Trekking poles can reduce stress on ankle and knee joints. (Brian Vander Brug, Los Angeles Times / April 25, 2005)

A long hike into the wilderness can take a serious toll on the knees. The uneven terrain, rock slabs and sharp descents can punish knee joints and produce swelling and stiffness that can linger well after the outdoor adventure ends.

Cutting down on the compressive abuse the knees endure can help alleviate post-hike pain and protect cartilage. Hikers and backpackers can spare the knees the effects of an outdoors adventure and help improve their longevity by practicing a few simple steps, provided by the Appalachian Mountain Club.

•Carry less weight. Cutting down on the weight of your backpack can reduce up to 40 pounds of downward pressure on your knees. Keeping fit and your body weight in check will also help lower the knee stress.

•Use trekking poles. This can reduce the compressive forces on the knees by as much as 25 percent. But always use two poles. Relying on one pole can increase the pressure on the unaided knee.

•Wear properly fitting shoes with quality insoles. Inserts that typically come with most footwear offer little shock absorption help when out on a nature trail. Moreover, many inserts found at both pharmacies and outdoor gear shops may not stand up to prolonged hiking. Therefore, you should consider a more rigid type of insert made of plastic and dense foam, which can carry you for hundreds of miles.

Maybe it's the shoes

We often form a tight bond with our exercise shoes. So it can be a bit difficult to let go of them when they no longer provide suitable support.

Most running and walking shoes can typically last up to 500 miles. But how, where and how much the shoes get used can shorten their useful time. Running on pavement, for instance, can lead to quicker wear and tear of shoes than running on a dirt track or hiking on trail.

How do you know when to let go of exercise shoes that have outlived their effectiveness? Here are a few indicators, from REI outfitters:

•Press test: Perform this test to determine if the midsoles still provide proper cushioning. With your thumb, push on the outsole upward into the midsole. If the midsole shows heavy compression lines with a minimal amount of compression, there is little or no cushioning left. The midsole on new shoes will compress into lines or wrinkles.

•Appearance: Don't worry about dirt and grime. They're signs of use. What you should look for are signs of wear and tear, such as heels that have stretched out and outsoles that have worn down. Also, if your shoes have seemingly molded to your feet, that's another indication of excessive wear.

•Feel: Aches and pain in your feet, knees, hip or back are a strong indication that your shoes have lost their cushioning. Additional signs include friction or blisters in unexpected places.