The effect of increase in baggage weight on elderly women's lower extremity muscle activation during gait

The aim of the present study was to examine the effect of increased baggage weight on the muscle activation of elderly women's lower extremities during gait. A total of 24 elderly women who were residing in communities in Daegu, South Korea aged 79.6 +/- 6.2, 149.7 +/- 7.0 cm in height, and 53.5 +/- 7.2 kg in weight participated in this study. The muscle activation of each muscle was measured three times at 2 kg, 3 kg, and 4 kg of baggage weight while the subjects were conducting treadmill walking wearing backpacks. Electrodes were placed on four muscles: the quadriceps muscle (rectus femoris), the hamstring muscle (semitendinosus), the tibialis anterior muscle, and the soleus muscle. The results show that the rates of increase in muscle activation in the tibialis anterior and soleus muscles according to baggage weight increase were higher than those in the quadriceps and hamstring muscles (<0.05). These results indicate that the heavier weight loads increase the activation of muscles that control the ankle joints causing muscle fatigue. Moreover, a decrease in balance ability through muscle fatigue can be a risk factor for falls. Thus, elderly people should be instructed not to carry heavy objects. (C) 2014 Elsevier Ireland Ltd. All rights reserved.