Primarily, core and back muscles are activated together with muscles around the hip and shoulder joints. The effect will be stabilization of the upright posture.
The activation, originating in the vermis and nucleus fastigii, is mediated by the tractus reticulo-spinalis which, on its way down through the spinal cord on the origin side, emits a limited number of lateral branches to the opposite half of the spinal cord. The effect will be a certain activation of the musculature even on the opposite half of the body.