Delivers electric impulses to tired and sore muscles. The muscles respond to the impulses by contracting and relaxing rhythmically, which sends soothing massage sensations to relieve muscle tension and soreness.Six massage modes with 10 intensity levels each provide various combinations of massage sensaations. The body tends to get accustomed to one particular sensation and will eventually stop responding to it, the different sensations available on this unit ensures that the body does not become desensitized.