I often get questions from runners about what cross-training activities to do and some ask whether yoga is a good supplement to running. Yoga is excellent cross-training for runners because it improves flexibility and builds strength, which may help improve your running performance and prevent injuries. Doing yoga regularly also teaches you to breathe more deeply.
Check out Yoga Guide Ann's yoga stretches for runners that target the major muscle groups used when running.
I started yoga in high school, my cross country coach suggested it for tightness. 20 some odd years later I still run and have taught yoga 10 plus years!