How Do Muscles Push?

Muscles themselves don't actually push; they pull. The illusion of pushing is created through the coordinated action of opposing muscle groups. When one muscle contracts (pulls), it moves a bone, and a second muscle, the antagonist, then contracts to return the bone to its original position. This interplay of pulling actions produces the appearance of pushing.

The foundation of muscle contraction is the sarcomere, containing the motor protein myosin. Myosin interacts with actin, another protein, causing the muscle to contract through a "grabbing and flexing" mechanism. When myosin releases actin, the muscle relaxes. (Reference: Sarcomere definition)

Think of your bicep and tricep muscles. To bend your arm (flexion), your bicep contracts, pulling your forearm towards your shoulder. To straighten your arm (extension), your tricep contracts, pulling your forearm back down. The bicep's pull appears as a "push" from the forearm's perspective. This principle applies to many body movements.

• Example 1: Push-ups: The pectoral muscles (chest) and triceps (back of upper arms) contract to push the body up. They are actually pulling your torso and arms closer together. Gravity then "pulls" you back down, initiating the next repetition. (References: Muscles worked in push-ups, Pushups - Physiopedia)
• Example 2: Bowel Movements: The rectum’s muscles contract to push stool outward, but this is actually pulling stool along and out of the rectum. The relaxation of the pelvic floor muscles also assists this process. (References: How bowel movements work, Bowel Function Anatomy)
• Example 3: Breathing: The diaphragm, a sheet-like muscle, contracts and moves downward. This is a pulling motion that increases the space in your chest cavity, causing your lungs to expand and pull in air. Exhalation involves the relaxation of the diaphragm and the contraction of other muscles, which push air out. (Reference: How the lungs work)

Muscles Work in Pairs

Muscles rarely work in isolation. They function in synergistic pairs, often referred to as agonist-antagonist pairs:

• Agonist: The muscle primarily responsible for a particular movement (the "prime mover").
• Antagonist: The muscle that opposes the agonist's action.

This coordinated action allows for controlled and precise movements. (Reference: Bones, Muscles, and Joints (for Teens) | Nemours KidsHealth)

While training near failure increases muscle growth (Reference: For Bigger Muscles Push Close to Failure, For Strength ... - FAU), it's crucial to remember this principle. Effective training incorporates both concentric (muscle shortening) and eccentric (muscle lengthening) contractions.