forearm and upper arm muscles.
Move your arm in circles
To improve arm strength and flexibility, aim to do 15-20 arm circles in each direction daily.
There is not a single muscle that rotates the upper arm. The name of the muscle that contributes in rotation of the upper arm is deltoid muscle.
The brachialis is a muscle in the upper arm that flexes the elbow joint.
What are the tendon in your arm?
While one muscle contracts, the other muscle in the pair returns to its original length. The main muscle that bends your upper arm is called the Biceps brachii. The action is called flexion at the elbow. This muscle is on the "front" of the arm. The muscle that acts against this one is called the Triceps brachii. Its' action is extension at the elbow. This muscle is on the "back" of the arm. See the link below:
no
Your arm uses its bicep and tricep muscle to move. Muscles can only contract so they have to work in pairs. Ex. Bicep and tricep One muscle contract, the other relaxes
A muscle doesn't rotate the shoulder. The ligaments that connect your shoulder blade to your arm, to your rib cage all work in a ball and socket type of way allowing you to rotate your arm 360o.
where you bored when you posted this question or have you pop you muscle in you left arm
Deltoid