Patellofemoral pain syndrome and exercises
The knee joint is capable to bear weight and to produce a wide range of motion - therefore it plays an important role in activities and weight support. Patellofemoral pain syndrome (PFPS) is a common disorder, characterized by pain located anteriorly in the knee. The exact etiology has not been clearly defined yet.
Various exercises have been used in PFPS, all influencing stress in the patellofemoral joint in different ways. The aim of this study was, to investigate the effects of squat exercises with various tools such as a gym ball, a wedge and an elastic band.
Previous studies reported that abnormal tracking causes PFPS, mainly because there is an imbalance between vastus medialis obliquus (VMO) and the vastus lateralis muscles (VL). There is less activity of the VMO relative to the VL. Various exercises have been reported to aid in reducing the problems caused by PFPS, such as closed kinetic exercises (for instance squats). These exercises can influence the stress in the patellofemoral joint.
All subjects performed 4 types of the squat exercise: the conventional squat exercise, the squat exercise with a gym ball, the squat exercise with a wedge and the squat exercise with an elastic band. All of the exercises were compared to eachother and it was evaluated which exercise was most effective.
This study shows that the VMO showed more EMG activity in the squat exercise with a wedge than with an elastic band. This was the only significant difference found in this study.
When treating patients with this disorder, it is important to recognize that open chain knee extension produces relatively high levels of stress in the patellofemoral joint. Also open chain knee extension is not appropriate to selectively train the VMO, as it targets the overall strength of the quadriceps muscle.
Closed kinetic chain exercises are thought to be more effective than open kinetic chain exercises due to their stimulating effect on different structures surrounding the joint.
> From: Lee et al., J Phys Ther Sci 28 (2016) 1071-1073(Epub ahead of print). All rights reserved to IPEC Inc. Click here for the Pubmed summary.