Hey guys, I need Help. Im a little guy 5'2 and I aint well built in any way. I train Thai with a few buddies. I weigh around 8 and a half stone and the guys I train with are between 15 and 18 stone. I can hold my own with any of them sparring cos of my speed. But one thing really kills me, when we do padwork I will hold the pad against my leg for them to low kick. Five days ago we did a combo where it ended with a Low kick. I held It so two of them performed the combo 1 time each and I had to stop because of the pain in my thigh. My leg is still sore. Is there any way of toughening up my legs at all. Its not my shins, its the side of my thighs that are in agony.
We try to practice fast combos or else I would just double up the pad.
any advice would be greatly appreciated.

I never really noticed if I do or don't. I think I probably do because I know the pain is on its way, hee hee. I'll try loosening up when they kick it. Thanks man!
Is there any way I should be angling my leg in order to make it easier or foot positioning like up on the ball of my foot or keeping the foot flat?