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.