Okay, so here's another Cross-fitter - 73 years old and proving once again that age is not a limiting factor if you have the determination to work at your fitness.
We don't know enough about CrossFit to say it is or it isn't the best way to get or keep fit, but for those who are adherents of the discipline it certainly does appear to provide them with the necessary motivation. At SGSC, it's the lure of being able to go out and do our sports that provides the motivation to continually go into the gym and work at our fitness. CrossFit sees itself as a sport in itself, and it appears that the competitive aspect to the training seems to be part of what motivates people. Perhaps CrossFit attracts people for whom competition is a motivating factor. At any rate, it seems as though all the competitiveness is about each person doing better and being better.
What is the most important aspect of training is consistency, and the kind of enthusiasm that CrossFitters appear to feel is absolutely necessary to be able to do the work.
So whether it's CrossFit, or another way of training, if you want to make progress - and progress and improvement at any age is possible - then consistency is the key.