Doing calf raises while standing up with your knees straight builds more calf muscle than doing them while sitting down with your knees bent. Research shows that keeping your legs straight during the exercise leads to much bigger muscle growth over a few months.

Doing calf exercises while standing up builds more muscle in your lower legs than doing them while sitting down. Over three months, standing workouts can increase calf muscle size by about 10 to 12 percent, while sitting barely changes it at all.

Working your muscles while they are fully stretched builds more muscle than working them while they are shortened. This stretching advantage is especially noticeable in muscles that cross two joints, like the back of your lower leg, but doesn't seem to matter for muscles that only cross one joint.

Doing calf raises while standing builds more calf muscle than doing them while sitting. This happens because changing the angle of your knee changes how much your calf muscles grow, making standing calf raises much more effective for building size.

Building muscle works best when you stretch it out during your exercises. For example, doing standing calf raises stretches the calf muscle more than seated ones, which leads to bigger muscle growth.

Doing calf raises with your knees bent for 12 weeks doesn't seem to build much calf muscle, even if you train just as hard as you would for other muscles. This suggests that working your calves while they're shortened might not be the best way to make them grow.