Relaxation in a spin class? Unheard of? Nope. Monday’s spin class instructor at Revolve Fitness in Union Square kept encouraging us to relax. Throughout the class, I could hear relax your shoulders, relax your arms, relax your fingers. One would think that the word relax in a cycling room with dark lighting and pumping music don’t mix. Add to that the typical shouted words of encouragement “don’t give up” and the dreaded “ACCELERATE.” Safe to say, the word relax was unusual but very well received.