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.
Heal Your Achilles Tendon Injury. Devices and exercises designed to stretch the Achilles will make your injury worse. Even though stretching may relieve the pain of the cramped tissue and feel like it helps, you may actually be reversing the healing process by tearing the Achilles Tendon further.