My hip joints

Hi all
I am 52 and have been in the martial arts for a long time. I never was able to do a full split no matter what but I have noticed lately my hip joints are more painful and my roundhouse and side kicks don't go as high due to that. In reality I personally would not kick high and I have quite a lot of power in my low kicks, Groin and legs mostly.

I would like to be able to kick highr for the fun of it and I don't like to be limited anyway. Does anyone know of something, a stretching technique that works specifically in this area?

Thanks

You need to do some dynamic stretching. Just swing your leg up to a comfortable height, within your current range of motion. Do this 8-15 times, gradually increasing the height until you've reached your maximum extension, as determined by your curent level of flexibility. Be careful not to throw your leg up so it reaches its limit at momentum; you'll tear a muscle that way. Control the kick.
Do this to the front, back and side with both legs. Do it every morning upon waking, and at least once again during the day. The more often you do it, the quicker you'll progress