Explanation of the StretchReflex
Explanation of the Stretch Reflex
When a muscle is stretched (lengthened), sensory
organs in the tendon send a signal to the spinal cord which causes a reflex contraction (shortening) of the muscle. This reflex restricts initial efforts at stretching; however, if the stretch is maintained for 10- 30 seconds, the stretch reflex will subside and permit gains.
This slide illustrates the mechanism of the stretch reflex. This reflex is important to understand because it explains why it is important to hold a stretch for an extended period of time (10-30 seconds). Attempts to stretch for shorter durations are limited by the opposing action of the stretch reflex.
Image reproduced with permission from Hole’s Anatomy and Physiology (Shiers, Butler and Lewis) - McGraw Hill Publishers