Trainers.net is a great brandable keyword domain name for your business.
".net" domains can be associated with networks/communities. For example: a network of personal trainers.
In the european markets, trainers usually refers to athletic shoes. In most other markets the word trainers can be associated with the term "personal trainer".
Trainers.net can also be used for professional coaching services.
Activities, sports and health are a growing market across the world and many people look for good trainers in the various physical activities they want to try or excel at.
Exercise, sport specific, health and recovery training are all related areas where a trainer might be searched for.
Over the five years to 2020, revenue for the Personal Trainers industry is estimated to increase at an annualized rate of 2.4% to $10.4 billion, including a 1.4% increase in 2020 alone. Rising interest in personal fitness, partially prompted by worsening obesity trends, has resulted in strong demand for the industry's trainers. The industry still experiences competition from do-it-yourself fitness modes (such as exercise videos or running), which enable consumers to improve their health at a lower cost.