Is it fair to say that one needs frequent coaching and good weekly competition to reach the top level in squash? I wonder how little kids who pick up the game are able to reach A level in a few years, yet club players who play the game for a decade can not move up more than a level? When I talk to these kids they all seem to have good coaching. But the club players also take lessons so how come they don't improve as fast as these kids?

Juniors improve faster not just with good coaching, but also because they grow and get stronger. So naturally the older they get, they will be faster and stronger making them better players quicker than an adult. Adult players are already fully grown so thier improvement is limited to what they can learn technically and tactically.

It's down to neural plasticity. As an adult your neural pathways are fairly well established and they have less 'plasticity', so it is harder for and old dog to learn new tricks.

In children, the brain can alter the body's response to an external stimulus i.e. a moving ball much more quickly.