Describe How Muscles Function

The skeletal muscles of the body provide the force needed to move the bones of the skeleton in a large variety of actions. The muscles are arranged in a way that allows them to work in pairs. For example, when we bend our arms at the elbow to curl a dumbell the bicep acts as the agonist (main force providing muscle) and contracts to pull the radius and ulna of the forearm towards the humerus of the upper arm (this action is flexion). At the same time to allow this to happen the tricep at the back of the upper arm relaxes and lengthens to allow the arm to flex. http://www.peworld.org/anatomy/muscles.htm