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Acta Ortopédica Brasileira
On-line version ISSN 1809-4406
RIBEIRO, Daniel Cury et al. Electromyographical analysis of the quadriceps during knee extension at different speeds. Acta ortop. bras. [online]. 2005, vol.13, n.4, pp. 189-193. ISSN 1809-4406. http://dx.doi.org/10.1590/S1413-78522005000400008.
The patellofemoral pain syndrome (PFPS) is a common disorder of the knee; it's often caused by an excessive lateral traction of the patella. Subjects with this syndrome usually present a disruption in the activation of Vastus Mediallis Obliquus (VMO), which provides the patellar medial pull. Non-operative treatment includes quadriceps strengthening in order to promote better patellar stability and traction. Many researchers have been trying to selectively recruit the VMO, in order to improve treatments. The main purpose of this study is to investigate, using electromyography, the interference of angular speed and different ways of fixing the elastic tube on the quadriceps activity. Ten male subjects without any kind of muscle or joint injury participated in this study. Subjects with a Q angle value out of 10-15° were excluded from this study. The elastic tube was fixed parallel and oblique to the subjects' body. Knee extensions were performed at 60°/sec and 120°/sec. No selective activity of the VMO was found. By comparing the levels of muscular activity, there was an increase of the electromyographic activity level in all portions of the quadriceps at the two angular speeds, only for parallel-fixed elastic tubes. These results suggest a synergic activity between VMO and the other portions of the quadriceps.
Keywords : Rehabilitation; Electromyography; Patella; Knee injuries.