Sit or stand: Tradeoffs in efficiency?

Dr. Stephen Cheung, Ph.D.
PezCycling News

Varying our positions on the bike is required in order to adapt to different terrain or riding situations, or simply to give our body a break from being stuck in the same position and stressing the same muscles. While we know that standing is great for giving us more power, what are the effects on metabolic demand and efficiency?


Boy you've got to carry that weight...
When we think of weight-bearing exercises, the first and most obvious one is running. That's because, in addition to propelling yourself forward, a lot of energy is required simply to keep yourself upright and stabilize yourself.

Added to that is the impact force from landing on your feet each stride. It's the combination of the two that makes for a much higher heart rate, metabolic rate and overall stress when running compared to cycling. It also helps to explain why Lance felt the NY Marathon was tougher than any ride he did during his cycling career.

Cycling is mostly a non-weight bearing activity, and the bicycle is a highly efficient machine especially because it removes the impact forces and also because the cycling position cradles our body and minimizes the need to support our own weight for the large part.

However, there are times where we have to support a good deal of our body weight, and that's when we're standing. Whether it's on the flats, the hills or in a sprint, we are no longer supporting weight on the saddle, and have to rely on our muscles more to keep ourselves upright.


Tradeoffs in efficiency?
Of course, this is why standing typically costs more energy, but it's also the leveraging of more of your body weight over the pedals, along with the recruitment of additional muscles, that produces the higher power outputs possible when standing as opposed to sitting.

This is one of the main reasons why we're generally taught to keep the standing to a minimum and when you need extra power, such as initiating an acceleration (e.g., sprint, breakaway) or when you need the extra power while climbing. Wind resistance is also higher while standing due to the larger surface area you're exposing.

I have written extensively on efficiency in various forms over the past couple of years, and that's because it is the single biggest pathway to increasing the power output you can lay out on the road. To refresh your memory, check out the article on Lance's improvements in pedaling efficiency from 1993 through his first Tour victory. So this begs the question: while standing may provide more power and also cost more energy, is there a difference in the efficiency (gross efficiency defined as power output: energy consumption) between standing and sitting?


To the books
You know where I'm heading with this -- straight to the library. Doing so is always such a humbling experience, because I almost always come across one of those "why the heck didn't I think of doing this?" experiments that have me kicking myself.

This time around, it's a French research group from Montpellier that's making me black and blue from the kicking (1). The experiment itself is ridiculously simple: have fit cyclists ride for 6 min at 75 precent VO2max in the following conditions:

flat (velodrome) in a seated position (done twice).
5.3 percent gradient hill in a seated position (done twice).
5.3 percent gradient hill in a standing position.

Seated position consisted of riding in the drops. Standing position was done with the hands on the hoods.

Subjects also did a 30s all out sprint in three conditions over the same day:

on a stationary indoor bike (Wingate test, a standard anaerobic power test).
seated on a slightly ascending road.
standing on a slightly ascending road.

Thanks to the improvements in technology, the researchers were no longer constrained to the lab and could take this study out onto "real" terrain and on the subjects' own bikes, increasing the applicability of the study. Namely, each subject's bike was equipped with a SRM "Pro" crankset to determine power output. To measure energy consumption, subjects carried a small and highly portable Cosmed metabolic cart, weighing about one kg or less.

Data analysis consisted of calculating "gross efficiency" (power compared to energy consumption). 100% would mean that every bit of energy was converted from chemical to mechanical energy and producing forward motion.

This is pretty much an impossibility, and humans are typically 20-25 percent efficient, with the remainder of the energy converted to heat energy. Also calculated was "economy," or the amount of power produced per each liter of oxygen you breathed in. Typical values are about 4-5 kJ of mechanical energy per liter of oxygen.

Just the facts
Very simple and nicely designed study. What were the results?

Subjects were eight highly-trained cyclists, including two professionals riding 20-30,000 km/y. the others were elite junior or national-level cyclists.
As expected, power was not different across the different positions, because subjects were required to keep a similar 75 percent VO2max workload. Wattage was about 290 W for the six min, not easy!
Also as expected, heart rate was about eight bpm higher when standing compared to seated uphill. Ventilation was also higher, though no differences were seen in oxygen consumption. Cadence was similar at just under 60 rpm in both conditions.
Most importantly to answering our question, no differences were found in either gross efficiency (~22.5%) or economy (4.7 kJ of power per L of oxygen).
In the 30s tests, maximum and mean power were much higher in the standing than seated positions (mean power of ~820 and 650 W, respectively), despite similar cadences and blood lactate values.

Summary
For the large part, the findings of this study are not major surprises, nor were there any surprises intended to begin with. The ability to produce higher power when sprinting and standing is fairly evident, as are the higher heart rates when climbing and standing. The main novelty of the study comes in the analysis of efficiency, and the interesting nugget of information is that there were no differences in efficiency or economy while standing or seated.

This means that, while standing is a bigger stress on our aerobic and cardiovascular system, it does not necessarily mean a decrease in efficiency itself. So standing is not going to disproportionately cost more energy to perform, when you factor in the greater power you are generating. Applying this information to the road, you are NOT "wasting" energy by standing.

The caveat, however, is that practice is required to build good form and technique while standing, and likely especially so when you start becoming tired and fatigued. I remember during my graduate days at Simon Fraser University, I would often practice my technique by standing up the entire five km of the eight percent hill up to campus.

Another caveat is that all of the subjects in the study were young, lean, and light, averaging 67 kg. If you're a bigger rider, the efficiency equation might remain tilted in favour of sitting. Regardless, practice remains a vital component of good technique, so keep mixing up your workouts and remember that technique and efficiency remains the key to maximizing cycling performance!

How do those experience rider sprint with moving the bike left and right while standing and mashing the pedal? I can mash the pedal while standing but can't do the bike left and right. hahaha

Welcome to Fil-Chi Cycling K2!

I ride an MTB myself, we'll have to wait for Cbike and others to acknowledge this thread and explain on how to stand and pedal. hehehe

K2 wrote:How do those experience rider sprint with moving the bike left and right while standing and mashing the pedal? I can mash the pedal while standing but can't do the bike left and right. hahaha

I've read some literature on mashing...
I'm not sure about your question but here goes.


When standing up to mash the pedal, there is a weight transfer and tilting of the bike involved
which allows maximum power.
This is done by tilting the bike in such a way that your mashing leg (the one pushing down) is always upright (90 DEGREE to the ground).



Try to do it real slow, tilt or lean the bike to the left while your right leg is mashing down.
Swing the bike to lean to the right when it is your left leg's turn to mash down.


This allows maximum power.
Do it very fast and you see the bike being tilted left and right,
people starts to say you're crazy because the bike is shaking too much,
but in reality, it's the fastest way to go!


I do this when I'm climbing our parking ramp, which is more than 30 degree slant.
I can't go fast because the tires will skid.
I can't pedal seated because it will strain my knees too much.
I stand mashing the pedal, even though slowly, the power is there because I'm tilting the bike left and right.


Did I confuse everybody already?



My 2 cents worth