EFFECT OF VISION ON LOWER BODY MUSCLES’ EMG ACTIVITIES DURING SQUATTING
S. Banu KELEŞ, Selim M. KADAĞAN, Ufuk ŞEKİR, Çağdaş UÇAR ŞENIŞIK, Bedrettin AKOVA, Hakan GÜR
Uludağ Üniversitesi Tıp Fakültesi, Spor Hekimliği Anabilim Dalı, Bursa
Keywords: Lower extremity, EMG activity, squatting, eyes closed
The aim of this study was to determine the changes in lower body muscles activities, and to estimate which muscles are more effective in maintaining posture during one- and two-legged squatting when vision is prevented. Ten healthy male subjects (mean age 22.0 ± 1.5 yrs) participated in the study. Vastus lateralis-VL, vastus medialis-VM, semitendinosus-ST, rectus femoris-RF, biceps femoris-BF, tibialis anterior-TA, gastrocnemius medialis-GM and gastrocnemius lateralis-GL muscular activities were analyzed by surface electromyography (EMG) during one- and two- legged squatting at 45° knee flexion. EMG records during squatting were obtained in randomized eyes open and eyes closed conditions. EMG data were normalized (nEMG) as % of root mean square of maximal voluntary isometric contractions obtained for each muscle. No significant differences were found in nEMG activities of the muscles when comparing the eyes opened and eyes closed conditions during two legged squatting. Whereas the lower leg TA and GM muscles’ nEMG activities were higher (p<0.05) in the eyes closed condition compared with the eyes opened condition, VM nEMG activities were lower (p<0.05) during one legged squatting. Therefore, it may be tentatively concluded that TA and GM muscles are more important in postural control during squatting.