To cite this Article Hofmijster, Mathijs J. , Landman, Erik H. J. , Smith, Richard M. and Van Soest, A. J. Knoek(2007) 'Effect of stroke rate on the distribution of net mechanical power in rowing', Journal of Sports Sciences, 25: 4,[403][404][405][406][407][408][409][410][411] To link to this Article: DOI: 10.1080/02640410600718046 URL: http://dx.doi.org/10.1080/02640410600718046Full terms and conditions of use: http://www.informaworld.com/terms-and-conditions-of-access.pdf This article may be used for research, teaching and private study purposes. Any substantial or systematic reproduction, re-distribution, re-selling, loan or sub-licensing, systematic supply or distribution in any form to anyone is expressly forbidden.The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.Effect of stroke rate on the distribution of net mechanical power in rowing Abstract The aim of this study was to assess the effect of manipulating stroke rate on the distribution of mechanical power in rowing. Two causes of inefficient mechanical energy expenditure were identified in rowing. The ratio between power not lost at the blades and generated mechanical power ( P rower ) and the ratio between power not lost to velocity fluctuations and P rower were used to quantify efficiency (e propelling and e velocity respectively). Subsequently, the fraction of P rower that contributes to the average velocity ( _ x boat ) was calculated (e net ). For nine participants, stroke rate was manipulated between 20 and 36 strokes per minute to examine the effect on the power flow. The data were analysed using a repeated-measures analysis of variance. Results indicated that at higher stroke rates, P rower , _ x boat , e propelling , and e net increase, whereas e velocity decreases (P 5 0.0001). The decrease in e velocity can be explained by a larger impulse exchange between rower and boat. The increase in e propelling can be explained because the work at the blades decreases, which in turn can be explained by a change in blade kinematics. The increase in e net results because the increase in e propelling is higher than the decrease in e velocity . Our results show that the power equation is an adequate conceptual model with which to analyse rowing performance.