The fire hydrant exercise is great for increasing mobility and range of motion in the hips.
Start on the ground on all fours.
Knees need to be underneath the hips
Try to bring your heels up to your butt to engage hamstrings
Tip: Use a ball behind your knee to keep the hamstrings engaged
Lift your knee off the ground and make as large a circle as possible with your isolated leg.
Change the direction of the circular motion after 10-15 reps on each side.