All our changes are to adapt to our environment.

Marathon runners must be very thin and light. Sumo wrestlers must be heavy.

The work on the construction site will not be particularly heavy, but it will take a day, so the muscles of the body are endurance muscles. Endurance muscle is small in size but strong in endurance, a bit like a long-distance runner. People in the gym build big muscles just to look good. Practice a little more explosive muscles. Just like a 100-meter athlete