It fits very well and even yet with enough excess material in length for the joint movement. It conforms to the back and fits very snug, I got a size large and it was perfect for me. Not too tight and not too loose, it's literally perfect.
the body suit fit perfectly to me !! it hugs my body just right. I am also a very small person (5'2 and 92 pounds) and bought a size small so please take those aspects into consideration when looking at sizing. the material feels light and almost weightless !!