With the forces distributed properly across a harness, rather than on a make shift restraint, like a 1/2" wide hem of your shorts or the cuff of a cotton glove, you would be surprised at how much force and how violent a fall you can survive, provided the anchor points hold you. Iíve been out rock climbing and fallen 20-30' only to be caught up by my harness and gotten out of it with little more that some sore muscles and some bruising where the harness was.
Most harnesses will spread the force out over a fairly large area of your body. Be aware that some harness/PFD combinations are not meant for all people to use. The ones commonly found at West Marine, like their 4000 series aren't for use by people shorter than 5' 8" or so.
Point is is didnt break did it....