The soleus muscle is one of two muscles that are located at the back of the lower leg. Together with the gastrocnemius it makes up half of the muscle group known as the calf. The soleus is a powerful muscle but if it isn’t functioning correctly it can cause a number of conditions such as knee and ankle pain. The primary function of the soleus muscle is to increase the angle between the foot and the ankle, which is also known as plantar flexion.
The soleus muscle originates behind the tibia — the large bone at the front of the shin. It runs all the way down the lower leg and inserts at the Achilles tendon. For this reason it plays a big role in ensuring the proper function of both the knee and ankle. It also indirectly affects muscles and joints elsewhere in the body.
Due to the strength of the soleus muscle, it’s one of the most important when it comes to walking and other basic movements. For this reason athletes — runners especially — need to regularly stretch the soleus to avoid it becoming tight and affecting gait. The soleus even plays an important role in standing as it’s what stops the body from falling forward.
In some cases problems in the soleus muscle can cause pain in other parts of the body such as the knee or hip. Calf muscle tears are also a common problem due to the amount of stress placed on both the soleus and gastrocnemius. A tight calf muscle can affect the Achilles tendon and make injuries such as tendinitis more probable.
Regularly stretching the soleus muscle can help to keep the muscle loose and flexible. This in turn helps to ensure that the skeletal system is working as it should. A simple soleus stretch can be performed by placing one leg behind the other while facing a wall. Bending the back leg a small amount the front knee is also bent to provide a stretch. A stretch should never be pushed too far and should be held for around 30 seconds to achieve the maximum benefit.
The gastrocnemius is sometimes considered to be part of the same muscle as the soleus because they work in similar ways. Like the soleus muscle it inserts behind the knee and goes down the back of the leg to the ankle. Stretching the gastrocnemius requires a straight knee while a soleus stretch requires a bent knee, however.