I think genetics is a paramount concern when talking about competition or your own training. For example, two years ago I ran a marathon, training for about 6 months. My friend ran also, and his only training was smoking cigarettes - he did not run once. Yet he still ended up beating me! The physical differences along the genetic spectrum are tremendous. This is also a major concern for training. Different people have different capacities for stress. When formulating an exercise program, you should not base it on someone else's program. Some people might be able to work out 5 days a week, some may only be able to work out 2 days. Art has described the principles of EvFit. Everyone should adapt them to their own circumstances, and see how they work for them individually.