After eight weeks of leg workouts, the outer calf muscle grows noticeably bigger than the inner calf muscles in beginners. This suggests that muscles made up of faster-twitch fibers are naturally better at getting bigger when you first start training.

If you do weight training for eight weeks, the outer part of your calf muscle tends to grow bigger than the inner calf and the deeper calf muscle. This happens because the outer calf has more fast-twitch fibers that are naturally better at building size.

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.

When you do resistance training, different parts of the same muscle group don't grow at the same rate. For example, the outer calf muscle tends to get bigger faster than the inner calf and deeper calf muscles, which suggests that how muscles are naturally built and activated matters more for growth than the exact workout routine you follow.

Doing specific calf exercises for nine weeks can make the calf muscles bigger, but exactly how much they grow depends on how you position your feet during the workout. This shows that small changes in your exercise form can target different parts of the muscle differently.

Even if you do a lot of leg workouts, your thigh muscles grow about the same amount whether you do 20 or 50 sets a week—just doing any consistent training makes them bigger.