I live in central California, and I did a dumb thing a few nights ago in the cool weather at the track. After jogging five laps around the track, I decided to run my normal 5 x 100 meter and 5 x 200 meter sprints. On my last 200 meter sprint, I felt my hamstring pop with about 20 meters to go, so I quickly spotted. It has been about a week since I hurt my leg, and feel very little pain when walking around. I'm wondering how long I should rest it until I try playing singles? I really learned a good lesson about running in cool weather!