Sit or Stand: Tradeoffs in Efficiency?


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

  1. on a stationary indoor bike (Wingate test, a standard anaerobic power test).
  2. seated on a slightly ascending road.
  3. 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 percent 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 to 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 four to five 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 20,000 to 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 percent) 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 favor 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!

References

    1. Millet, G. P., C. Tronche, N. Fuster, and R. Candau. Level ground and uphill cycling efficiency in seated and standing positions. Med Sci Sports Exerc. 34:1645-1652, 2002.


Stephen Cheung is a Canada Research Chair at Brock University, with a research specialization in the effects of thermal stress on human physiology and performance. He can be reached for comments at stephen@pezcyclingnews.com.

PezCycling News: We tap into what's cool in elite level pro cycling and make the news fun again—every day. Check out our off-beat rider interviews, top level tech reviews, weekly training & fitness articles, cool stories on top rides, race news and reports the way we like 'em, the lovely Daily Distractions and cool stories you can't find anywhere else. Get Pez'd today.

Related Links:

Sitting Vs. Standing When Cycling Uphill

Should You Sit or Stand When Riding Uphill?

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