How do the muscles in your arm extend your arm outward?
◦ Some muscles in your arm relax and others contract, pulling the arm straight.
◦ The top half of your bicep wraps around underneath the elbow like a rope over a pulley. When it contracts, the arm is pulled out straight.
◦ The muscles in your arm push on the bones causing your arm to extend.
◦ The muscles in your arm relax and the tendons pull the arm straight.