While plenty of runners never break out a pair of poles, they can be a big help when it comes to navigating efficiently up and down steep terrain. When used properly, they can increase propulsion going uphill, more evenly distribute the impact from running downhill, and keep you steady on tricky, off-camber surfaces. So in part nine of our Trail Running 101 series, we offer some tips on how (and when) to wield them like a pro.