Purpose : The purpose of this study was to assess the tibialis anterior, soleus, gluteus maximus, transverse abdominis muscle activity of tibialis anterior, soleus, gluteus maximus, transverse abdominis according to pronated foot and supinated foot. Methods : Group of pronation and supination were taped using augmented low-day method to make pronated and supinated foot the three case were assessed by agnostic radiology for investigating foot structure. Results : 1) When supinated foot & pronated foot, tibialis anterior & gluteus maximus muscle activity was augmented in one step. 2) When supinated foot & pronated foot, soleus & transverse abdominis muscle activity was decreased in one step. 3) When supinated foot & pronated foot, tibialis anterior & gluteus maximus muscle activity was augmented in squat. 4) When supinated foot & pronated foot, soleus muscle activity was decreased in squat. 5) When pronated foot, transverse abdominis muscle activity was decreased in squat. 6) When supinated foot, transverse abdominis muscle activity was augmented in squat. 7) When pronated foot, transverse abdominis & gluteus maximus & tibialis anterior muscle activity was augmented in sit to stand. 8) When supinated foot, transverse abdominis & gluteus maximus & tibialis anterior muscle activity was decreased in sit to stand. 9) When supinated foot & pronated foot, soleus muscle activity was decreased in sit to stand. Conclusion : 1) Pronated foot & supinated foot effects on soleus, gluteus maximus, transverse abdominis muscle activity in one step. 2) Pronated foot & supinated foot effects on tibialis anterior, gluteus maximus, transverse abdominis muscle activity in squat. 3) Pronated foot & supinated foot effects on soleus, transverse abdominis muscle activity in sit to stand. Therefore we suggest the deformity of the foot effects on tibialis anterior, soleus, gluteus maximus, transverse abdominis muscle activity.