The Rest Step:
The rest step is a technique where you lock you knee momentarily at the apex of your step, so your body weight is borne by the skeletal structure of the leg giving the big muscles, quadriceps and gluteus a rest. Saving you nearly a second of exertion each step, which adds up.
Exhale as you relax then inhale and take the next step.

For extreme mountaineering you can actually pause with your weight on the back leg. This will result in several breaths per step.

In addition, you slow your rate of walking and take smaller steps. Slowing your cadence goes hand in hand with the rest step. By walking more slowly, you can walk continuously without taking breaks. This is very useful on winter hikes where you want to keep your temperature steady and remain as dry as possible. food.

See:
The Rest Step - Winter Hiking Footwork | Section Hiker Video
Video: Tips for Uphill Hiking | eHow.co.uk
Video The Rest Step | New York-New Jersey Trail Conference
The Rest Step | Backpacker Magazine
Mountaineering: The Freedom of the Hills - Wikipedia, the free encyclopedia

Other Techniques:
How to Walk - Backpacker Magazine 2011
Additional Uphill Hiking Techniques
How to Improve Your Hiking Technique: WikiHow.com Links: