The muscles you use in a push-up are the chest, back, and triceps. Around the eyes (crow's feet)
pectoralis major
Deltoids, triceps and pectorals.
Your leg muscles work together to help you walk up stairs.
Muscles can only pull, so for joints that need to go both ways (like your elbow, up and down) you need one muscle to flex, one to extend. These are Flexors and Extensors, or can be called the Prime Mover and Antagonist. There's a third muscle which are grouped up as the synergists, which simply helps the Prime Mover do its job. For example, Lifting your leg up would be using the following: Quadriceps as the Prime Mover, Hamstring as the Antagonist, and your glutes as the synergist. Hope that helped! ^^
Agonistmuscles cause a movement to occur through their own contraction. [1] For example, the triceps brachii does during the up phase of a push-up (elbow extension). During the down phase of a push-up, the same triceps brachii actively controls elbow flexion while relaxing. It is still the agonist. While resisting gravity during relaxing, the triceps brachii is still the prime mover, or controller, of the joint action. For both of those movements the elbow flexor muscles are the antagonists. Agonists are also referred to, interchangeably, as "prime movers", since they are the muscles being considered that are primarily responsible for generating a specific movement. This term typically describes skeletal muscles.[2]
Pectoralis major, deltoid, triceps brachii, coracobrachialis, serratus anterior, external and internal obliques, rectus abdominis and the transverse abdominis are all used in push ups. The pectoralis major and the triceps are the prime movers.
The gluteal muscles and the quadriceps would be the muscle groups most likely used by the actors and dancers in the movie Step Up.
The prime mover for shoulder internal rotation is the subscapularis muscle, which is one of the four muscles that make up the rotator cuff. It originates on the subscapular fossa of the scapula and inserts on the lesser tubercle of the humerus. Contraction of the subscapularis muscle causes internal rotation of the shoulder joint.
Your pectoral muscle allows you to do a push up. When you do a push up you use your pectoral muscle, your tricep muscle, and you use your shoulder back at the rotator cuff.
The atissimus obrsi abdominals is the prime mover in a sit up.
The gluteus maximus is engaged eccentrically during hip extension when walking up stairs. This means the muscle is lengthening under tension to control the movement of the lower body and support the upward motion of the leg against gravity.
The squat works many muscles in the body in some form. The primary movers are the hamstrings, quads, and glutes. Assuming you are doing them correctly with your knees out and squatting below parallel, you should be using your hip adductors as well.