What's the most efficient way to climb stairs?

Ricky Nathvani put his best foot forward to answer James' question, enlisting the help from Dr Dan Gordon, a physiologist and athlete himself from Anglia Ruskin University…

Dan - If we take a standard flight of stairs, they have a typical height of about 18 cms and the depth is also about 18 cms. Additionally, we have an additional cost associated with the lengthening and the shortening of the muscle. So, if we’re going to look at this, we’re going to have to make three assumptions:

The first one is that using every step would have a quicker step rate than taking two steps at a time.

The second assumption is that taking two steps at a time would be associated with a greater height and length displacement per step than one step at a time.

The third assumption is that the stepping rate does not change over time.

Ricky - That makes sense. Two at a time is slower, but it involves greater amounts of work to get up the extra height and length. So which one is more efficient? Throw some numbers at me, Dan…

Dan - We can estimate that for a standard flight of stairs that one step at a time would be associated with an oxygen cost per step of  0.1 mls per kilogramme per minute, compared to 1.1 mls per kilogramme per minute per step when taking two at a time.

So, taking two steps at a time would cost more energy and work your heart harder despite lower muscle actions. The reason being these actions have to be more forceful to overcome the increased height.

Ricky - So, two at a time wins for the workout unless, like me, you want to be as lazy as possible, in which case stick to one by one. But which method is better for James if he wants to build either muscle strength or cardiovascular fitness?

Dan - Well, this is a bit hard to answer. We’ve previously assumed that the stepping rate is constant. However this may not be the case because, as we know, the body temperature starts to rise, energy stores will start to deplete over time. Given that there is an energy cost using two steps at a time, we can right assume that this will induce fatigue sooner compared to one step at a time.

Also, given that when taking two a time you are stepping more slowly but using a greater force, and knowing that using high force at low speed is better for building strength, we could apportion two steps at a time being more strength orientated.

To develop cardiovascular fitness, however, we need to maintain the exercise for a prolonged period of time without getting too tired, which seems to fit the one step at a time approach.

Ricky - There you go, James. One at a time is better for cardio but two by two builds strength better. Thanks Dan for your help with that one.

Next time we’ll be sounding out this question from George:

When watching a film or documentary, a falling bomb or a missile always has a descending sound or a whistle. Why is this? Does it mean that if the missile fell down a bottomless hole the sound would go subsonic?