As an aside to this conversation (which I think is possibly close to going very off topic and becoming a crash course in sports psychology), I think there is also an interesting angle in terms of the contribution of the parent. I am using the parent example, as it is the one with which I am most familiar, but it does apply to other influential characters.
My son is ten years old. He has been skating since the end of December last year, after we both decided to learn to skate in order to play ice hockey. We have both followed very different journeys, summarised as follows :-
Myself : Started learn to play hockey sessions within a week or two of learning skating. I am quite a sensitive soul, despite having been in positions of authority in the past, but over the years have developed a much thicker skin and learned to cope with people fairly well. I'm not a very social creature, but I am friendly to others. My skating is progressing slowly, I get the ice time that I can, but like many others, I have to work for a living, and so my ice time is nowhere near as much as I would like. My skating coaches have been very helpful, supportive, and friendly. My ice hockey coaches, for the most part, have been a lot more abrasive, as you'd expect, but they have also been supportive, constructive, and helpful. It's like skating in two different worlds, but because of the contexts in which they are employed, both work within those contexts. If my LTS coach taught hockey, she would never maintain control. If my hockey coaches taught LTS, then within that context, they would probably be accused of being too aggressive or harsh.
My son : Has, as most kids do, picked up skating like a duck to water and has left me in his tracks. He progresses at an astronomical level. I have made it clear to him, from the very start, that he is under no obligation to do this. I want him to do it because he wants to do it, not because he thinks I want him to do it. As a result, the only pressure really comes from his skating and hockey coaches. His skating coach is excellent, and has a reputation as a very good kids coach, his hockey coaches are all seasoned hockey players, and also have excellent skills at dealing with the children on the ice. My son loves playing hockey, and is aiming to get into the local academy. I have encouraged him by telling him to just keep on doing what he's doing, and to enjoy the journey.
Not many weeks go by, where I don't see certain parents pushing their kids (and in many cases physically, not metaphorically) on the ice, barking orders at them, telling them off for wanting a break, or for wanting to play around instead of practicing hockey drills (I am , by the way, talking about public skate sessions at which this happens, not hockey sessions). A lot of these parents are living vicariously, through their childrens achievements, to either rekindle or make up for the parents success or lack thereof. I have seen children sitting crying on the ice, skating in tears, and generally miserable as a result of the constant barrage of 'harder, faster, better'. That isn't going to be my son.
My cousins husband is football mad. Throughout their lives, his two sons had football pushed down their throats. Finished school? Football practice in the garden. Weekends? Football games & football practice. It was always football, football, football. They have now grown up into teenagers, and what has happened? They have both turned their backs on football. It wasn't their choice to play, but rather their fathers insistence that they do.
My son said to me the other weekend, he wants to be a professional hockey player, so I can be proud of him. I replied 'just be a good person, and live a happy life, that's all I need to be proud'. Until he skated, my son wasn't particularly sporty, and I wasn't going to push him into a particular sport of my choosing. It had to be his choice, his sport. We just had to find that sport.
I have read of professional top-of-their-class sportsmen that have it all, the championships, the fame, the money, and yet they have resented their parents for robbing them of a childhood. That isn't going to be my son.
Don't get this out of context, I am in no way criticising other posters parenting skills, heaven knows I'm in no position, nor have any right, to do so. But it could be that children brought up with 'sporty go-getter' parents need a different style of coaching than those that have been bought up in more, dare I say relaxed, environs?