What Happens When You Stretch?

What does happen when you stretch?

"Just as the total strength of a contracting muscle is a result of the number of fibers contracting, the total length of a stretched muscle is a result of the number of fibers stretched-- the more fibers stretched, the more length developed by the muscle for a given stretch"

As the sarcomere of the muscle fibers contract, the area of thick and thin microfilaments that overlap decrease which is the result of a stretched muscle. A muscles ability to stretch does not matter how long the stretch is held, it all has to do with how many muscle microfibers were stretched.  This correlates with the quality over quantity. When muscles get longer due to prolonged stretching, the resistance is much lower which creates the length and therefore gives a better and more effective stretch.

"One of the reasons for holding a stretch for a prolonged period of time is that as you hold the muscle in a stretched position, the muscle spindle habituates and reduces its signaling. Gradually, you can train your stretch receptors to allow greater lengthening of the muscles"


When the muscle is stretched for a long time, the muscle fibers get comfortable being separated which is why there is less signaling and the receptors can begin growing longer. They grow because when they are stretched, they are capable of increasing the length of each muscle fiber over time. When a person begins to stretch themselves, their muscles may hurt a bit but by the end, they feel nothing. This is because the signaling of the muscle spindles is reduced.

"So, when a fast stretch is demanded of these fibers, the middle takes most of the stretch at first; then, as the outer-middle parts extend, the middle can shorten somewhat. So the nerve that senses stretching in these fibers fire rapidly with the onset of a fast stretch then slows as the middle section of the fiber is allowed to shorten again"

During a stretch such as a leg swing, the middle stretches the most at first but then the stretch carries towards the outer areas so that the middle is able to shorten which creates a greater stretch for the rest of the muscle. The nerves are working rapidly, unlike the static stretching which has the nerves slowly reduce causing less pain. With a "higher than normal" signaling, the length muscle will decrease in length.

Relate and Review:

Here the muscle is relaxed and contracted.
The increase is length between thick and thin
fibers makes it easier to stretch because
there is already a gap.

In this article, I learned about the ways in which the muscle stretches and the impacts that occur simultaneously. A muscle will stretch when the sarcomeres of the muscle fibers decrease the area of overlapping which creates an elongated muscle fiber. This forces the stretching of the connective tissue and the more it is stretched, the longer the muscle fibers become. Proprioceptors are the source of the perception of one's own body position and movement. There are 2 kinds of muscle fibers; intrafusal fibers which are also called muscle fibers and they are parallel to the extrafusal fibers. The muscle fibers are the primary proprioceptors. When extrafusal fibers lengthen so do the intrafusal fibers. Since there are 2 different types of stretching, there are 2 different types of muscle fibers that can be stretched. The nuclear chain fibers are for the static stretching and the nuclear bag fibers are responsible for the dynamic stretching. Nuclear bag fibers are more elastic and they are the fast stretch. The reciprocal inhibition is when the muscle relaxes which creates a better stretch.