A soleus stretch is any exercise intended to increase flexibility in the soleus muscle, which is a muscle in the calf. Found underneath the gastrocnemius, the large two-headed muscle that is visible when flexing the calf, the soleus is a slightly smaller muscle that originates below the knee on both the tibia and fibula bones and runs vertically downward, attaching via the Achilles tendon to the heel bone. Because it shares the Achilles with the gastrocnemius, these two muscles often work synergistically during lower leg movements.
The primary function of the soleus muscle is plantarflexion of the foot, meaning that when contracting it causes the foot to point downward. Though it assists the larger gastrocnemius in plantarflexion when the leg is straight, it plays a main role in pointing the foot when the knee is bent. As such, the soleus gets a lot of use during activities where a person is up on his toes, such as jumping, dancing, and sprinting. This is why experts recommend a soleus stretch for a variety of athletes, from dancers to basketball players. Additionally, it is often listed among the most vital stretches for runners, as the soleus sees a lot of repetitive use during distance running.
There are two commonly recommended stretches for the soleus muscle, both a bent-knee variation on gastrocnemius stretches. To perform the first soleus stretch, one should stand facing a wall with both palms flat against a wall. He would then place one foot several feet back from the wall with toes facing the wall, and place the other foot about halfway between the back foot and the wall. Maintaining upright posture, one should then bend both knees and drop the hips slightly toward the floor without lifting the back heel off the floor, feeling for a stretch in the calf of the back leg. The stretch should be held for 20-30 seconds without bouncing and then repeated on the other leg.
A more advanced version of the soleus stretch requires standing on a step on one foot with the heel off the stair, and the free leg crossed behind the ankle of the standing leg. Holding onto a stable surface for balance, one should bend the knee of the standing leg slightly and drop the heel a few inches below the edge of the step until a stretch is felt in the calf. The stretch should be held for 20-30 seconds without bouncing and then repeated on the other leg.