Useful. In fact, many fitness methods can be learned through video, but the advantage of personal trainer is that it can teach one-on-one and correct the wrong movements or postures in time, so that the movements are in place and it is convenient to ask questions. Many times, we learn from the video, but we can't see our own actions, thinking that our actions are in place and correct. Actually, it's not. I think the biggest advantage of hiring a personal trainer is here, and it is usually a tailor-made plan.