If your calves are sore immediately following your run, it's a good sign that you need to correct your running form. Poor form and the wrong pair of running shoes can cause you to impact the wrong areas of your feet with every stride, putting a strain on your muscles and tendons and promoting the development of impact-related injuries. Diagnosing your pain is the first step to eliminating it, and adopting a more minimalist approach to running that embraces the most natural technique for your body can prevent injury in the first place.
Where It Hurts
Two major muscles in your calf are the most prone to strain. The larger muscle, the gastrocnemius, runs from the back of your knee to the middle of your calf. Partially underneath it, the smaller soleus muscle connects your achilles tendon to the calf. These muscles together generate the propulsive movement of your forefoot that you use in each of your strides. The gastrocnemius muscle is particularly susceptible to injury in runners and other athletes, since it's a fast-twitch muscle that crosses two joints, and is often involved in quick movements that can tear or strain the muscle.
Diagnosis: Calf Strain
Bryan J. Dixon of the Marquette Sports Medicine Institute says that differentiating the cause of strain in these two muscles is a key step in recovery and rehabilitation. Gastrocnemius injuries are significantly more common than soleus injuries because of the nature of the muscle contractions involved in running. Dixon recommends completely rehabilitating a sore muscle with stretching and prolonged rest to ensure that any injury is completely healed. Running on a sore muscle too soon can re-injure it and greatly prolong rehabilitation and recovery.
A calf strain is likely the result of overuse or an over-extension of the muscle, which can occur during your run. Potential calf injuries sustained from running can vary significantly, from muscle tears to fractures. Straining the Achilles tendon may also manifest as calf pain. If you're having trouble pinpointing the source of your particular soreness and it persists past several day's rest, consult your physician or a sports clinic to see if the issue may be more serious. Never run with pain, since there's a chance you could make a minor injury much worse. Some serious calf injuries, such as a bad microfracture, could require surgery before complete rehabilitation can be achieved.
Covering All Your Bases
If your soreness is prolonged or reoccurring, however, your stride and footwear should be checked to make sure you're following the most natural running technique. Minimalist footwear provides the most protection against calf injuries when paired with a forefoot strike, since the strengthened muscles will prevent strain and reduce impact. Minimalist footwear requires a substantial acclimation period on the scale of months, but the prevention of calf injury is one of many benefits provided by natural running.