A slap on the back is more painful than a pat because triggers?

A slap on the back is more painful than a pat because it triggers a stretch reflex.

When you are slapped on the back, the force of the slap causes your muscles to contract reflexively. This reflex is called the myotatic reflex, or stretch reflex. The stretch reflex is a protective mechanism that helps to prevent damage to your muscles and joints.

The myotatic reflex works by activating the stretch receptors in your muscles. These receptors are located in the muscle spindles, which are small structures that are embedded in the muscle tissue. When the muscle is stretched, the stretch receptors send signals to the spinal cord. The spinal cord then sends signals back to the muscles, causing them to contract.

The stretch reflex is very sensitive, and it can be triggered by even a slight stretch of the muscle. This is why a slap on the back, which causes a sudden and forceful stretch of the muscles, can be so painful.

In contrast, a pat on the back does not usually cause a stretch reflex because the force of the pat is not as great. This is why a pat on the back is not as painful as a slap on the back.