Spring washers, sometimes called disc springs, are a subtype of washers. They lend their mechanical capabilities to the unique profile of the material: when subject to a load, the irregularities of the washer compress with a proportionate resistance to return to their predeflected shape.
You should never stretch a pulled muscle to the point of pain or you risk re-injuring it. Do not overstretch the pulled muscles. Too much stretching can retear injured muscle fibers. Gently stretching a pulled muscle may relax the surrounding muscle fibers, which may be tight in response to the injury.
When a tendon stretches due to muscle contraction, the GTO's in the tendon sense the stretch and send a signal to the spinal cord which relaxes the muscle so that it doesn't tear the tendon. Golgi tendon organ reflex or tendon reflex; it prevents the TENDON from being torn due to an overly contracting muscle.