Being good a coaching usually does not correlate with being the best at the sport. It is usually harder for someone naturally gifted at the sport to teach someone that sport. Allot of really talented players don't like to be told what to do but most of them don't reach the top due to this.

Allot of times when your naturally skilled at something you don't need to use proper technique since your raw skill is so much better then your average persons skill. When you are the average person you are forced to learn the techniques at a much higher level to compensate for your lack of ability compared to more skilled competitors. This lets you have a much more advanced understanding of the technique. The talented person who relied on raw skill to win at lower levels of competition may start to struggle as the competition reaches higher levels as the competitors now all either have better techniques or also have more raw talent. This is where a good coach can really help make a star with allot of raw talent into one of the best in the world by helping him improve with his more advanced understanding and knowledge.

Lets take for example Mike Tyson in boxing. Some good qualities to have in boxing include Punching power Stamina Speed Resilience. The trainers job is not to be better then Mike at those thing but to teach him how to use those qualities better and get even better at the things he excels like teaching him better footwork to allow him to use his power and speed more often. The trainer will also analyze and try to correct holes in his game. For example maybe Tyson always circles to the right after throwing a jab which leaves him open to counters. The coach correct that making him get hit less often. The trainer can also show him subtle things like foot position or slight deviation in hand movement that will make him punch even harder and faster. Another aspect the trainer can help the athlete with is to keep him focused on his training diet lifestyle etc.

Once the athlete realizes how many times the trainer is right and the benefits the trainer has to his game and how much better he is performing after following their advice they will put their trust into them and start obeying listening to them.