PREFERENTIAL VMO ACTIVATION ACHIEVED AS A TREATMENT FOR KNEE DISORDERS

Abstract

Patellofemoral pain (PFP), or anterior knee pain is commonly associated with atrophy of the Vastus Medialis Oblique, (VMO), and therapeutic training methods for increased VMO activation have been described as integral for treating knee disorders. PURPOSE: To compare the effect of Open Stance Cycling Protocol (OSCP) with the Traditional Cycling Foot Position (TCFP) for preferential VMO activation, measured by surface electromyography (SEMG). Preferential VMO activation was based on Vastus Medialis Oblique over Vastus Lateralis (VMO/VL) ratio values. METHODS Forty subjects participated, 18 with diagnosed patellofemoral pain and 22 asymptomatic, control subjects. (Both genders, 18 – 60 years, mean = 28.7 +/− 8). Open Stance and traditional cycling foot positions were ridden in randomized order while SEMG recordings were taken of VMO and VL muscles, collecting the mean of peak amplitudes of depolarization, to calculate VMO/VL ratio values for each protocol. The SEMG readings were taken in 4.5 second intervals, which recorded over 6 complete cycle rotations, and a randomized resistance program (random percentages of each subjects' tested max resistance) was used with a consistent cycling cadence of 85 rpm. A 2×2×2 Factorial Analysis of Variance was used to examine the results. (Dependant variable was VMO/VL ratio value, Primary independent variable was OSCP vs. TCFP, and Secondary independent variable was Symptomatic vs. control.) RESULTS There was a significant difference in the mean VMO/VL ratio values between the OSCP and the TCFP, for both symptomatic and control subjects, (F = 40.47, P = 0.001). CONCLUSION The biomechanical components of the OSCP are believed responsible for the preferential VMO activation seen in this study, and such a treatment could be effective in treating knee disorders in multiple settings. Supported by: The Institute for Sports Medicine and Health Promotion, SWTSU grant.