Towards an understanding of crew boat sprint kayaking : on-water investigations of stroke synchronisation, seat order, and performance

Abstract

Crew boat racing is widely practiced around the world in many forms. In the Olympic sport of sprint kayaking, athletes compete in the one-seater (K1) kayak, and the twoseater (K2) and four-seater (K4) crew boats. While performance factors have been studied extensively in K1, the literature on crew boats is limited despite its inherent differences to K1. The aim of this thesis was to improve the current understanding of the unique elements associated with crew boat racing. A series of four studies and two case studies investigated stroke synchronisation, seat order, and performance in crew boat sprint kayaking from kinematic and kinetic approaches.<br><br>First, a video-based method was developed in Study 1 to profile stroke characteristics of sprint kayak crews. Intra- and inter-rater reliabilities of this method were assessed to be almost perfect for raters with sprint kayaking experience. Timing differences were generally small (< 21 milliseconds) within each national team K2 crew, but there were different stroke synchronisation patterns across crews. Case Study 1 of a national team K4 crew revealed that the 2nd seat paddler was most out-of-sync from the 1st seat paddler. In Case Study 2, stroke synchronisation patterns of an experienced K2 crew were similar over four weeks.<br><br>Next, the video-based method was used in two investigations on national team K2 crews. In Study 2, the importance of vision on 200-m performance time and stroke synchronisation was explored through a technique drill which required the back paddler to close his/her eyes midway. From magnitude- based inferences, the ‘eyes closed’ condition had a 59% chance of worsening 200-m performance time by a trivial amount. The effects on stroke synchronisation were unclear. In Study 3, there were no clear differences between the preferred versus reversed seat orders for 200-m performance time and stroke synchronisation, mainly because the preferred seat order was slower for four out of eight crews.<br><br>Finally, Study 4 examined if K2 performance could be explained by crewspecific factors of a large sample of 72 crews comprising national team, recreation club, and school athletes. Using instrumented paddles, each crew performed a step protocol in their preferred followed by reversed seat order. Almost half of the crews (44%) chose the wrong seat order, i.e., their preferred seat order was slower. Most stroke force and power parameters could differentiate the national team crews from the rest. Among the crew-specific factors, the combined stroke parameters of stroke rate and peak power could best explain K2 performance (up to 91.3%).<br><br>There were three key findings from this thesis. First, stroke synchronisation was not critical for successful K2 performance. Second, seat order matters for K2 performance, however, the reversed seat order may be faster than the preferred seat order. Third, K2 performance was best explained by the combined stroke parameters of stroke rate and peak power. Based on the findings in this thesis, it is recommended that to improve crew boat sprint kayaking performance, practitioners should direct their efforts towards increasing stroke rate and peak power instead of emphasising precise stroke synchronisation.