The effect of stroke rate on performance in flat-water sprint kayaking
McDonnell, Lisa Kelly
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Stroke rate has been implicated as an important determinant of sprint kayaking performance via correlation analysis. This thesis determined the effect of stroke rate on sprint kayaking performance including: (1) What stroke rates are required to achieve medal winning times?; (2) What are typical self-selected stroke rates of New Zealand paddlers?; (3) Do paddlers respond well to stroke rate feedback?; and (4) What is the effect of increasing stroke rate on performance and technique? Two literature reviews, one quantitative descriptive performance analysis, two quantitative experimental reliability studies, two quantitative experimental biomechanical studies, and one quantitative experimental intervention study were completed. Elite K1 200-m world championship medallists’ average stroke rates ranged 144-168 spm for men and 131-147 spm for women in competition. New Zealand elite paddlers (males and females) typically rated 98-101 spm, but tests were limited to 300-m sprint training at “race pace” and during the last stage of an incremental ergometer test. It was best to assess stroke rates using time-trials. The typical self-selected stroke rates of New Zealand male sub-elite paddlers were 122 ±11 spm during K1 200-m time-trials. While metronome feedback targets were not fully achieved when increasing stroke rate by 5-10 spm, the metronome was effective for increasing stroke rate by 4-5 spm (2.9-4.2%). The stroke rate increase led to a 200-m performance time enhancement of 0.9-1.0% for sub-elite paddlers, where a general trend existed that faster paddlers responded better to the stroke rate increase. Other key variables that indicated better performances were shorter water phase times, aerial phase times, entry sub-phase times and exit sub-phase times. Overall, absolute phase and sub-phase times reported in seconds were more associated with performance than relative phase and sub-phase times. Increasing stroke rate using metronome feedback also caused reductions in water and aerial phase times. Water phase times were reduced primarily by reductions in pull sub-phase times. Pull sub-phase times were not significantly associated with performance, possibly indicating variability in the efficiency of the pull phase between skill levels on-water. Key segmental sequencing variables important for inducing a stroke rate increase between intensities were shorter durations of the pull arm, trunk, and leg actions. Decreasing forward reach was inevitable and decreasing pull arm time was the most important variable for increasing stroke rate, so paddlers should focus on reaching as far forward as possible without hindering their ability to quickly direct the paddle backward. Trunk rotation and leg extension movements increased with intensity and are considered important for performance theoretically for achieving greater paddle tip velocity when the blade enters the water by utilising a greater leg pedalling motion. In conclusion, New Zealand paddlers typically rated well below the recommended stroke rates required to achieve medal winning times in the K1 200-m event. Metronome feedback was effective for eliciting an acute stroke rate increase of 4-5 spm (2.9-4.2%), which led to performance enhancements of 0.9-1.0% in K1 200-m time-trials. Further research is needed to determine the ideal training strategies for making larger increases in stroke rate without losing efficiency in the pull sub-phase.