Temperatures continue to drop as fall turns toward winter. For a lot of the runners out there, that means bundling up and continuing your craft. Unfortunately, colder temperatures can lead to shivering, increased muscle tone, and reduced blood flow to the extremities. This combination creates a perfect environment for muscle or tendon injury.

One of the most common running injuries is a strain to the calf or Achilles tendon. There are numerous reasons that a muscle can ultimately be injured while running, but important factors to consider are the warm-up and cool-down phases, as well as the length and strength of the muscle-tendon complex. To reduce the risk of injury this winter, we will take a moment to address each of these areas.

Figure 1A cold muscle does not have the same ability to stretch or accept load as a warm muscle. With a low ambient temperature, the warm-up phase becomes even more crucial to provide the body time to re-direct blood-flow and heat up the working muscles. The warm-up should consist of gentle dynamic exercises to mildly stress all of the muscles about to be used. Examples include gentle skipping, lunges, butt kicks, and side shuffles. Specifically for the calf and Achilles tendon, a combination of toe walking (Fig. 1) and/or double-leg heel raises should be performed prior to each run.

Cooling down is another area that becomes more critical in cold environments. The goal of the cool-down is to gradually return the body’s systems toward resting state and prevent reactive muscle tightening. Simply walking or slow jogging the final few minutes is typically adequate to allow heart rate to return to baseline. As in the warm-up, gentle dynamic exercises can also be of benefit at this time. After the heart rate has stabilized is an excellent time to perform static stretching to warm and flex muscle tissue.

Maintaining good calf length is crucial to avoiding injury and dysfunction. There are two primary muscles that make up the “calf” – the gastrocnemius and soleus. Only the gastrocnemius crosses the knee joint. This is important for stretching, as it needs to be performed with both a straight and bent knee to effectively stretch both muscles (Figs. 2 and 3). All stretches should be held for 30-60 seconds and repeat 2-3 times per muscle. As stated previously, static stretching should not be performed prior to running or competitive events. When performed prior to activity, stretching has actually been shown to reduce strength and performance.
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Having a “strong” calf is another crucial element to avoiding a strain to the calf or Achilles. However, being “strong” is not just about bulk and generating force. The muscle needs to be trained in the same manner that it will be stressed. In running that primarily includes eccentric loading (working while lengthening), high speed, and numerous repetitions. Two great ways to prepare the calf for running are eccentric heel raises and rapid single-leg heel raises (Figs. 4 and 5).
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