Músculos asombrosos

The video explains how skeletal muscles, attached to bones, enable movement by contracting and relaxing. Muscles work in pairs, as they can only pull, not push. For example, the bicep and tricep work together to move the arm, while the hamstring and quadriceps coordinate to move the leg. This cooperation allows for complex movements and highlights the importance of muscle pairs in the body.

What happens to the hamstring and quadriceps during leg movement?

Why are muscles that work alone considered useless?