Good news

Stretching is key to good flexibilty - more so after a workout than before. Core strength can also go a long way in preventing back pain. Here are 2 links to injury prevention guides. The first one has strengthening exercises as well as a stretching guide (a foam roller is a great tool to use). The second one is a core strength guide. Injury Prevention for Runners: http://www.smiweb.org/massage/downloads/runners.pdf Core Strength Guide: http://www.smiweb.org/massage/downloads/core.pdf Good luck!