title: Pedal trajectory alters maximal single-leg cycling power.
abstract: OBJECTIVE
  Muscular power produced during in vitro cyclic contraction has been reported to vary with muscle-length trajectory. The purpose of this study was to determine whether maximal human single-leg cycling power could be similarly altered by manipulating pedal trajectory.
  
  
  METHODS
  Seven trained cyclists performed maximal single-leg cycle ergometry. Pedal trajectory was manipulated by repositioning the ergometer drive sprocket off-center with respect to the crank axle, such that the leg-extension phase occupied 42, 50, or 58% of the cycle time (LEP42, LEP50, and LEP58, respectively).
  
  
  RESULTS
  Maximum instantaneous power was 12% greater for LEP58 (1984 +/- 143 W) than LEP50 (1838 +/- 126 W), which was 8% greater than that for LEP42 (1645 +/- 112 W). Maximum power, averaged over a complete revolution of the crank, was 4% greater for LEP58 (636 +/- 59 W) than for LEP50 (613 +/- 53 W), which was 18% greater than that for LEP42 (520 +/- 43 W).
  
  
  CONCLUSIONS
  These findings, paralleling those for an in vitro model, confirmed our hypothesis that maximal single-leg cycling power could be altered by manipulating pedal trajectory. Alterations in power were likely due to concomitant effects of muscle-shortening velocity, muscle excitation, and biomechanical constraints. Additional research is needed to determine whether greater leg-extension phase ratios can elicit further increases in power and whether similar results can be obtained during bilateral cycling.
authors.affiliation: Department of Exercise and Sport Science, The University of Utah, 250 South 1850, East Room 241, Salt Lake City, UT 84112-0920, USA. jim.martin@health.utah.edu
authors.forename: James C
authors.initials: JC
authors.lastname: Martin
authors.forename: Scott M
authors.initials: SM
authors.lastname: Lamb
authors.forename: Nicholas A T
authors.initials: NA
authors.lastname: Brown
mesh_terms: D000328:Adult; D001642:Bicycling / Q000502:physiology*; D001696:Biomechanical Phenomena; D005080:Exercise Test / Q000379:methods*; D005260:Female; D006801:Humans; D007866:Leg / Q000502:physiology*; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology*; D010809:Physical Fitness; D012680:Sensitivity and Specificity