Which of the following muscles when contracting would not contribute to forced expiration when doing a dead lift exercise? diaphragm. rectus abdominus. external obliques. internal intercostals.

The muscle that would not contribute to forced expiration when doing a dead lift exercise is the diaphragm.

Here's why:

1. The diaphragm is the primary muscle used for breathing. It contracts during inhalation, which allows the lungs to expand and fill with air.

2. During forced expiration, such as when lifting a heavy weight, the diaphragm relaxes and the other muscles (rectus abdominus, external obliques, and internal intercostals) contract.

3. The contraction of these muscles increases the pressure in the thoracic cavity, forcing air out of the lungs.

4. Therefore, the diaphragm does not contribute to forced expiration during a dead lift exercise. It is the other muscles that do the work in this case.