Tight hips and hamstrings are a common runner's complaint, and while doing some mountain climbers or jumping jacks is a great warmup before a run, they don't do much to slowly open up those tight areas. Here's a fun yoga move called Circling Three-Legged Dog that will loosen up tight hips and hamstrings while increasing circulation to the legs, ankles, and feet.
If you loved this move, here's another Down Dog variation called Down Dog to Tuck-Toe Up Dog, which is great for warming up the hamstrings, calves, lower back, and shoulders.