popping hips? help

I have been taking kickboxing a few short weeks and have noticed something. In the begining of training when doing my dynamic stretches for my Gluteals, adductors, I stand on one leg and raise myleg to the side, knee straight as high as I can and back down. My problem is when I reach the max height with my leg my hip gives a good pop, sometimes on the way back down as well. It doesnt hurt at all but is quite unnerving. Like I said I am quite new to it all and I want to know if this could be cause I have weak hip joints, how to strengthen, is it normal etc. In the gym they say it will go away, anything to make it go away quicker?

Low hip stretching in a sitting position. Sit on the floor and spread your legs apart as far as possible. Alternating from one leg to the other, hold your foot with the same side hand while simultaneously touching your head to the knee of the leg.
Another good stretch is to lie on your side and grab the top leg with the opposite hand just above the ankle. Pull the leg up as high to the side as you can and stretch while keeping the other arm stretched out flat to the other side. This stretch is really good for releasing tension built up in the hips.
Since this is a nutrition post you could also
try calcium +D vitamin supplement. The amino acid proline is also reported to aid in the production and repair of collagen, cartilage, and other connective tissue.

Whew. I'm glad I'm not the only one.