Muscle Activation Patterns and Patellofemoral Pain in Cyclists.
Patellofemoral pain (PFP) is debilitating for competitive cyclists, but the mechanism for PFP is not fully understood. 10 healthy cyclists and 7 cyclists with current episodes of PFP participated in a study examining EMG timing patterns while stationary cycling.
While there was no difference in onset time for VL and VL in either group, there were temporal differences in muscle timing patterns and in activation levels. Quadriceps displayed significantly longer activation duration (22ms) for VL in injured cyclists, with VL activated earlier and remaining active longer.
In the Hamstring group, Biceps Femoris was activated longer (70ms) in the PFP group, and also displayed greater activation (RMS values). The altered timing patterns for the VL and BF in cyclists with knee pain have implications for PF joint function, which occur at 147° which is where most force occurs in cycling, and where the PF joint is most congruent.
Increased lateral loading from altered muscle activation patterns is considered as a factor in the development of PFP in cyclists > From Dieter et al., Med Sci Sports Exerc (2013) (Epub ahead of print). All rights reserved to the American College of Sports Medicine.
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