I’ve been hurt 2-3 times 1-6 weeks out from races. I always tried to maintain my fitness by getting on an Ellyptical Trainer. You can really grind away on those things and maintain some fitness. A person loses little fitness after a week off, so I always tried that first and if I had access got on something to grab a workout. I missed a decent portion of training this summer, but when I got on an old ten speed I put it in 10th gear and rode like a mad man for 10-20 miles each time. Sometimes twice a day.