I think all of those ideas are good from Tex, jp, and Crash. I personally use a weighted vest from time to time too. And, yes, if you pack it full of weight right off the bat it will strain your knees...just like any other resistance exercise it takes some time to condition your muscles, ligaments, tendons, and joint structures. Most vests are adjustable. Mine is a 20 pounder; which can be adjusted from 1 to 20 pounds. However, gradually adding more weight in a vest can be a tremendous training aid. By weighing say 230 lbs you could make yourself weigh 250 lbs and burn loads more calories plus explosiveness etc. I really like the vests.
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