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David A. Aitken and Robert J. Neal

A system was developed to quantify the on-water forces, impulse, and power generated by a kayak paddlet. The system is lightweight (<1 kg), portable (i.e., it can be used in single [Kl], double [K2], and fours [K4] boats), and does not affect the integrity of either the kayak paddle or the boat. Changes in the strain on the kayak paddle were measured by force transducers attached to the shaft of the paddle, and these signals were then recorded on an FM tape recorder located in the boat. The data were then analyzed by the Kayak Data Acquisition and Analysis System software which graphically presented the paddlers' force time curve as well as a printed tabular report on the paddlers' average force, impulse, work, power, and the instantaneous boat velocity.

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Robert L. Woolfolk, Shane M. Murphy, David Gottesfeld and David Aitken

An investigation was carried out concerning the effect of imagery instructions on a simple motor skill accuracy task (putting a golf ball). Male college students (N = 50) were randomly assigned to one of six experimental conditions in a design that allowed the presence or absence of mental rehearsal of the physical movements involved in the task to be completely crossed with the imaginal depiction of task outcome (successful, unsuccessful, or no outcome component). A significant outcome by trials interaction was found on task performance. This finding reflected the degradation of performance in the conditions employing negative outcome imagery rather than any enhancement of performance by positive outcome imagery. Self-efficacy was found to be correlated with performance, but this association seemed to be a by-product of the strong relationships between these variables and performance on the previous trial. Results are discussed in relation to the existing literature, and future research directions are delineated.

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Thiago Oliveira Borges, Nicola Bullock, David Aitken and Aaron J. Coutts

Methods:

This study compared 3 commercially available ergometers for within- and between-brands difference to a first-principle calibration rig.

Results:

All ergometers underestimated true mean power, with errors of 27.6% ± 3.7%, 4.5% ± 3.5%, and 22.5% ± 1.9% for the KayakPro, WEBA, and Dansprint, respectively. Within-brand ergometer power differences ranged from 17 ± 9 to 22 ± 11 W for the KayakPro, 3 ± 4 to 4 ± 4 W for the WEBA, and 5 ± 3 to 5 ± 4 W for the Dansprint. The linear-regression analysis showed that most kayak ergometers have a stable coefficient of variation (0.9–1.7%) with a moderate effect size.

Conclusion:

Taken collectively, these findings show that different ergometers present inconsistent outcomes. Therefore, we suggest that athlete testing be conducted on the same ergometer brand, preferably the same ergometer. Optimally, that ergometer should be calibrated using a first-principle device before any athlete testing block.