مقایسه تأثیر زاویه‌های مختلف مفصل زانو در دو زنجیره حرکتی باز و بسته بر نسبت فعالیت الکتریکی عضلات پهن داخلی مایل(VMO ) به پهن خارجی(VL )در حیـــن انقباض ایزومتری .

ABSTRACT There are numerous rehabilitation protocoles for Patello Femoral joint (PFJ) problems, but there is little objective data to determine the most effective treatment of this disorder. Increased VMO/VL activity ratio might be useful in treatment of patients with patellar tracking dysfunction. The purpose of this study was to investigate the EMG activty of the VMO and VL within seven angles of knee joint range of motion with isometric contraction in two commonly performed rehbilitation exercises: OKC, isometric holds(IS), and the CKC, vertical squat(SQ). The dominant knee of 44 healthy females(mean age:24.84 yearsrange:20-30 years) were analyzed. Surface electrode pairs were attached over the VMO and VL(Basmajian Method). The EMG biofeedback data were collected while the subject performed isometric contraction on IS and SQ exercises in 7 degrees from 0˚ to 90˚ (with 15˚ internals) of knee flexion. Paired t-test and Avova was performed between variables(p<0.001). This study demonstrates that there are significant differences: 1)Between OKC and CKC exercises in 0˚, 15˚, 30˚of knee flexion. 2)Between all Angles in CKC except:0-15˚, 0-30˚, 0-45˚, 15-30˚, 60-75˚, 75-90˚. 3)between: 15-60˚, 30-60˚, 45-60˚, 60-90˚ in OKC(p<0.001). A)In OKC and CKC respectively: 1/60˚ and15˚ of knee flexion was most sufficient position(increase VMO/VL activity ratios) 2/15˚ and 90˚ of knee were most insufficient position 3/The arc of movement between 45-75˚ and 0-30˚ was considered as most sufficient arc of movement. B)Because of some biomechanical & neurophysiological viewpoints that emphesized on the other literatures and also because of results of this research, our recommendations are: in early phase or in early session of treatment of PFJ dysfunction, treatment exercises done in CKC & sufficient position and after progression of patient condition OKC exercises also added.