When you start talking to someone about their soleus, usually you get a strange look back as though you have just cast a spell from a Harry Potter novel.
The soleus is often the forgotten cousin of the calf complex in favour of the so hard to get hypertrophic gastrocnemius. The soleus sits deep and is hidden behind the gastrocnemius, comprising a much flatter portion of muscle that crosses the ankle but not the knee joint.
Functionally, our soleus plays a critical role in absorbing and producing force as we begin to run, absorbing between 3 and 8 times our body weight during the foot strike phase. This is significantly more than other muscle groups such as the quadriceps and hamstrings and as such we need to be confident our soleus can withstand such load.
The soleus is often a significant component of heel and calf injuries, where strength imbalances between the gastrocnemius and soleus can increase risk of injury.
An easy way to test whether you have any soleus weakness is to complete a maximal calf raise test with your knee slightly flexed to roughly 30 degrees. As the soleus doesn’t cross the knee joint while the gastrocnemius does, this position allows us to bias activation of the soleus when plantar flexing the ankle.
Once completing your maximal bent knee calf raise test, of which you should be aiming for 20+, then complete the same test with a straight knee. Also be sure to test both sides – left and right.
Ideally, your test outcomes should produce similar results between each limb and between each position, with an acceptable reduction for the bent knee calf raises as by isolating the soleus we increase the challenge than when both calf muscles can contribute.
If your tests don’t produce results such as these then perhaps you need to increase your focus on the soleus throughout your training!
Incorporating bent knee or seated calf raises, skipping and hopping exercises to your program while adequately targeting the soleus in a controlled manner will help to improve its strength and power.
From this, you will hopefully be able to see increases in your maximal calf raise test AND in your running output and recovery.
If you’re having issues with your calves while running and you’re not sure where to begin, organise a time to let our expert Physio’s point you in the right direction!
Standing calf raises versus seated calf raises