Many a trail runner - beginner or pro - has posed the question - when is it more efficient to run when tackling steep climbs? The following is a excert on this topic from an article composed by Ian Corless (http://iancorless.org/2015/12/22/running-or-walking-efficiency-when-climbing/):
On December 15th, the University of Colorado Boulder released a document called, CU-Boulder researchers discover optimal range of slopes for extreme uphill running. They posed the following question:
“Imagine that you are standing in Colorado at a trailhead where the base elevation is 9,000 ft/2743 m). Your friend challenges you to race to the summit of the mountain, which tops out at 12,280 ft/3743 m, roughly 1,000 meters of elevation gain. There are several different trails that go to the summit. They are all steep and some are extremely steep. One trail averages a 10 degree incline and the sign says it is 3.6 miles/5.8km long. A second trail averages 30 degrees, but is only 1.25 miles/2km long. A third trail averages 40 degrees, but only 1 mile/1.6km long. To get to the summit the fastest, which trail should you choose and should you walk or run?”
“Based on our research, we now know that choosing the second trail (30 degrees) and walking as fast as you can within your aerobic capacity is the fastest way to go,” Kram said. “For either running or walking, slopes between 20 and 35 degrees require nearly the same amount of energy to climb the hill at the same vertical velocity.”
“A vertical rate of ascent of just over 1 foot per second, is a pace that high-level athletes could sustain during the testing. At that speed, walking used about nine percent less energy than running. So, sub-elite athletes can ascend on very steep uphills faster by walking rather than running.”
Ian closes with the following summation: When participating in ultra events, reverting to periods of walking may well produce greater results and faster times. This is very evident when the terrain steepens; running will only expend more energy and produce slower times. The use of poles appears to benefit performance when gradients steepen, this is not scientifically confirmed.
Credit: Summized here with permission from the author, Ian Corless To read the full article please click here