Contrary to the popular belief that martial arts training in general is always healthful and great for your body, certain practices can have deleterious effects over time. One of my older Ving Tsun "nephews" in Texas was once a nationally ranked TKD champion. Thanks to the effects of his former dedication to that discipline he now trains VT on two artificial knees. VT/WT/WC by contrast is pretty easy on the body as the years go by, but as I move through my mid fifties, I'm beginning to wonder about the long term effects of certain aspects of my training. For example, I like hitting the wall bag. Mine is just filled with rice and beans, so it's not that hard, and it's a great way to let off steam. On the other hand, how good can it be for your knuckles to pound away thousands of times against a dense, coarse cotton bag? The same goes for working too hard against the dummy and so forth. In short, without being wimps, should we start modifying our training regimen when we get past a certain age?