Long-distance hiking, particularly when done with a heavy backpack, can generate a significant amount of physical stress. Use trekking poles to decrease the strain placed upon your body and to add stability while hiking, particularly down sharp grades or over rough terrain. While some hikers choose to use only one pole or walking stick---often to support a weaker leg or to increase stability---you should use two poles to maximize your stability and to protect yourself from accidental falls, ankle rolls and general joint wear and tear.
Swing the poles naturally with the movement of your arms---as one leg swings forward, so too does the opposite arm. Plant the poles when they are positioned ahead of you as you walk, and place a comfortable amount of pressure on them as you proceed forward. When descending, plant trekking poles farther out in front of you than you would on level terrain; let them support your weight as you move downhill. When ascending, plant the poles closer to you and push yourself through each stride by placing your weight on the pole and pushing down as you pass it.
When using trekking poles, consider the various features offered and use them properly to maximize their utility. For trekking poles that telescope, increase the length when traversing downhill, and decrease the length when traversing uphill. This will allow you to maintain an ideal walking position at all grades. If you choose not to change your poles' length during very short ascents and descents, adjust your hand positions by sliding them up or down the poles as needed. Use the handle straps correctly to avoid placing undue strain on your wrists and hands---thread your hands up through the straps, allowing the portion of the strap closest to the pole to fit snugly between your palm (preferably in the crease between your index finger and thumb) and the pole. Fit the strap snugly (but not tightly) around the back of your wrist.
The most notable benefit trekking poles provide for the long-distance hiker is to reduce the load placed on your legs, feet and back by dispersing your weight over both your arms and legs. Another benefit trekking poles provide is the maximization of your time during extended trips; use trekking poles properly to increase your hiking speed, allowing you to cover more terrain in less time.
Trekking poles can damage vegetation along the trail and degrade the soil. Use trekking poles that have rubber tips, if possible. Such tips do not puncture and damage soft soils as much as composite and carbide tips. Additionally, unless you are hiking over snow-covered trails, remove the baskets---the circular rings which purportedly prevent poles from penetrating the ground. These rings often snag and damage trail-side vegetation, thus increasing trail erosion.