Regular heel-raise training focused on the soleus for the elderly: evaluation of muscle thickness by ultrasound

The soleus, one of the triceps surae muscles, greatly contributes to standing and walking. Strength training focused on the soleus could be important to prevent age-related deterioration in these functions. We therefore investigated the effects of regular heel-raise training focused on the soleus for the elderly. Forty-nine healthy women aged 60 to 79 years trained for at least 40 days in a period of two months. Training consisted of a set of 100 repetitions per day of heel-raise with both legs in a standing position. The training effect was evaluated by changes in each muscle thickness of the soleus and gastrocnemius medialis, which was measured using an ultrasound scanner, as well as plantar flexor strength. The subjects' ability to perform the training and their subjective opinions of its effects were assessed by a questionnaire survey. Plantar flexor strength and thicknesses of the soleus and gastrocnemius medialis were increased significantly by the training. The percentage increase in thickness was significantly greater for the soleus than for the gastrocnemius medialis (12.7% vs. 6.6%). These improvements did not significantly correlate with age. The questionnaire results suggested that the elderly were able to safely and easily perform the heel-raise training at home. This study demonstrated that regular heel-raise training is an effective muscle training method for the elderly, focused on the soleus.