If we are dancing tranquilly, with no acceleration or drama, we may relax the muscles between movements. But when we create an unusual change of direction or if we are dancing very fast or making very big or very slow movements, we use conservation of co-contraction to hold on to the power of one movement into the next.
If your body is compromised (extension of hip joint of weight-bearing leg in front of rib cage or internal rotation of legs) you will not be able to maintain muscle activation and will have to build it again.
