The calves, known technically as the gastrocnemius muscles, are composed of two different heads: the medial head makes up the inner part of the calf; the lateral head makes up the outer part. Both heads converge onto the Achilles tendon and work together to extend the foot at the ankle, such as during standing calf raises. New research from Armstrong Atlantic State University (Savannah, Georgia) shows that you can focus more on one head by simply turning your toes in or out. Weight-trained subjects did 10 reps of standing calf raises with their toes pointed straight ahead, turned in or turned out, while scientists measured the muscle activity of the gastrocnemius heads. On calf raises with toes pointed in, the muscle activity of the outer calves was significantly greater than the inner head. Conversely, on calf raises with toes pointed out, the muscle activity of the inner calves was greater than the outer calves. If one area of your calves lags behind the other, focus more on that head by simply changing your foot position during calf raises.