The problem could be caused by body temperature. Normal people start to shed body heat in preparation for sleeping. Serious physical activity in the 2 hours before bedtime mucks this up by generating a whole lot more. The trick is (following the logic) to dump body heat somehow. They are working on this with some insomniac patient groups who have been shown to not drop body heat like everybody else.

I used to have this problem getting to sleep after hockey too. In Dunedin I used to get round it by walking home in a t-shirt after hockey (air temp was probably about 4 degs centigrade). This might work well for people in the right sort of climate. Now I live in Sydney -forget about it. A cool shower might do it?