Calf Muscle Injuries

What is calf muscle? 

The gastrocnemius and soleus muscles taper and merge at the base of the calf muscle. Tough connective tissue at the bottom of the calf muscle merges with the Achilles tendon. The Achilles tendon inserts into the heel bone. Soleus  muscle is known us " Peripheral heart" because of its function of bumping back blood to the heart.

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. 

Structure 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 leads to 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. Usually it looks like muscle cramp . Once we get acute injury, we have to take rest then rehabilitate as well, or else it leads to chronic calf injury.

Risk Factors Associated with Calf Injury

• 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?

Foot contact time with the ground:

• Walking = 0.6sec
• Running = 0.39 sec
• Sprinting = 0.18 – 0.2secs

What this means is: We have a long period in swing phase.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. So we have to rehabilitate as well to prevent further injury

Rehab Considerations

1. Physiotherapists need to think of the calf/foot/ankle as one ‘functional unit’. so we have to rehabilitate all of them
2. 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. 
3. Think about the person ‘bouncing’ along the ground like a kangaroo
4. Focus on the ability to hit the floor & produce as much force as you can in a short space of time – quick isometric contractions.
5. We likely need to include more soleus strengthening (seated calf raises + weight) into our rehabilitation, as well as both Gastroc & Soleus isometric holds.