Learn More About the Calf Muscle and How to Prevent Injury
Calf injuries are one of the most prevalent muscle injuries in athletes involved in running-based sports, secondary only to hamstring injuries.
We see calf injuries as a result of sports involving a lot of high-speed running like AFL, soccer and rugby, as well as sports involving high-volumes of running load like athletics and recreational running.
Calf injuries often involve a 4-6 return-to-play rehabilitation period for a Grade 1 tear and are often more likely to occur during critical periods, such as the pre-season or during finals when athletes are fatigued.
Despite how common calf injuries are there is relatively limited knowledge of the risk factors, prognosis & recurrence of calf strains. This is quite the opposite of hamstring injuries where there is comparatively a large body of research & data!
Anatomy of the Calf
The calf complex consists of two main muscles: Gastrocnemius & Soleus, as well as several smaller accessory muscles.
A recent study showed that 62% of all calf injuries are to the Soleus muscle. Other reports suggest this figure may be upwards of 70%!
Which begs the question – are we doing enough Soleus strengthening in our rehabilitation? And, is our rehabilitation specific to how the calf muscle functions during running?
Mechanism of a Calf Injury
As with any soft-tissue muscle injury, there can be an acute ‘incident’ whereby you feel a strain/immediate onset of pain.
However, often with calf injuries (particularly soleus) there doesn’t always have to be not a specific onset of pain – often people will report their calf “pulled up tight” directly after running, or even the following day.
Risk Factors Associated with Calf Injury
As mentioned, there is currently limited research into the risk factors associated with calf injury. To date, strong evidence exists for an association between:
- Increasing player age & future calf strains. Hence, they often call it an ‘Old man’s injury.’
- There is also evidence to show that a previous calf injury within 8-weeks relates to increased risk of future strain.
How Does the Calf Work During Running?
To answer this question – it’s important to look at the amount of contact time the foot has with the ground during running.
Foot contact time with the ground:
- Walking = 0.6sec
- Running = 0.39 sec
- Sprinting = 0.18 – 0.2secs
What this means is: We have an extremely short period of foot contact time (with the ground) for the calf muscles to actively transfer load & propel us forwards.
So technically – we end up with a very quick isometric (static) contraction of the calf complex, supported by the spring of the tendon & fascia. This is important to consider & build into someone’s rehabilitation, especially when preparing a client/athlete to return to running.
Rehab Considerations
- Physiotherapists need to think of the calf/foot/ankle as one ‘functional unit’
- Introduce the concept of the lower limb as a ‘spring’, and creating ‘stiffness’ throughout the calf/foot/ankle unit during running. You can train Stiffness.
- Think about the person ‘bouncing’ along the ground like a kangaroo
- Focus on the ability to hit the floor & produce as much force as you can in a short space of time – quick isometric contractions.
- We likely need to include more soleus strengthening (seated calf raises + weight) into our rehabilitation, as well as both Gastroc & Soleus isometric holds.
If you have any questions, or would like to improve technique/efficiency please feel free to contact me at the clinic. [email protected].