The Soleus Muscle… A largely unknown muscle in the calf that can cause pain in the low back, calf, ankle, and foot. Symptoms of soleus muscle issues can also include circulatory issues such as varicose veins and low blood pressure, ankle instability, cramping in the calf, and swelling of the lower leg and foot! Often combined with the Gastrocnemius (gastroc) Muscle to form the Gastroc-Soleus or Triceps Surae. What is it? Where is it? And what does it do?
Where is the soleus located?
First, the soleus is located in your calf. It is wedged between the larger gastroc muscle and the tibia running from just below the knee to the heel where it joins the gastroc at the achilles tendon.
What does the soleus do?
The soleus, like the gastroc, is a plantarflexor…meaning it points the foot. It is very important in maintaining upright position when you are standing and is sometimes referred to as the skeletal muscle pump. It is called that because it is responsible for helping to pumping venous blood back up to the heart.
The soleus is an endurance muscle…
Unlike the gastroc, the soleus is composed of slow twitch fibers. This means it is meant for prolonged use, not short fast intervals. It is an endurance muscle. In patients with calf pain, the soleus often goes unchecked, yet is the source of part or all of the problem. In order to test the strength of the soleus you must bend the knee to take the gastroc out of the picture (since the gastroc crosses both the knee and ankle joints it is in a poor firing position with knee bent). Try bending the knee and then plantarflexing (pointing) the foot. Does this cause any pain? Is it difficult to do?
The soleus muscle is a magnet for trigger points…
Also, the soleus is a magnet for trigger points due to its participation in almost every activity and lack of care it receives. Trigger points in the soleus can cause low back pain as well as pain in the calf and heel. So, if you have been given a diagnosis of heel spurs, achilles tendonosis (itis), or plantar fasciitis with little response to treatment– it is worth taking a look at the soleus! Take a look at the trigger points Here.
Read more on how to prevent soleus injury and how to treat it at home! Tricky muscles like the Soleus are a great example of why it is important to be checked out by a well trained Physical Therapist!