Heel-raise training in elderly women can increase soleus thickness within the triceps surae and improve postural control modality and stability that are effectively contributed to by leg muscle, say authors of an article published in Journal of Strength Conditioning Research. This training consists of a low-intensity exercise that requires neither special machines nor a specific environment and can be performed safely for all elderly populations, they add.
For this study, researchers assigned 26 elderly women evenly into training and control groups. Participants in the training group performed 100 heel raises per day for 2 months. The training was aimed at hypertrophy of the soleus muscle, which has a relatively high proportion (ca 90%) of slow-twitch muscle fibers and is 1 of the main postural muscles. Dynamic balance was measured while arm flexion was performed in response to a visual stimulus (simple-reaction condition) or at the participant's own pace (own-timing condition). Plantar flexion strength, thicknesses of the gastrocnemius and soleus (by ultrasound), reaction time of the anterior deltoid in the simple-reaction condition, activation onset timing of postural muscles with respect to the deltoid, movement angles of ankle and hip joints, and postural fluctuation were compared before and after the training period.
In the training group only, the following training-related effects were demonstrated: (a) increase in plantar flexor strength and thickness of the soleus; (b) shortening of the deltoid reaction time; (c) earlier activation of the erector spinae in the simple-reaction condition and the soleus in the own-timing condition; and (d) increase in ankle movement in the own-timing condition and a decrease in postural fluctuation.