Hi There. In terms of serious sports activities, none. However I did in fact play tennis and cricket. Tennis from about age 6-12. Cricket from about 15-18. However these were simlpy extramural school activites. The imbalances never showed up even in the initial years of gym training, till about 2 years ago.
Normal lunges were difficult - even with very light weight there was trouble balancing. I actually also tried DB step-ups: could only manage with very light weights - about 10kg/side. The back lunges felt best: not too akward, better balance, but still hitting the weaker muscles.
I will probably stick to them for now, but do thing like BW step-ups at home to build up the proper form before attempting heavy loads. Are there any other exercises you could suggest, either at home or gym, to strengthen the hip-flexors and upper quads (preferably something I can one-legged in order to help the imbalance).