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When it comes to triathlon, and running in particular, the calves are unsung heroes, contributing more to propulsion than any other muscle group. The calf muscle complex includes two main muscles, the gastrocnemius and soleus. The gastrocnemius is a two joint muscle, originating just above the knee, and attaching onto the heel via the Achilles tendon. It consists of two muscle heads, medial and lateral. The soleus originates below the knee, sits below and deep to the gastrocnemius, and merges with the gastrocnemius distally to attach onto the heel via the Achilles tendon. The gastrocnemius is the larger of the two muscles, and has a higher density of fast-twitch muscle fibers, making it a more explosive muscle that produces power for jumping and sprinting, while the soleus consists mostly of fatigue-resistant slow-twitch fibers important for endurance, making it a key contributor to distance running. Both muscles produce ankle plantarflexion (pointing the toes down), while the gastrocnemius also contributes to knee flexion.
What’s going on with calf muscle strains?
Although less common than Achilles tendon injuries, calf muscle strains still occur. But, what exactly happens when a muscle is strained? Muscle strains occur when a muscle contracts beyond its capabilities, or is overstretched, resulting in muscle damage. This often happens when the muscles are not warmed up properly, or are fatigued. A typical mechanism of gastrocnemius strains involves a rapid combination of knee extension combined with ankle dorsiflexion (pulling the foot towards the shin), which stretches the muscle at two joints. In runners, gastrocnemius strains are associated with faster than normal running, such as sprints. Because of the difference in muscle fiber composition, soleus strains tend to be overuse injuries, with slower, more gradual onsets over time, typically related to repetitive dorsiflexion while the knee is flexed- uphill running in a common mechanism. Less commonly, they may occur acutely, particularly when fatigued.
Muscle strains are graded on a scale of 1-3 depending on the amount of fiber damage. Grade 1 strains are considered “mild” strains, with less than 10% of fibers disrupted. Pain at the time of injury might be sharp, but athletes may be able to continue activity, with mild pain and tenderness, and little loss of strength. Grade 2 strains are classified as “moderate”, with 10-50% of fibers disrupted. Athletes with Grade 2 strains are generally unable to continue with activity, with greater pain and swelling, and a loss of strength. Grade 3 sprains are severe, with a 50-100% disruption of muscle fibers. These strains result in severe pain, and a total loss of muscle strength and function.
What are the symptoms of a calf strain?
All calf strains will result in pain, tenderness, and possible swelling and bruising in the calf muscles, with difficulty and weakness actively contracting the muscle to point the toes down, and pain with passive stretching. In severe strains, a palpable mass may be present. Pain is typically immediate with gastrocnemius strains, while soleus injuries present as tightness and soreness that progress over time. Pain is usually lower and deeper with soleus strains, often at the muscle/tendon junction. Because the gastrocnemius passes over both the knee and ankle joints, injuries to that muscle will be more provocative when passively dorsiflexing the ankle with the knee extended, while dorsiflexing the ankle with the knee bent isolates the soleus. The medial (inner) head of the gastrocnemius, which generates more power with sprinting, is more commonly strained than the lateral head. Some more serious conditions, such as deep vein thrombosis (blood clots), infection, peripheral nerve compression, or referred pain from nerve compression in the lower back can also cause calf pain or swelling. Risk factors, concurrent systemic symptoms, presence of numbness or tingling, and mechanism (or lack thereof) of injury need to be taken into consideration to rule out more sinister causes of pain.
What are the risk factors for calf strain?
A review study of over 5,000 athletes across a number of sports found that the strongest predictors of future calf injury were previous calf injury, and older age. While calf injuries can happen to anyone, in the general population
How to treat a calf strain
The return to activity after calf strain injuries depends on the stage of the injury, and can vary from several weeks to several months for more severe strains. Treatment of acute calf strains involves the classic RICE steps—rest, ice, compression, and elevation—in order to minimize hematoma formation, promote blood flow for healing, and decrease pain. Stretching or contracting the calf muscle complex should be avoided as much as possible. Compression can be achieved by simple ACE wraps, although compression sleeves that reach compression forces of 20-30mmHg are thought to be best to facilitate healing and potentially speed return to activity. Heel lifts are also temporarily helpful, as they decrease stretch on the calf muscles. More severe strains (Grade 3) and ruptures may require casting or splinting. Surgical repair may sometimes be required for severe injuries. Indications for surgical consultation include a palpable mass or defect,large hematomas, or prolonged pain (4-6 months) with muscle adhesions and contracture.
The subacute stages of healing involve active rehabilitation and progression back to activity. Initial rehabilitation consists of gentle range of motion exercises, and light isometric contractions at varying degrees of knee flexion, depending upon the involved calf muscle. Stretching should (still) be avoided, as it mimics the mechanism of injury, and can delay healing. Heel raises, a mainstay of Achilles tendinopathy treatment, are a key exercise in the rehabilitation of calf strains, as muscle needs to be progressively loaded in order to prepare it for sport-specific demands. A return to full training can be initiated when an athlete can walk (and then lightly run) without a limp, and perform single heel raises with no to minimal pain. Just use caution-any increase in pain or soreness that persists into the next day or causes a change in gait is a sign to pull back!
What can be done to prevent calf strains?
Although some risk factors for calf strains cannot be changed, others can be addressed in order to decrease the chances of this injury. Make sure to properly work into activity! Simple light movement to get blood flowing and loosen tissues will do. Using tools such as foam rollers and percussion guns on the calves prior to activity can be useful, as they increase ankle dorsiflexion range of motion without impacting muscle strength. Fatigued muscles are also more prone to strains, so athletes may want to try to avoid common mechanisms of calf strains (running uphill, sprinting, jumping) later in workouts. Athletes with a history of calf strains should likely avoid forefoot strike patterns and low drop shoes. Finally, strengthen those calves! They’re a main mover in running, so loading up calf raises and making sure they can withstand the demands of triathlon is key.
Jennie Hansen is a physical therapist, Ironman champion, and USAT Level 1 triathlon coach with QT2 systems. Hansen has a background as a collegiate and professional runner, as well as a number of professional triathlon podiums. She has been in the sport for over a decade.