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.
Achilles Tendon Lengthening may be performed if the tendon has been injured. Physical therapy may be necessary following Achilles tendon lengthening. Recovery time for Achilles tendon surgeries is usually four to six weeks in some kind of walking cast. A physical therapist may help someone who has had achilles tendon lengthening learn to bear weight on the leg.