So far, the best muscle-powered solution is the climbing skin, simply a furry strip of fabric attached to the bottom of the ski. The fur naps to the rear, thus sliding forward and resisting backward movement. They're called skins because the first, invented more than 500 years ago by Northern Europeans, were merely strips of animal pelt lashed to their planks. Today's skins attach via adhesive or straps. Strap-ons interfere with your edges, snow can build up between the ski and skin, and frequently lack a dependable attachment system.
Skins come with different pelts.
Nylon is stronger and climbs better, and is your best choice for mountaineering. Most ski crampons lift up and down with your bindings, others stay fixed to your ski. Get down Skiing can be an exquisite sport, but only if you avoid mashed cartilage and shredded ligaments. The key to safe skiing is staying on your feet and being conservative. It takes several years, with many days on snow, for the average athlete to become a competent downhill skier.