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Research Christmas 2010: The Lives of Doctors

Bicycle weight and commuting time: randomised trial

BMJ 2010; 341 doi: (Published 09 December 2010) Cite this as: BMJ 2010;341:c6801
  1. J Groves, consultant in anaesthesia and intensive care
  1. 1Department of Anaesthetics, Chesterfield Royal Hospital, Calow, Chesterfield, UK
  1. Correspondence to: J Groves jeremy.groves{at}


Objective To determine whether the author’s 20.9 lb (9.5 kg) carbon frame bicycle reduced commuting time compared with his 29.75 lb (13.5 kg) steel frame bicycle.

Design Randomised trial.

Setting Sheffield and Chesterfield, United Kingdom, between mid-January 2010 and mid-July 2010.

Participants One consultant in anaesthesia and intensive care.

Main outcome measure Total time to complete the 27 mile (43.5 kilometre) journey from Sheffield to Chesterfield Royal Hospital and back.

Results The total distance travelled on the steel frame bicycle during the study period was 809 miles (1302 km) and on the carbon frame bicycle was 711 miles (1144 km). The difference in the mean journey time between the steel and carbon bicycles was 00:00:32 (hr:min:sec; 95% CI –00:03:34 to 00:02:30; P=0.72).

Conclusions A lighter bicycle did not lead to a detectable difference in commuting time. Cyclists may find it more cost effective to reduce their own weight rather than to purchase a lighter bicycle.


  • I thank C Cooper and H Spencer for their helpful comments and R Groves for proofreading the manuscript and checking the maths.

  • Funding: The study was entirely funded by the author and the author has no commercial relationship with any bicycle manufacturer or commercial cycling enterprise.

  • Competing interests: The author has completed the Unified Competing Interest form at (available on request from the corresponding author) and declares: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; and no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: Ethical approval was not obtained as the sole investigator and subject was the author. The research was conducted on his regular journey to and from work using his normal mode of transport.

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