What Happens When You Stretch

"When the muscle is stretched, so is the muscle spindle (aka intrafusal fibers). The muscle spindle records the length (and how fast) and sends signals to the spine which convey this information. This triggers the stretch reflex, or myotatic reflex, which attempts to resist the muscle length by causing the stretched muscle to contract. This basic function of the muscle fiber helps to maintain muscle tone and to protect the body from injury"
--I thought this quote was interesting because it says that the signals are sent to the spine. I'm not really sure why it is sent there. One of the reasons why we hold a stretch for a long time is because we need the muscle spindle to become accustomed to the new length so it stops sending signals.

"The static component of the stretch reflex persists as long as the muscle is being stretched. The dynamic component of the stretch reflex (which can be very powerful) lasts only for a moment and is in response to the initial sudden increase in muscle length."
-The static component is also known as the nuclear chain fibers, and the nuclear bad fibers are responsible for the dynamic component. Both of these are the two kinds of intrafusal muscle fibers.

"When muscles contract (possibly due to the stretch reflex), they produce tension at the point where the muscle is connected to the tendon, where the Golgi tendon is located."
- This is when the lengthening reaction occurs if the tension passes a certain point. The Golgi tendon is responsible for recording the tension.



Relate and Review:
Stretching starts when the sarcomere contracts which causes the areas between the thick and thin myofilaments to increase. When it stretches, the area decreases , and then the muscle fiber become longer. When you stretch the sarcomeres to their capacity, the connective tissue will then be able to stretch just a little bit further.