You're careening down the singletrack, dodging obstacles, banking turns; your adrenaline's pumping...remind you of anything? Bike descents have much in common with skiing. "When going downhill, you develop the visual-mental skills you need when you're skiing fast-seeing and reacting quickly and handling adverse situations," says backcountry skier Robert Al-Chokhachy. Like ex-World Cupper Heidi Voelker (shown here on Moab's Slickrock Trail), keep your gaze 15 feet ahead as you would if you were skiing through a mogul field. Uphills build quadriceps and hamstrings as well as abs and back muscles. To up the strength component, do 60-second sprint intervals.