The cell is long because the , muscle needs to stretch and contract when you use that muscle. Therefore it needs to be long in order to stretch.
I stretch 30 seconds each muscle I've used in a particular exercise.
Apply heat, take ibuprofen, and stretch the muscle
the muscle spindle detects excessive stretch within the muscle , it response and makes the muscle contract
you run the risk of pulling a muscle and causing long term damage.
Your groin is being stretched.
there are multiple debates on this. my thoughts are that you stretch the muscle before an athletic event for 30 seconds
If you think about your mind as if it were a muscle, you can figure this out. If you stretch a muscle, it gets stronger. If you stretch your mind, you think of new things and your mind gets smarter.