Depends which bones
When they contract
When muscles move, they produce body heat.
Muscles contract and relax to pull/push
sarcomere's are the functional unit of a muscle which contract and make muscles shorter which then cause bones to move.
smooth muscles
Muscles and tendons move bones at the joints. You can not actually "move bones" on your own, rather you can only contract and relax certain muscles and tendons specifically told to listen to you.
The way the muscles are attached to the bones is what facilitates locomotion. The muscles contract which makes the bones move and creates locomotion.
with a lot of help you need muscles to pull on bones so that you can move
All muscles can move, but only skeletal muscles are voluntary. The cardiac and the smooth muscles cannot be moved by your will, but skeletal muscles can be.
one muscle to contract and the other muscle to retract
Muscles, tendons, ligaments and joints all work together to produce movement due to the fact that they are all attached. As the muscles, tendons, and ligaments expand and contract they pull the bones of the joint allowing the joint to move.
Your bones are solid and fixed - they cannot move by themselves because they have no flexibility. Your muscles are used to move your bones because each muscle can contract or relax - get shorter or longer - and therefore cause the bones to move.