Soleus: Functional Anatomy Guide

The soleus (L. solea, sandal.) is the smaller of the two major calf muscles; the other muscle being the gastrocnemius (gastroc).

Fun fact: It was originally named after its resemblance to the flat, sandal-shaped sole fish, whose name also comes from the Latin word, solea.

Brachialis

The soleus and gastroc are both prime movers in ankle plantarflexion when the knee is straight. However, once the knee is bent, the gastroc is inhibited and the soleus takes over as the sole prime mover. This information is critical to exercise selection, as I’ll explain this later.

It’s also worth noting that the soleus is a very important ankle stabilizer, which allows us to stand upright. Without it, we’d fall on our faces.

Note: While the soleus and the gastrocnemius are separate muscles, they are often referred to collectively as the “triceps surae” which means “three-headed muscle of the calf” (the soleus has one head, the gastroc has two). This is because of their proximity to one another; plus, they share a common function and insertion point.

Classified as part of the superficial posterior compartment of the leg, the soleus is located deep to the gastroc.

Most of its mass is invisible from the surface of the physique. However, when developed, it is clearly visible on either side of the gastroc and on the lower part of the calf.

The soleus originates from different points in or around the rear side of the fibula and inside of the tibia. It inserts on the Achilles tendon

Its fibers run obliquely between multiple septa, forming a multipennate muscle architecture.

Also Called

  • Calf
  • The second heart (a reference to its role in pumping blood back into to the heart)

Origin, Insertion, Action & Nerve Supply

Muscle Origin Insertion Action Nerve Supply
Soleus
  • Posterior surface of the head of the fibula
  • Superior quarter of the posterior surface of the fibula
  • Soleal line and middle third of medial border of tibia
  • Tendinous arch of the soleus
Posterior surface of the calcaneus via the Achilles tendon
  • Plantar flexion
  • Ankle stabilization (pulls tibia back, keeping it in place on calcaneus)
Tibial nerve (S1-S2)

Exercises:

Note: The chart below contains direct soleus training exercises only. The soleus is also trained significantly in all gastrocnemius exercises.

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Barbell:
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Stretches & Myofascial Release Techniques:

Stretches

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Self Myofascial Release Techniques

When using these techniques, give special attention to the common trigger points shown in the image below.

soleus trigger points

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Common Issues:

  • Overactive/Short Soleus: The soleus is overactive and short in individuals with lower crossed syndrome (LCS) and/or pronation distortion syndrome (PDS). In LCS, the soleus compensates for poor hip extension due to weak glutes during the gait cycle by becoming overactive to produce excessive plantarflexion. The soleus must also work harder just to maintain posture while standing since the body’s center of gravity is shifted forward. The knee adduction and foot pronation associated with PDS puts more stress on the soleus. Also, the soleus can become overactive/short via overuse from doing activities that involve a lot of plantarflexion (e.g. running, a job that requires lots of standing or walking). This overuse can contribute to LCS or PDS, or worsen them if they’re already present. An overactive and short soleus limits ankle dorsiflexion range of motion, which leads to a loss of knee flexion range of motion on exercises like the squat or leg press. This, in turn, is often compensated for by the heel lifting up at the bottom of the rep, and/or increased hip or lumbar flexion. The postural and movement distortions associated with an  soleus commonly lead to a strain or tear of the muscle or Achilles tendon. Or you could experience less acute affects, such as pain in the foot (e.g. plantar fasciitis, Achilles tendinitis), ankle, lower leg (e.g. shin splints), knee or lower back.

Training Notes:

  1. If you have overactive/short soleus, do the following:
    • If possible, reduce the amount of time spent doing high-endurance plantarflexion activities that you may be doing (e.g. running).
    • Release and stretch the soleus and gastrocnemius.
    • When the plantarflexors are overactive/short, the dorsiflexors become inhibited/long and need to be strengthened. To do this, add reverse calf raises to your training.
    • If you also have pronation distortion syndrome, you must address the other factors that contribute to it. This includes, but is not limited to: stretching/releasing the lateral gastroc, fibularis muscles, hip adductors, hip flexors and IT band, in addition to strengthening the medial gastrocnemius, glutes and hip external rotators. See pronation distortion syndrome (article coming soon) for more details.
    • If you also have lower cross syndrome, you must take care of the other issues causing it. This includes strengthening your glutes and abs/obliques, in addition to stretching and releasing your hip flexors and lower spinal erectors. See how to fix lower cross syndrome (article coming soon) for more details.
  2. If you simply want to build bigger soleus muscles to improve your calf development, use the following tips:
    • The soleus has a very high percentage of slow twitch muscle fibers. This means it is designed for endurance activities involving plantarflexion (e.g. walking, running). As such, you need to fatigue it with lighter weight and higher rep ranges to get it to respond and grow. Taking this into account, I’ve outlined the key guidelines for effective soleus training, below:
    • Do 4 sets of 10-15 reps on any bent-knee calf exercise, 2-3 times per per week.
    • Use a controlled, moderate tempo: 2 seconds down, hold a mild stretch at the bottom for 1-2 seconds, 2 seconds up, and hold a 1 second contraction at the top. Don’t bounce the weight up!
    • Rest 90 seconds between sets.
    • Don’t neglect the gastroc. See calf training for guidelines on training the entire calf.

About the Author Alex

Hey! My name is Alex, and I'm the owner and author of King of the Gym. I started this website back in late 2009 during college, and it has been my pet project ever since. My goal is to help you learn proper weight training and nutrition principles so that you can get strong and build the physique of your dreams!

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