A new article in NY Times Health suggests that teens going through a gawky phase are prone to injuries. Read it at http://well.blogs.nytimes.com/2011/04/20/sports-injuries-and-the-teenage-brain/?ref=health.
This is a phenomenon I have seen. I think this article, based on findings from a British Journal of Sports Medicine. Apparently, puberty helps stability, while developing children who have not yet begun puberty tend to be more awkward, have a somewhat impaired sense of self that affects balance. Part of this may be due to the fact that during puberty, our organs grow, and we generally begin to fill out. Another side effect is that if the child has poor body mechanics that are inherited, growth spurts will aggravate the problems, especially in girls as their hips become wider. This has been shown to be responsible for many knee problems in developing pubescent girls as they develop. Read the article, it is quite interesting.