How Does Running Power Output Compare to Cycling Power Output?

Running power is expected to be higher than bike power because metabolic efficiency is much higher for running than for cycling. This means athletes can convert the same amount of oxygen into more power when running than we can do when cycling. Or, thinking in terms of heart rate, we can produce more power for the same heart rate. This is supported by the following peer-reviewed published research:

• Metabolic efficiency of positive work for running at 2.75 m/s is 39%, and at 3.25 m/s is 41%. (Farris and Sawicki, 2011)

• In running, efficiency increases steadily with speed from ~45% at 2.77 m/s to ~60% at 5.55 m/s. (Cavagna and Kaneko, 1977)

• A review paper on cycling efficiencies indicates efficiency for cycling is between 20 to 25% for power between 200-300 W. (Joyner and Cole, 2008)

Some researchers study delta efficiency, or apparent efficiency, which is the ratio of an increment in external mechanical power output to the increase in metabolic power required to produce it.

The primary explanation given for the difference between running and cycling relates to the passive recoil of muscle elastic elements, such as tendons, during running; which is to say in running, energy stored in the negative phase (braking) is used in positive phase (propulsion). The same is not true for cycling. 

Running power is very difficult to measure. Most researchers studying running power do so using high-speed, multi-camera motion analysis systems combined with ground reaction force data from force plates embedded in running tracks or instrumented treadmills. By computing the work done at each of the lower limb joints, then divided by step time, researchers have derived estimates for the total power in running. The table below shows external power experienced at the road and does not include internal power required for repositioning the limbs.

References:

Bibliography

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• Bijker, Kirsten E., et al. “Delta efficiencies of running and cycling.” Medicine & Science in Sports & Exercise, vol. 33, no. 9, 2001, pp. 1546–1551., doi:10.1097/00005768-200109000-00019.

• Bijker, K., et al. “Differences in leg muscle activity during running and cycling in humans.” European Journal of Applied Physiology, vol. 87, no. 6, Jan. 2002, pp. 556–561., doi:10.1007/s00421-002-0663-8.

• Cavagna, G. A., and M. Kaneko. “Mechanical work and efficiency in level walking and running.” The Journal of Physiology, vol. 268, no. 2, Jan. 1977, pp. 467–481., doi:10.1113/jphysiol.1977.sp011866.

• Cavagna, G.A, et al. “Old men running: mechanical work and elastic bounce.” Proceedings of the Royal Society B: Biological Sciences, vol. 275, no. 1633, 2008, pp. 411–418., doi:10.1098/rspb.2007.1288.

• Cavagna, G. A., et al. “The resonant step frequency in human running.” Pflügers Archiv European Journal of Physiology, vol. 434, no. 6, 1997, pp. 678–684., doi:10.1007/s004240050451.

• Farris, D. J., and G. S. Sawicki. “The mechanics and energetics of human walking and running: a joint level perspective.” Journal of The Royal Society Interface, vol. 9, no. 66, 2011, pp. 110–118., doi:10.1098/rsif.2011.0182.

• Joyner, Michael J., and Edward F. Coyle. “Endurance exercise performance: the physiology of champions.” The Journal of Physiology, vol. 586, no. 1, Jan. 2008, pp. 35–44., doi:10.1113/jphysiol.2007.143834.

• Williams, Keith R., and Peter R. Cavanagh. “A model for the calculation of mechanical power during distance running.” Journal of Biomechanics, vol. 16, no. 2, 1983, pp. 115–128., doi:10.1016/0021-9290(83)90035-0.