In rowing, the athlete has to maximize power output and to minimize energy losses to processes unrelated to average shell velocity. The contribution of velocity efficiency (e velocity; the fraction of mechanical power not lost to velocity fluctuations) to rowing performance in relation to the contributions of maximum oxygen uptake (V˙O2 max) and gross efficiency (e gross) was investigated. Relationships between e velocity and movement execution were determined.
Twenty-two well-trained female rowers participated in two testing sessions. In the first session, they performed a 2000-m time trial on a modified rowing ergometer that allowed for power losses due to velocity fluctuations. The V˙O2 max, the e velocity, and the amount of rower-induced impulse fluctuations (RIIF) due to horizontal handle and foot stretcher forces were determined in a steady state part of the time trial. RIIF was used as a measure of movement execution. In the second session, e gross was determined at submaximal intensity.
As expected, V˙O2 max accounted for the major part of explained variance in the 2000-m time (53%, P < 0.001). Velocity efficiency accounted for a further 14%, e gross for 11% (P < 0.05). Negative correlations were found between e velocity and RIIF values of several discreet intervals within a stroke cycle. The results suggest that optimal timing of forces applied to the ergometer will help minimizing power loss to velocity fluctuations.
This study indicates that a relationship exists between performance and e velocity. Furthermore, e velocity appears to be related to movement execution, in particular the timing of handle and foot stretcher forces.
Faculty of Human Movement Sciences, Research Institute MOVE, Vrije Universiteit Amsterdam, THE NETHERLANDS
Address for correspondence: Mathijs J. Hofmijster, M.Sc., VU University, Amsterdam, Faculty of Human Movement Sciences, Van der Boechorststraat 9, 1081 BT Amsterdam, The Netherlands; E-mail: email@example.com.
Submitted for publication May 2007.
Accepted for publication December 2007.