When people do strength training, the outer calf muscle grows more than the inner calf muscles, no matter how they lift weights. This shows that some muscles naturally grow faster than others.

After eight weeks of strength training, different calf muscles grow at the same rate regardless of whether they are made up of slow-twitch or mixed muscle fibers. This means you don't need to change your workout routine based on your muscle fiber type to get the best results.

Different types of muscle fibers in your calf muscles don't affect how much they grow from lifting heavy or light weights, because both the mostly slow-twitch and mixed fiber muscles grew about the same with both types of 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.

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.

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.