A climber needs to consult with an expert when choosing and fitting harnesses for rock climbing. Different harnesses have different uses and features. Learn how to use a harness for rock climbing in this climbing video tutorial. Take action: use a harness, go with a trusted partner, and adjust the harness accordingly. Josh, the instructor in this how-to video from Live Strong, is an avid climber that resides off the coast in central California. He has managed for a mountaineering sports company for several years and loves the sport.