Push-ups are predominantly an isotonic exercise, but they also involve elements of isometric contraction. Let's delve into the mechanics of push-ups to understand why this is the case.

Isotonic exercises are those in which the muscle length changes during the movement, and the tension or force generated by the muscle varies. This type of exercise is characterized by the muscle's ability to generate force while it contracts and shortens (concentric contraction) or while it lengthens (eccentric contraction). During a push-up, the major muscles involved are the pectorals, triceps, and anterior deltoids. When you lower your body towards the ground (the eccentric phase), your muscles are lengthening under tension, and when you push your body up (the concentric phase), your muscles are shortening under tension.

Isometric exercises, on the other hand, involve muscle contraction where the muscle generates force without any change in the length of the muscle. This is often referred to as a static contraction. In the context of a push-up, isometric contractions can occur momentarily at the bottom of the movement, where you might hold the position for a brief period (known as a pause), or when you are at the top of the push-up and your muscles are still engaged to maintain the position.

Now, let's address the provided reference content:

- Synergist muscles are those that assist the primary muscles (agonists) in performing a movement. In the context of an overhead press, the triceps are the agonist, and the deltoids are the synergist. This information is relevant because it highlights the role of different muscle groups in compound exercises, which push-ups are a part of.

- The statement that "Examples of compound isotonic exercises include pushups, pull-ups, barbell presses, squats, lunges and dead lifts" is accurate. These exercises engage multiple muscle groups and involve movement at two or more joints, which is characteristic of compound movements.

In summary, while push-ups involve both isotonic and isometric elements, they are primarily classified as isotonic due to the significant change in muscle length that occurs during the movement. The push-up is a compound exercise that effectively targets the chest, triceps, and shoulders, with synergist muscles playing a supportive role.

Now, let's proceed with the translation into Chinese.

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Synergist muscles tend to be smaller than agonists. In overhead pressing exercises, the agonist is the triceps while the synergist is the deltoid. Examples of compound isotonic exercises include pushups, pull-ups, barbell presses, squats, lunges and dead lifts.Feb 4, 2011read more >>