Patellofemoral joint stress in (non-)weightbearing exercises
A common component of rehabilitation for patients with patellofemoral paint (PFP) includes strengthening of the quadriceps, performed both in an open- and closed-kinetic chain manner (non-weight-bearing and weight-bearing respectively). Clinicians must consider exercise prescription with respect to minimising patellofemoral joint (PFJ) loading. The aim of the following study was to compare patellofemoral joint (PFJ) stress between the two.
Lower extremity kinematics, kinetics, and electromyography of the quadriceps were recorded in 10-healthy individuals performing a weight-bearing squat, which was compared to non-weight-bearing knee extension. The squat yielded significantly greater PFJ stress at 90°, 75°, and 60° of knee flexion. In contrast, the non-weight-bearing knee extension produced significantly higher PFJ stress at 30°, 15°, and 0° of knee flexion.
These findings provide general guidelines with respect to quadriceps strengthening amongst people with PFP. To minimise PFJ stress, it is suggested that weight-bearing squats should be performed between 45° and 0° of knee flexion; whilst non-weight-bearing extension is optimally performed in the range of 90° to 45°. > From: Powers et al., J Orthop Sports Phys Ther (2014) (Epub ahead of print). All rights reserved to The Journal of Orthopaedic & Sports Physical Therapy.
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