In the world that we live in today, consumers expect an all-around yet personalised service when it comes to the subject of wellness. It's debatable whether a personal trainer can stay relevant with only a trainer certification. More certifications, such as nutrition could provide a strategic advantage.

Specialisation is usually a good thing, but it also depends on your niche and how the market is evolving. You can have other skills in your toolbox and specialise in one area. It doesn't always have to be one or the other. You can do both.