I am a high school senior who has run since middle school. I have gotten continuous stress fractures since freshman year and they havent ever seemed to heal. I should be a top runner in the state but due to injuries, cannot be. I decided to start cycling to stay in shape and for something endurance related to do since I cant run...I got my bike saturday and rode 10 miles then and 20 yesterday and about 10 today on the road and 10 on the trainer which was very tough. I dont know much about the sport but I was wondering if there is any tips or anything I should know. I got a Specialized Dolce road bike...and I have been averaging about 16-18 mph on flats. Tell me whatever you think I should know! Thanks.