Comparison of ankle plantar flexor activity between double-leg heel raise and walking

[Purpose] We aimed to evaluate the difference in the muscle activity between the double-leg heel raise (DHR) and treadmill walking. [Subjects] Thirty healthy males aged 21.5 +/- 1.6 years (body mass 63.6 +/- 9.3 kg, height 171.0 +/- 4.5 cm) participated in the study. [Methods] Electromyograms were simultaneously recorded from both heads of the gastrocnemius and the soleus of the right side during the DHR and treadmill walking. The DHR conditions were maximum plantar flexion (MPF), 3/4 MPF, 2/4 MPF, and 1/4 MPF, and the walking speeds were 20, 40, 60, 80, and 100 m/min. [Results] The muscle activity during the DHR and walking significantly increased with increments in the height of the heel raise and walking speed, respectively. Comparison of the muscle activity at MPF with that at each walking speed revealed that the muscle activity in the soleus and gastrocnemius medial head during walking exceeded that during the DHR in less than 3.3% of cases. [Conclusion] The DHR test is useful for evaluating the ankle plantar flexor activity necessary for walking.