Into extreme uphill running? A new study may help you find the best path to the top

The start of a VK Race, photo from

First of all, let's define "extreme uphill running." This is a description used to explain a "Vertical Kilometer" race, or "VK" race. It's basically like the end of the Mt. Ashland Hillclimb; athletes will climb up (running or walking) steep hillsides ranging between 10 degrees and 30 degrees to ascent 1,000 meters over a distance less than 5k. In other words, 1,000 m in altitude gain over less than 3.1 miles. Unlike most footraces, the "distance" is measured by the altitude gain, not the linear distance. There are levels of competitors in this sport, much like you have a range of finish times for a road race. The world record for a VK course (with and average slope of 31 degrees) was 29:42. There aren't a huge volume of these events in our area, but there are some nice hills. (Check out the Altra Sky Runner Series for U.S. VK races.) Whether or not you seek out a VK race, this study done by researchers at CU-Boulder may interest you and give you some food for thought about your hill training. "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,” said Rodger Kram, who is an associate professor in CU-Boulder’s Department of Integrative Physiology and senior author of the study.



What that means is that in order to ascend a slope most efficiently, you should choose trails that keep you between 20 degrees and 35 degrees. For reference, Kram notes that an average treadmill’s max incline is about 9 degrees. He explains how these finds can help you to select a route which, while longer in terms of actual distance, are actually quicker because of the difficulty in climbing the slope.

Kram summarized the findings via an analogy: “Imagine that you are standing in Colorado at a trailhead where the base elevation is 9,000 feet. Your friend challenges you to race to the summit of the mountain, which tops out at 12,280 feet, i.e. 1,000 meters of elevation gain. (Remember, one meter is about 3.28 feet.) There are several different trails that go to the summit. They are all pretty steep and some are extremely steep. One trail averages 10 degrees incline and the sign says it is 3.6 miles long. A second trail averages 30 degrees, but is only 1.25 miles long. A third trail averages 40 degrees, but only 1 mile 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.”

The study focused on a vertical rate of ascent of just over 1 foot per second, a pace that the high-level athletes could sustain aerobically 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.

The study examined 15 competitive mountain runners as they ran and walked on a custom-made treadmill, able to be set to an incline up to 45 degrees, at seven different angles ranging from 9 to 39 degrees. The treadmill speed was set so that the vertical rate of ascent was the same.  Thus, the treadmill speeds were slower on the steeper angles. The athletes were unable to balance at angles above 40 degrees, suggesting a natural limit on the feasible slope for a VK competition.

“Very few people walk or run up such steep slopes, but by going to extremes, we broaden our horizons and investigate the limits to human performance,” said Kram.

As for amateur runners who aren’t planning to try a VK race anytime soon?  “These findings indicate that you can still get a good aerobic workout simply by walking up very steep inclines,” Kram said.

So the next time you are out on a run, turn a corner on the trail or round a building to find a giant climb in front of you, remember that there are “hills” and there are “walking hills.” I’m a big fan of walking hills, because I frequently can still feel my heart pounding and my muscles working even though my breathing gets a bit of a break. It’s definitely still a challenge, but I’m ready to pick up the pace again at the summit.

Nicola Giovanelli, a visiting scholar from the University of Udine, Italy; Amanda Ortiz, a CU-Boulder cross-country runner and undergraduate student in the Department of Integrative Physiology; and Keely Henninger, who now works for Nike, co-authored the study. All three are competitive mountain runners and Ortiz was the 2013 Junior World Mountain Running champion.

The University of Colorado Boulder Undergraduate Research Science Training (BURST) and Undergraduate Research Opportunity Program (UROP) supported the research.

If you happen to live in the Boulder/Denver area and are interested in being a participant in future uphill running experiment, contact

About Kelly Barten (1152 Articles)
I started the Run Oregon blog in February 2007, because I felt like running in Oregon and SW Washington deserved more positive coverage. I also wanted to level the playing field so that small, non-profit races could compete with big events; and to support LOCAL race organizers. I'm a Creighton Bluejay (undergrad) and an Oregon Duck (Sports Marketing MBA), and I live in Tigard with my husband and two kids. My "real job" is working for an incredibly awesome math textbook company doing marketing and production.
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