The Soleus - the Forgotten Calf Muscle

 

Most people think the calf has one muscle but there are actually two calf muscles.   The more prominent calf muscle, which is also much larger, is called Gastrocnemius.    It originates behind the knee coming from both sides of the upper leg bone – the femur.    It crosses the knee AND the ankle and attaches to the heel bone – called the calcaneus.      Gastrocnemius helps flex the knee along with the hamstrings and is key for pushing off in walking, running and jumping as it extends the forefoot down and heel up.

The often forgotten calf muscle is called Soleus.    Soleus originates from two bony points:

The shin bone – called the Tibia.  

The other lower leg bone which is called the Fibula. 

Like the Gastrocnemius it ultimately attaches to the heel bone – calcaneus.   Both calf muscles join together into the Achilles Tendon which is what ultimately attaches them both to the heel bone.

Key Functions of the Soleus

It works with the Gastrocnemius to help with push-off using the forefoot but is more active when the knee is flexed because it does not cross the knee as the Gastrocnemius does.

Another major role is to absorb force and prevent the body from falling forward when stopping or decelerating such as when you stop suddenly while running forward.

Soleus has a very high percentage of slow-twitch muscle fibers because it has to be active for all standing and walking activities.   This characteristic can be used to dramatically increase calorie burn while seated!

Skeletal muscle pump – the Soleus acts as the primary skeletal muscle pump that pushes blood back from the lower leg and feet to the heart!  It is often referred to as “the second heart” for this reason.

The Soleus “Push-Up” for Maximum Calorie Burn

In recent research done at the University of Houston – scientists designed a specific seated soleus exercise that included providing participants with visual biofeedback so they could learn to activate the soleus repeatedly in a specific way.

The results were amazing.    Participants dramatically increased calorie burn without feeling tired or overstressed!   Participants lowered blood glucose by 50%.    When they examined what fuels were being used they discovered that Soleus Push-ups used fuels from the blood unlike most muscular contractions that use fuel stored in the muscle.

Participants burned almost 100 calories per hour for many hours without being fatigued.   The trick is that these seated heel lifts must be done continuously and at a specific cadence in order to reap these benefits.   Here is a video tutorial:  https://youtu.be/pN8E3O5ZGTs?si=Xe6KtRPz3BV4yqiD

How to Strengthen the Soleus

The key exercise for strengthening the soleus is seated calf raises.   Many gyms have a plate loaded calf raise, but you can also use dumbbells or barbells on your thigh with knee bent at 90 degrees and push down and lift your heel.   Also it is best to have your forefoot elevated so your heel can move through a great range of motion when doing seated calf raises.  Since the Soleus is primarily a fast-twitch muscle fiber higher rep schemes are best – 15- 30 reps are great.