Sports and health practitioners have been advocating for some time that poor strength and control of the hip during exercise results in excessive movement of the femur (thigh), which then places additional stress on the patellofemoral joint (front of the knee). A case series report was published in 2003 (2) which showed clinical improvement in two patients with PFPS who underwent a rehabilitation program of hip, pelvic, and trunk strengthening exercises. A number of researchers then went onto study this more closely with numerous trials being performed over the past 10 years or so.
The recently published systematic review pooled the data of the best available papers that investigated hip strengthening for anterior knee pain. Seven studies were included in the review with most studies investigating differences in strength, function and pain. One study compared hip strengthening to a placebo (Omega-3 and calcium tablets), another into hip strengthening versus no intervention, however most studies (four) compared hip strengthening to knee strengthening.
The results of the review indicated that hip strengthening exercises reduced pain and improved function in people with PFPS. Of interest however, there was no evidence that hip strengthening programs actually improved hip muscle strength! So how does that work? Some differences in the amount of supervision between groups and the type of exercises performed (isometric versus concentric/eccentric) were discussed by the authors of the review, but my personal feeling is that hip strengthening exercises improve hip muscle activation and control, rather than a raw increase in strength, which results in better dynamic control of the leg and reduced stress on the front of the knee.
Either way, it’s quite clear that if you’re experiencing anterior knee pain your rehabilitation program should include some hip strengthening exercises. However do hip strengthening exercises help prevent knee pain in the first instance? A great question, and one that I’ll tackle in my next blog…
- Santos TR, Oliveira BA, Ocarino JM, Holt KG, Fonseca ST. Effectiveness of hip muscle strengthening in patellofemoral pain syndrome patients: a systematic review. Braz J Phys Ther. 2015 May 29:0.
- Mascal CL, Landel R, Powers C. Management of patellofemoral pain targeting hip, pelvis, and trunk muscle function: 2 case reports. J Orthop Sports Phys Ther. 2003;33(11):647-60.
- Powers CM. The influence of altered lower-extremity kinematics on patellofemoral joint dysfunction: a theoretical perspective. J Orthop Sports Phys Ther. 2003;33(11):639-46.
- Davis IS, Powers C. Patellofemoral pain syndrome: proximal, distal, and local factors, an international retreat, April 30-May 2, 2009, Fells Point, Baltimore, MD. J Orthop Sports Phys Ther. 2010;40(3):A1-16.