found this sports science article and the use of trekking poles. Everyone who says they don't need or want to use trekking poles might want to reconsider how much they benefit your body especially when carrying a heavy pack.
a lot of other interesting facts and articles out there on the web, go check it out.
- Fewer injuries. Poles reduce the risk of injury and tendonitis in knees, calves, thighs, and even hips, according to Michael Torry, Ph.D., director of biomechanics research at Steadman-Hawkins. Trekking poles also allow hikers to keep a more normal stride and a faster pace with less effort.
- Less pounding. Up to 4.4 percent of the force that reverberates through your body with each step is absorbed by the poles. After a long day and thousands of steps, that support adds up.
- Relief for ailing knees and joints. Dr. Torry says that angling the tips of your poles forward slightly can reduce the compression in your joints as you hike downhill. When hiking uphill, angle the poles backward for an extra boost and reduced ankle stress.
- Fewer face plants. While researchers didn't test stability, they agree with what many backpackers already know: Four legs are better than two on uneven terrain.
- Less fatigue. According to Christopher Knight, Ph.D., who led the study at the University of Massachusetts, properly used poles (see "Proper Pole Use" below) reduce the workload for lower-body muscles and joints by transferring some of the load from your legs to your arms. Subjects in Dr. Knight's study (who hiked with loaded packs for an hour on a treadmill) said the trek felt easier with poles.