What happens to an arm and a leg when carrying a weight?

We are able to move, carry various objects and perform various actions due to the presence of muscle tissue. Muscles cover our bones and together with them form the musculoskeletal system. When we just move, the muscles in our lower limbs tense. When we are still carrying heavy things, the muscles of the arms and legs become more tense. They receive a greater flow of blood. Also, muscle fibers can break and this is a normal process, since on the basis of this, the muscles become larger in volume and stronger.