Effect of Crank Length on Joint-Specific Power during Maximal Cycling


Medicine & Science in Sports & Exercise:
doi: 10.1249/MSS.0b013e3182125e96
Applied Sciences

Previous investigators have suggested that crank length has little effect on overall short-term maximal cycling power once the effects of pedal speed and pedaling rate are accounted for. Although overall maximal power may be unaffected by crank length, it is possible that similar overall power might be produced with different combinations of joint-specific powers. Knowing the effects of crank length on joint-specific power production during maximal cycling may have practical implications with respect to avoiding or delaying fatigue during high-intensity exercise.

Purpose: The purpose of this study was to determine the effect of changes in crank length on joint-specific powers during short-term maximal cycling.

Methods: Fifteen trained cyclists performed maximal isokinetic cycling trials using crank lengths of 150, 165, 170, 175, and 190 mm. At each crank length, participants performed maximal trials at pedaling rates optimized for maximum power and at a constant pedaling rate of 120 rpm. Using pedal forces and limb kinematics, joint-specific powers were calculated via inverse dynamics and normalized to overall pedal power.

Results: ANOVAs revealed that crank length had no significant effect on relative joint-specific powers at the hip, knee, or ankle joints (P > 0.05) when pedaling rate was optimized. When pedaling rate was constant, crank length had a small but significant effect on hip and knee joint power (150 vs 190 mm only) (P < 0.05).

Conclusions: These data demonstrate that crank length does not affect relative joint-specific power once the effects of pedaling rate and pedal speed are accounted for. Our results thereby substantiate previous findings that crank length per se is not an important determinant of maximum cycling power production.

Author Information

1Centre for Sports Medicine and Human Performance, Brunel University, Uxbridge, UNITED KINGDOM; 2Department of Performance Analysis and Biomechanics, English Institute of Sport, Manchester, UNITED KINGDOM; and 3Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT

Address for correspondence: Thomas Korff, Ph.D., Centre for Sports Medicine and Human Performance, Brunel University, Uxbridge UB8 3PH, United Kingdom; E-mail: thomas.korff@brunel.ac.uk.

Submitted for publication June 2010.

Accepted for publication January 2011.

©2011The American College of Sports Medicine