What is a good warm up exercise for hips?

There are many ways to warm up your hips before activity. A kneeling or standing hip flexor stretch, for example, is a great static stretch that you can do to gain range of motion and help reduce the chances of injury if you are tight. I suggest that you do this stretch first and be sure to hold it for a minimum of 30 seconds each. After this stretch, you can go right in to a dynamic movement prep such as walking lunges with rotation. This exercise is a great way to stretch the hips while activating your quads and glutes. Try performing 15 reps on each side and make sure that you keep your front knee over your 2-3 toes and your abs in tight.
 

Here's how to do hip circles on your back to warm up hips:

Reps: 20 per leg
Sets: 1
Intensity: Light
Tempo: Slow and controlled
Rest: No rest needed

Starting position: Lie on your back with your left knee bent and the foot flat on the floor. Place a yoga strap over the foot of the right leg and extend it.

Movement: Point the toes of your right foot slightly toward the ceiling and slowly make 10 small circles to the right. Then make 10 small circles to the left. Repeat with the left leg.

Tips and techniques:

• Initiate the movement from the hip.
• Contract your abdominal muscles and be sure your back is touching the floor throughout.

Too hard? Make smaller circles to limit your range of motion.

Too easy? Make larger circles.