First, the weird science. Every muscle movement you make has two parts: concentric, when the muscle shortens (think of a bicep curl, when you lift a weight to your shoulder) and eccentric, when the muscle lengthens (lowering the weight and straightening your arm). While the muscle contracts with each movement, the eccentric phase is a lot stronger and uses more power. That’s why many elite athletes concentrate on the eccentric part of an exercise during their training—like bending slowly when lowering the weight in a squat (eccentric), but standing up more quickly for the concentric part. The eccentric phase of a muscle contraction is when the muscle is doing the most work.
When you walk down a long, steep hill, you’re mainly making eccentric muscle contractions; the ones that help you stand up and resist gravity. You’re also resisting the force of your own body, which puts about three or four times the weight of your body on each leg with each step.
The quads are the main muscles resisting these forces when you walk downhill. It’s a down-and-dirty workout with two major benefits, and one major drawback. The first benefit is that we normally don’t get much eccentric movement in the thighs. Even on a treadmill incline, we’re running uphill, so a long downhill walk of eccentric movement will do an amazing job of correcting that imbalance and protecting your thigh muscles against injuries that often result from muscle imbalances.
The drawback comes from the fact that most of us are not accustomed to this more powerful type of quad contraction, so it rips the muscle fibers a little, just as any new exercise does. The result will be harmless pain, the good pain that comes when a muscle rebuilds by getting stronger to handle a higher load of stress. But the second benefit makes up for it: Once you take that long walk down, the muscles adjust. You can do it again, and the next time, you’ll feel no pain. The pain-free adjustment lasts for about six weeks to two months; if you don’t do another eccentric walk within that time, you’ll have to start all over.
One of the best places to walk down a mountain right now is The Canyons in Park City. Take the gondola up ($15), then ride the nearby High Meadow lift (free). At the top, you’ll see a plethora of paths for biking or hiking; easy terrain with a short walk down. You’ll also feel the effects of being at high altitude; the lift starts at 8,000 feet. The Red Pine Lodge at the bottom of the lift serves delicious gourmet food at reasonable prices. You don’t even have to take the free Cabriolet up from the main parking lot—there’s a free parking lot farther up, at the east end of the village.
If High Meadow terrain seems too easy to give you much of a workout, try descending in a run—though that puts strain on the knee ligaments while putting you at risk for a sprained ankle, and isn’t recommended for any but the most well-conditioned athletes. For a longer, but still mellow walk down the mountain, you can also try the Needles Gondola at Snowbasin in Ogden. The toughest, most painful and most pro workout is Snowbird, but that resort got so much snow this season that much of it is still there; you’ll have to wait a few weeks before you can do the walk down from the top of the tram. But, if you want to get your legs athletically conditioned in a hurry, a walk down Snowbird is the way to do it.