What is a Strength Coach?
In the simplest terms, a strength coach is someone who helps improve your muscular strength. It may mean that you get bigger muscles, but it could also just mean that your muscles get stronger, without much change in size and composition.
That being said, not every strength coach is the same: some focus on muscle gains, others focus on functional movement, while others are merely personal trainers who focus on strength work. Your program will probably include some weight training, but your strength coach may prefer to use TRX-cables, kettlebells or even just your body weight in your program.