Thank you for sharing your experience. The first step would simply be to collect anecdotal experience to establish that at least for some people, strenuous exercise had a beneficial effect after TBI. Then probably animal models could determine whether this is possibly a more general phenomenon, and what parameters (duration, intensity) seem to matter. Only then could cautious trials be performed in people. But there is a big pool of professional athletes in contact sports, many of whom would jump (or run, or bike) at the chance to get back to their sport more quickly, if it could be established that you can do so quickly.