 its just conditioning...
I would think that as long as you take it at a reasonable pace without trying to kill your shins, and as long as you don't take too much consistent damage, you should be fine. Of course the older you get, the more you'll have to adjust and slow it down. To be honest, I really am not familiar with any medical studies or research regarding this, but I'm often around some older practitioners who've spent years in serious thai training such as Kru Vut Kamnark and Guro Inosanto among others lesser known...their legs seem fine, or even in extremely good shape, for their age. I'm not too worried about it. At least that's my opinion. |