Investigation on lower leg muscles activity and discomfort on prolonged standing task

Prolonged static standing caused less freedom to move around and rest the muscles. This lack of flexibility in choosing body position contributes to health problems. It will accelerate fatigue besides discomfort, aching feet and swelling on leg. The aim of this study is to investigate the muscle activity and body discomfort while standing. Twelve subjects (seven females and five males) participated in experiment. Subjects performed sorting task in front of table while standing for two hours. They were sorting by pick and place object in grading table. They took MVC data before experiment. MVC used to normalize the EMG data. Selected muscles were soleus, medial gastrocnemius, lateral gastrocnemius, and tibialis anterior. Surface electromyography (sEMG) recorded muscle activity. While, Borg CR-10 scales used to rate perceived discomfort at the beginning and every 30 minutes. The results indicated that soleus was the most active muscle (higher percent MVC), followed by lateral gastrocnemius, medial gastrocnemius and tibialis anterior. The higher discomfort was found on foot, followed by ankles, lower leg and knees. It also found high discomfort at lower back. Thus, prolonged standing results fatigue on lower leg. The closer body part and muscles were to the ground, the more it be affected.