No sex before a sporting event is a “rule” mainly found in the fight game, most notably publicised by Muhammed Ali. There’s no physiological evidence that rumpy pumpy would make a difference to athletic performance, it might actually increase testosterone instead of decrease it (which is also part of the “theory”).
In any case spending 6 weeks away from the distractions of dealing with women will help a fighter focus on his training, and not getting his end away will probably help make him aggressive.
So seeing as your just fannying about a field on a bike, I say crack on. Be sure to do her up the wrong un.