The peroneus longus muscle is located on the outside of your calf and runs from the head of the fibula to the first metatarsal in your foot. Along with turning your foot out to the side, the peroneus longus aids in ankle stability. When properly strengthened, the muscle can help you to be more balanced and agile on your feet.
Normally utilized to work your calves and ankles, calf raises can help to strengthen your peroneus longus. Stand tall with your feet hip-width apart, stomach pulled in and shoulders sliding down your back. Place your hands on a wall or chair for stability if necessary. Press through your toes to lift your heels off of the ground as high as possible. Lift your heels straight up and avoid any rotation in your feet or ankles. Hold the lift for one count and return to starting position.
Once you have mastered the basic calf raise, consider performing variations to increase the challenge. Single leg raises are performed with one leg lifted in the air. Stand on a step for elevated calf raises, which allows your heel to drop below floor level for a calf and ankle stretch. Angled calf raises, with your toes turned out by 25 to 30 degrees, can help you isolate the peroneus longus. Perform calf raises two to three times per week. Aim for three sets of eight to 12 repetitions per workout.