http://kardysfitness.com/category/butt-legs- You can use this workout as a leg warm up and maybe tag it onto the end of a general warm here http://kardysfitness.com/category/warm-up. The choice is yours . .
Warming up with simple leg swings is super effective way to improve flexibility and mobility and is what is know as a dynamic movement as it really does target the muscles responsible for a lot of leg actions and these do include the hamstrings.
Lets face it dancers have been doing leg swings as an effective exercise for years and they have the most amazing flexibility. Do you agree?
If you can get your legs swinging and repeat the exercise in a plentiful manner you will see benefits in hip and leg muscles that will give you movement that you may have lost through just our daily activiities which do include very static sitting postures as we work and drive and watch TV in sitting positions.
If you want to see more hamstring exercises head on over to http://intra-action.com/types-of-stretches/hamstring-stretches
You will be amazed at how you can stretch your hamstrings further.