A calf muscle strain involves overstretching or overworking of the muscles at the back of the lower leg. They occur with activities that involve sudden acceleration, jumping or changes in direction e.g. when playing netball or football. However, activities as simple as crossing the road can also result in a calf strain.

There will likely be sudden sharp pain in the calf at the time of injury and may involve a “popping” sound.

Strains vary in severity but will often result in swelling or bruising in the calf and may feel tender to touch.  Standing on your toes or stretching your calf following the injury may be difficult or limited by pain.

 Anatomy

The calf of the leg is composed of three muscles: the gastrocnemius, the soleus and the plantaris.  Collectively, this set of muscles is known as the triceps surae.  All three come together as the achilles tendon and have a common insertion point on the back of the calcaneus (heel bone).

The gastrocnemius has two parts with a medial and lateral head.  These originate above the knee joint, on either side of the base of the femur, at the femoral condyles.  This muscle primarily plantarflexes the foot (points the foot downward) and aids in knee flexion (knee bend).

The soleus is located deep to the gastrocnemius.  It originates on the upper portion of the back of the tibia and fibula (shin bones) in the lower leg. It does not cross the back of the knee. The soleus plantarflexes the foot and stabilises the tibia on top of the ankle, preventing forward translation.

The plantaris is a small muscle that crosses the back of the knee from the lateral aspect to the medial aspect of the calf.  It has small role in plantarflexion of the ankle and flexion of the knee.

All three muscles are supplied by the tibial nerve.

Grades of Severity:

Calf strains are graded based on the severity of the injury on a 1 to 3 scale.

Grade 1: The calf is overstretched causing micro tearing of the muscle fibres. There may be a sharp pain or twinge at the time but you are often able to continue with activity with either mild discomfort or no pain at all. There may be minimal loss of strength and range of motion following.  Recovery will generally take 2-4 weeks with correct management.

Grade 2: This type of strain involves partial tearing of the muscle fibres. There is often significant pain and swelling in the muscle with mild to moderate bruising. You will most likely be unable to continue activity. Pain will be felt with plantar flexing (pointing toes and foot downwards) against resistance and a there will be a clear loss of strength and range of motion. With good rehabilitation full recovery should take 4-8weeks.

Grade 3: This is the most severe calf strain which results in complete tearing or rupture of the muscle fibres. There will be severe immediate pain at the time of injury and you will not be able to continue with activity due to weakness and pain. There is often considerable swelling, bruising and tenderness following the injury. It may be difficult to contract the muscle at all and in the event of a full rupture, a gap may be felt at the site of injury. Full recovery can take at least 3-4 months, and in some cases surgery may be required.

Treatment

The main aim of treatment in the early phase is to settle inflammation and irritation, restore active range of motion at the ankle and knee to begin strengthening.

Rest is important for tissues to heal and is complimented by RICE(D) management for the first 24-72 hours.  The use of anti-inflammatories or simple pain relievers should be discussed with your GP or pharmacist.

Once there is sufficient reduction in pain and inflammation, physiotherapy management will focus on:

• Restoring active range of movement at the ankle and knee;
• Improving lower limb biomechanics and trunk control, particularly in single leg positions;
• Improving the isometric and then isotonic (concentric and eccentric) strength of the calf and quadriceps (thigh) in relation to the lower kinetic chain;
• Restoring high speed, acceleration and deceleration movements including changing direction quickly;
• Re-introducing plyometric and impact loading patterns;
• Return to activity or sport, using specific drills for longer term management.

Treatment is successfully achieved when there is no pain, when the calf and knee can be fully extended and flexed and when there is as much power and reaction speed in the lower leg and thigh as the non-injured side. In some cases strains may cause lingering pain, despite early intervention. Seek further intervention if your symptoms are unresolving.