title: Force-velocity and power-velocity relationships during maximal short-term rowing ergometry.
abstract: BACKGROUND
  Maximal rowing power-velocity relationships that exhibit ascending and descending limbs and a local maximum have not been reported. Further, duty cycle (portion of the stroke occupied by the pull phase) is unconstrained during rowing and is known to influence average muscular power output.
  
  
  OBJECTIVE
  Our purposes for conducting this study were to fully describe maximal short-term rowing force-velocity and power-velocity relationships. Within the context of those purposes, we also aimed to determine the apex of the power-velocity relationship and the influence of freely chosen duty cycle on stroke power.
  
  
  METHODS
  Collegiate varsity male rowers (N = 11, 22.9 +/- 2.3 yr, 84.1 + 12.1 kg, 184 +/- 7 cm) performed five maximal rowing trials using an inertial load ergometer. For each stroke, we determined force and power averaged for the pull phase and the complete stroke, instantaneous peak force and power, average handle velocity for the pull phase, handle velocity at peak instantaneous force and power, pull time, recovery time, and freely chosen duty cycle. Force-velocity and power-velocity relationships were characterized using regression analyses, and optimal velocities were determined from the regression coefficients.
  
  
  RESULTS
  Pull force-velocity (r2 = 0.99) and peak instantaneous force-velocity (r2 = 0.93) relationships were linear. Stroke power (r2 = 0.98), pull power (r2 = 0.99), and instantaneous peak power (r2 = 0.99) were quadratic, with apexes at 2.04, 3.25, and 3.43 m x s(-1), respectively. Maximum power values were 812 +/- 28 W (9.8 +/- 0.4 W x kg(-1)), 1995 +/- 67 W (23.9 +/- 0.7 W x kg(-1)), and 3481 +/- 112 W (41.9 +/- 1.3 W x kg(-1)) for stroke, pull, and instantaneous power, respectively. Freely chosen duty cycle decreased from 58 +/- 1% on the first stroke to 26 +/- 1% on the fifth stroke.
  
  
  CONCLUSIONS
  These data characterized the maximal rowing force-velocity and power-velocity relationships and identified the optimal velocity for producing maximal rowing power. Differences in maximum pull and stroke power emphasized the importance of duty cycle.
authors.affiliation: Department of Kinesiology and Health Education, The University of Texas at Austin, Austin, TX, USA.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Sprague
authors.forename: James C
authors.initials: JC
authors.lastname: Martin
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Davidson
authors.forename: Roger P
authors.initials: RP
authors.lastname: Farrar
mesh_terms: D000328:Adult; D015308:Anaerobic Threshold / Q000502:physiology*; D001696:Biomechanical Phenomena; D016552:Ergometry; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018482:Muscle, Skeletal / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D011446:Prospective Studies; D013177:Sports / Q000502:physiology*; D013997:Time Factors