Endorphins.
muscles contract and relax by bring about movements.
They contract and relax
Muscles contract and relax to move a joint. ... Muscles contract at a constant rate. Muscles contract and relax to move a joint.
When you Bend your Leg your hamstring contracts and your quadriceps relax
Muscles contain certain proteins called contractile proteins which enable it to contract and relax to bring about movements.
Contract and Relax
The internal intercostal muscles relax and the external intercostal muscles contract, pulling the ribcage upwards and outwards.
Medicinal cannabis causes the muscular system in the human body to contract or relax. Try it :)
Do you mean "contract". Well, when muscles contract they get shorter and fatter. When they relax they get longer and thinner.
Skeletal muscles .
Muscles.
biceps and triceps respectively