I usually wear Shock Absorber Ultimate Run bras but had been struggling to fasten them at the back due to a shoulder problem. I purchased two Infinity Power bras as they zip up the front and they are much easier to get on :) They are much easier to fasten than the M&S front-fastening sports bras I bought at the same time and it feels more supportive. It does squash your boobs together but you can't see your cleavage as it comes up quite high at the front. I bought the same size as I wear in Ultimate Run bras and I think it fits OK. The band sits slightly higher at the back but I'm not sure whether it's the design or the sizing. I might try going up a cup size and maybe down a band size if I buy another one. I had to adjust the shoulder strap to the shortest setting, but that's not a problem.