The two bulkiest muscles of the calf are the gastrocnemius and soleus. Both of them attach to the Achilles tendon. Both of them exert a force to point your foot or rise up on your toes. But they have different functional roles in the body.
The soleus provides the majority of the power you need to run, especially when you’re running long distances. It’s bulkier and stronger than the gastrocnemius, and it has a larger proportion of the slow-twitch muscle fibers that are needed to keep up the pace over long distances.
The soleus also plays an important role in controlling knee alignment because it limits the forward glide of the tibia (the shinbone) when you stride forward. This protects the anterior cruciate ligament (the ACL).
Because the forces it generates are greater than those generated by the gastrocnemius, soleus muscle weakness is the most likely contributor to Achilles tendinitis and calf strain.
And due to its size, the soleus also plays a crucial role in pumping blood back to the heart. If you have a strong soleus, you’re more likely to get adequate circulation up to your brain without the blood pooling in your legs. That protects your brain from the cognitive decline associated with aging.
Strengthening of the soleus is a good idea for nearly anyone, whether you’re young or old, physically active or sedentary.
One of the best ways to strengthen the soleus is to perform heel-raising exercises while maintaining the knees in a bent position. You can make the exercise even more efficient by standing on the edge of a stair (or large book) and allowing the heels to lower below horizontal before rising up again. Give me a call or send me an e-mail and I can share with you some other tweaks that will make soleus exercise work even better for you.