1. EFFECT OF BODY POSTURE ON DRAG FORCE WHILE CYCLING
C. L. Johnston – ceejohnston7@gmail.com – California State University, Chico
ISSUE
Drag resistive force accounts for up to 90% of all resistive forces during cycling (Garcia-Lopez
et al., 2008; Oggiano, Leirdal, Saetran, & Ettema, 2008). Anecdotally, by putting the body into
the optimal riding position, cyclists are able to reduce drag forces and increase power output.
Studies have examined the effect of shoulder and torso angles including factors such as handle
bar and seat height on the change of drag force and power output (Oggiano et al., 2008;
Underwood, & Jermy, 2013; Underwood, Schumacher, Butette-Pommay, & Jermy, 2011).
OVERVIEW
Due to its ability to reduce trunk angle, a low handle bar height significantly reduced drag force
while a smaller effect was observed with adjusting seat height (Garcia-Lopez et al., 2008;
Oggiano et al., 2008). When comparing handle bar height and pad separation in relationship to
resistive forces, handle bar height has been shown to significantly lower drag force area while
pad separation had minimal effects (Underwood, & Jermy, 2013). If a cyclist is striving for
maximum power output, they should be in a low shoulder angle and medium torso angle position
(Underwood et al., 2011).
CONSIDERATIONS
The best aerodynamic position did not always produce the greatest power output (Underwood et
al., 2011). Due to varying body size and shape, the present studies agree the most aerodynamic
position is not the same for all cyclist (Underwood, & Jermy, 2013; Underwood et al., 2011).
Although the importance of adjusting body posture to reduce drag was noted, there was no
standardized suggestion for optimal body posture during cycling. The best body posture to
reduce drag force while maintaining optimal power output should be carefully measured due to
individual differences. The limitations of these studies are noted in Table 1.
REFERENCES
Garcia-Lopez, J., Rodriguez-Marroyo, J. A., Juneau, C. E., Peleteiro, J., Martinez, A. C., & Villa, J. G. (2008).
Reference values and improvement of aerodynamic drag in professional cyclists. Journal of Sports
Sciences, 26(3), 277-286.
Oggiano, L., Leirdal, S., Saetran, L., & Ettema, G. (2008). Aerodynamic optimization and energy saving of cycling
postures for international elite level cyclists. The Engineering of Sport, 7, 597-604.
Underwood, L., & Jermy, M. (2013). Optimal handlebar position for track cyclists. Sports Engineering, 16, 81-90.
Underwood, L., Schumacher, J., Burette-Pommay, J., & Jermy, M. (2011). Aerodynamic drag and biomechanical
power of a track cyclist as a function of shoulder and torso angles. Sports Engineering, 14, 147-154.
Limitations noted in the referenced studies
● Differences in athletes’ shoulder width/trunk height (projected area) not taken into account
● Effect of head position on drag resistance was not measured
● Drag resistive forces not tested at adequate varying speeds
● Front wheel was not rotating during testing which may influence the power output due to friction
● High variability of the results between athletes was found when adjusting body postures
Table 1. By taking these limitation into account, future studies may be able to provide more conclusive results