Glossary
Soleus
Soleus
Pronounced: soh-lee-uhss
The soleus is a deep calf muscle beneath the gastrocnemius. It connects to the heel through the Achilles tendon and helps point the foot downwards, control forward movement of the shin and support standing. For athletes, it contributes to running, jumping and maintaining ankle control under load.
The soleus is a broad muscle in the back of the lower leg, lying beneath the gastrocnemius. It originates from the upper tibia and fibula and joins the Achilles tendon, which attaches to the calcaneus, or heel bone. Its main action is ankle plantar flexion: pointing the foot downwards or lifting the heel when the forefoot stays grounded.
The soleus helps athletes manage repeated ground contacts and control the ankle while the body moves over the foot. Its capacity matters for running, hopping and loaded movements. Understanding its role helps explain why calf training should include more than a single straight-knee exercise.
Unlike the gastrocnemius, the soleus does not cross the knee. When the foot is planted, it helps control the shin as it travels forwards over the foot. During running, it contributes to supporting and propelling the body, working with the Achilles tendon and other lower-leg muscles. Its role changes throughout ground contact rather than being limited to lifting the heel at push-off.
Seated calf raises, bent-knee standing calf raises and the stance phase of running all involve the soleus.
Include bent-knee calf work alongside straight-knee calf raises if you want to train the calf complex through different knee positions. A practical starting example is two controlled sets of 10–15 seated calf raises with a manageable load. Finish while you can still maintain the same range and tempo. Progress load or repetitions gradually, rather than increasing both at once.
In HYROX, the soleus contributes throughout the running sections and helps control the ankle during movements such as sled pushes and sandbag lunges. Bent-knee calf work can complement event preparation, but it does not replace progressive running exposure or practice of the race movements.
+What is the difference between the soleus and gastrocnemius?
Both are calf muscles that produce ankle plantar flexion. The soleus sits deeper and crosses only the ankle, while the gastrocnemius crosses both the knee and ankle. Bending the knee shortens the gastrocnemius, making the soleus relatively more prominent during calf raises.
+Do seated calf raises isolate the soleus?
No. Seated calf raises emphasise the soleus by keeping the knee bent, but other plantar-flexor muscles still contribute. Straight-knee calf raises also train the soleus; they do not switch it off.
+Should you keep training through deep calf pain?
Do not assume deep calf pain is simply a tired soleus. Stop the aggravating movement if pain is sharp, worsening or changes your gait. Persistent pain, swelling or difficulty bearing weight needs qualified assessment. Sudden calf swelling with chest pain or breathlessness requires urgent medical attention.
Also known as: Soleus muscle
The soleus is the deeper of the two main calf muscles. You may not see it as clearly as the gastrocnemius, but it works whenever you rise onto your toes and helps control your lower leg as your weight passes over a planted foot.
How can you train the soleus with control?
A seated calf raise offers a straightforward way to load the calf with the knee bent. The aim is a controlled heel lift and lowering phase, not the largest weight you can bounce through a short range.
- Sit with your knees bent roughly to a right angle and your forefeet firmly supported.
- Start without external load. If adding resistance, position it securely over the lower thighs rather than directly on the kneecaps.
- Lift your heels smoothly, then lower them under control through a comfortable range.
- Keep pressure through the forefoot without rolling onto its outer edge or curling the toes to grip.
- End the set when you can no longer maintain the movement without bouncing or shortening the range.
How should you scale calf work?
For bent-knee standing raises, use both legs and hold a stable support before progressing to single-leg work. For seated raises, reduce resistance first if control breaks down. Working from the floor limits the heel drop; adding a step increases available range and should be a deliberate progression.
When should you stop or seek advice?
Stop calf raises, running or hopping if you develop sharp calf or Achilles pain, increasing discomfort or a changed gait. Do not use this glossary entry to identify an injury or plan rehabilitation. Persistent symptoms, swelling or a sudden loss of function warrant assessment by a qualified healthcare professional.
