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Part of 100+ Q&A about legs. See all.

Is there anything special or unique about the calf?

The calf is made up of two superficial muscles: the upper gastrocnemius; and the lower soleus. These are located at the back of your lower leg and join together to become your achilles tendon and attach onto your heel.

Gastrocnemius 

The bigger, upper part of your calf. This gastroc has two heads – a lateral (outside), and medial (inside). They both come from the back of your femur (thigh bone) and form into your achilles tendon. 

The gastroc is mostly made up of Type II fibres, or fast-twitched fibres. This means this muscle is important in powerful explosive movements such as sprinting, jumping and changing direction. 

Along with the soleus muscle, the gastrocnemius forms half of the calf muscle. Its function is plantar flexing the foot at the ankle joint and flexing the leg at the knee joint. The gastrocnemius is primarily involved in running, jumping and other “fast” movements of leg, and to a lesser degree in walking and standing. This specialization is connected to the predominance of white muscle fibers (type II fast twitch) present in the gastrocnemius, as opposed to the soleus, which has more red muscle fibers (type I slow twitch) and is the primary active muscle when standing still, as determined by EMG studies.

The gastrocnemius muscle is prone to spasms, which are painful, involuntary contractions of the muscle that may last several minutes.

A severe ankle dorsiflexion force may result in an injury of the muscle, commonly referred to as a “torn” or “strained” calf muscle, which is acutely painful and disabling.

The gastrocnemius muscle may also become inflamed due to overuse. Anti-inflammatory medications and physical therapy (heat, massage, and stretching) may be useful.

Anatomical abnormalities involving the medial head of gastrocnemius muscle result in popliteal artery entrapment syndrome.

Gastrocnemius muscle – animation.gif

Soleus 

This is the smaller of the two calf muscles. It sits underneath your gastrocnemius and starts from your tibia and fibula (your shin bones) rather than your femur. Then it joins with the gastrocnemius to become your achilles tendon. 

Your soleus is mostly made of Type I fibres, or slow-twitch fibres. You may think this makes it less important. But it certainly isn’t. It means the soleus has better endurance, i.e. it won’t fatigue and will be there to support you. Literally! If you didn’t have your soleus you would fall forward and face-plant!

In fact, They actually have multiple important roles. Explosive power, running, as a blood pumper, support your posture and injury prevention!

There are many injuries that can be prevented if you have decent calf strength. Some of these include: 

  • Calf tears and strains 
  • Sprained ankles 
  • Plantar fasciitis 
  • Medial Tibial Stress Syndrome (shin splints) 
  • Patellofemoral Pain 
  • Tendinopathies of the ankle and foot 
  • Tendinopathies of the knee 
  • Stress Fractures

With a strong calf complex the injuries above are less likely to happen. Some however aren’t preventable. For example; if you step in a gutter and sprain your ankle. Despite this being out of your control, having decent calf strength as a base could decrease the severity of your injury and even speed up your recovery! 

On the other hand, if you already have an injury don’t fear! Not only is calf strength important in prevention, it is also vitally important to rehabilitate many injuries!

Why is Calf Strength So Important? 

Your calf muscles propel you forward with every single step, they absorb load with each impact and they support the rest of your lower limb and body. 

By increasing your calf strength you will: 

  • Become faster 
  • Be able to run for longer 
  • Keep a more consistent pace while running 

Be able to jump higher


The talus (ankle bone) is the second largest of the tarsal bones and sits atop the calcaneus to form the subtalar joint. The tibia and fibula adjoin it on either side to form the tibiotalar joint. The talus forms a joint with four bones: tibia, fibula, calcaneus, and navicular.

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