When you point your toes while keeping your knee straight, your inner calf muscle works much harder than the muscles around your shin and ankle. This happens because straightening your knee naturally changes how your body activates different leg muscles during exercises.

When you do calf exercises like heel raises, the electrical activity in the outer part of your calf muscle stays about the same no matter how bent your knee is. This is different from the inner calf muscles, which change their activity depending on your knee angle.

Bending your knee changes which calf muscle does more work when you push off the ground. Straight legs make the outer calf muscle work harder, while bent knees shift the effort to the deeper calf muscle.

When you do light calf raises with your knees straight, the exercise mainly works the outer and back parts of your lower leg muscles while leaving the deeper calf and shin muscles mostly untouched. This shows that keeping your knees straight during light resistance training specifically targets the more superficial muscles in your calves.

Your calf muscle is strongest at pushing off or bending your knee when your leg is completely straight. As you bend your knee more, it gets much weaker because the muscle becomes too shortened to generate full force.

Bending your knee to 90 degrees makes your soleus calf muscle work better than keeping it completely straight. This happens because of how the muscle is built and how its length changes with different knee angles. So, if you want to activate this muscle most effectively during movements like calf raises, keeping a slight bend in your knee is best.