Flexibility a must. If tournaments are allowed, generally the art is sport in nature. Flexibility a must for most systems. Good art for most ages, not good for some as it is best for smaller persons, works well into old age. Good for, depending on style, self defense and tournaments.
Some styles work well into old age.
Some of the very low stances are, well painful at times. Flexibility a must. Generally No striking. Not for tournaments. Works very well into old age.