbow During Different Push-up Styles
Objective: Load on the wrist, elbow and shoulder during push-up performance may overload certain regions of the upper extremity causing pain and injury. Patients following wrist or elbow injury are unable to perform push-ups. During push-ups on a hyperextended wrist (HW) the forces travel more ulnarly, dorsally and in a less organized fashion than forces through the wrist when the push-up is executed on a neutral wrist (NW). The purpose of this study was to compare the trajectory of forces through the elbow and shoulder during push-ups on HW and NW. We hypothesized that these differ in force distribution through the elbow and shoulder.
Methods: Fourteen healthy right-handed male volunteers performed NW and HW push-ups. The push-ups were performed in a gait analysis laboratory using a Vicon motion capture system to follow the kinematics. The force vectors were measured using force plates and computed using Matlab software. We evaluated the forces passing through the shoulder and elbow using a reflective marker on the elbow and markers in the shoulder area.
Results: In both methods, the force was not uniform throughout the push-up and all joints moved equally in the vertical plane. The forces passed through a larger area in the shoulder than in the elbow regardless of push-up style. In NW the force passed through a more focused area in the elbow than in the HW. In NW push-ups the forces were distributed over a larger area in the shoulder than in the HW position.
Conclusions: The forces through the wrist elbow and shoulder are distributed differently during the different styles of push-up: push-ups in hyperextension load the wrist and elbow in a more diffuse fashion, the opposite is true for the shoulder. This knowledge can be translated to differentially strengthen and load certain areas in the upper extremity in rehabilitation and training.