TY - JOUR JF - RUMS_JOURNAL JO - JRUMS VL - 3 IS - 2 PY - 2004 Y1 - 2004/6/01 TI - The Role of Pretibial Muscles in the Motor Control of Quadriceps at Different Positions of the Knee and Hip Joints in Human TT - نقش عضلات قدامی ساق پا در کنترل حرکتی عضلات چهار سررانی در وضعیت‌های مختلف مفاصل زانو و ران در انسان N2 -   The Role of Pretibial Muscles in the Motor Control of Quadriceps at Different Positions of the Knee and Hip Joints in Human     K . Khademi Kalantari PhD1*    1- Assistant Professor, Dept of Physiotherapy, Faculty of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran     Background : The motor activity in muscles is the result of the interaction between central and peripheral nervous system input in the spinal cord. This interaction, which occures at the site of convergence of the common interneurones, can modify the motor activities to meet the demands of the external requirements. Stimulation of group I and II afferents in common peroneal nerve (CPN) in human elicits poly- synaptic excitation of quadriceps motoneurones. The interneurones in this pathway are the point of convergence for many ascending and descending volleys. In this study, the gain modulation of this reflex at the positions of several knee and hip joints was investigated in 14 volunteers.   Materials and Methods : Single 0.2ms pulses were delivered to CPN at the intensity of 1.5 ´ motor threshold in anterior tibials. The excitatory responses were recorded in ongoing EMG of voluntarily contracted ipsi-lateral rectus femoris at different knee and hip positions. The changes of the reflex at different intensities of contraction in rectus femoris at two knee positions of 180o & 130o, were also investigated.   Results : The CPQ reflexes showed a significant attenuation with the knee flexion and hip extension (P £ 0.001, P £ 0.01). A positive significant correlation was found between the reflex magnitude, and the level of contraction at extended knee position, however at the flexed position this correlation was not significant.   Conclusion : The results of this study indicated a strong inhibition of CPQ reflex, which is possibly raised from activation of stretch receptors in quadriceps muscles. This inhibitory effect is probably acting at premotoneuronal level.     Key words : CPQ reflex, Nervous inhibition, Knee flexion, Knee extensors, Pretibial muscles     * Corresponding author Tel: (021) 7542057   Journal of Rafsanjan University of Medical Sciences and Health Services, 2004, 3(2): 87-95   SP - 87 EP - 95 AU - Khademi Kalantari, K. AD - KW - CPQ reflex KW - Nervous inhibition KW - Knee flexion KW - Knee extensors KW - Pretibial muscles UR - http://journal.rums.ac.ir/article-1-46-en.html ER -