Any reputable personal trainer Fitzrovia » clients work with should hold at minimum a Level 3 Personal Training qualification, which is the UK industry standard for one-to-one coaching. Beyond that, look for additional certifications relevant to your specific goals — whether that's sports conditioning, pre- and postnatal training, nutrition coaching, rehabilitation, or performance optimisation. REPs (Register of Exercise Professionals) or CIMSPA membership gives you additional assurance that a trainer is committed to continuing professional development and is held to a recognised code of practice. It's a small thing to check and worth doing before you commit to anyone.