What's the most efficient way of running up stairs?

James, you asked which is more efficient when climbing stairs, one or two steps at a time.

The best answer is that there is very little difference. I was interested in the same question about 4 years ago.

Halsey (2012) investigated the energetic costs and found that when climbing stairs, taking two steps at a time was roughly 12% more efficient than one step at a time (http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0051213). To quote from their discussion; "For example, climbing just a 15 m high stairway five times a day represents an energy expenditure of on average 302 kcal per week using the one step strategy and 266 kcal using the two step strategy."

Listening to this podcast, I am concerned that the listener will be misled. Dan states (2:05 into the podcast) that the cost per 'step' for one step at a time is 0.6 ml O2 kg-1 min-1 compared to 1.1 ml O2 kg-1 min-1 per step when taking them two at a time. This would make two steps at a time almost twice as energetically expensive as one at a time. I cannot find any evidence to support this.

I think there is some confusion here as to what a 'step' is - is it the physical thing you are climbing or the action of moving the leg from one position to another? And, the use of mls O2 kg-1 min-1 is not helping since when climbing two steps at a time the ascent rate is faster.

Aziz & Teh (2005) (https://www.jstage.jst.go.jp/article/jpa/24/4/24_4_253/_pdf) found, like Halsey (2012), that double-steps were more efficient than single stepping - but the effect was marginal. To quote, "The higher calorie expended with the SS compared to the DS pattern was deemed to be of little practical significance."

My own view - having had students conduct similar experiments - is that Aziz & Teh were right. There is very little difference in energy terms between the two approaches. It is simple physics - the higher you go the more energy you use no matter what the strategy. If you are using stairs to get fit, do more of them. I have found that about 25 ascents of 15.9m which takes me around 40 mins is a pretty good workout especially since I have an empty staircase just the other side of my lab door! https://www.strava.com/activities/87503442