Muscle stretch receptors and tendon streth receptors report to the cns muscles reflex why do tendons relax?

Its a balancing act- Muscle stretch receptors will cause contraction to keep the muscle from being damage by over-stretching. It takes a fairly large amount of muscle tension to cause significant stretch in the tendons, though-so when the tendon stretch receptor are activated, it means the muscle is pulling extremely hard on the tendon, which could lead to tendon and joint damage-thus then there is a signal to back off. In the end, the body decides it is better to have a torn muscle than to damage the joint itself- So, a little muscle stretch, like during sports, the body contracts the muscle to protect it. But, if the tension goes up too much- A lot of tension on the joint-puts the joint at risk now, which is harder to heal and a more damaging injury than a muscle tear, so the body relaxes the muscle- Hey, you got a groin pull-ouch, a few weeks off, you're ok- But tear up the knee joint, or pop out your hip-thats a long-term problem.