Sex Differences in Heart Rate, Paddle, and Portage Speed During an International Kayak Marathon Competition.

PURPOSE: Kayak marathon competitions entail several laps and frequent portages in all boat classes. Race demands related to modern elite kayak marathon competition rules have not been evaluated. This investigation characterized mean race speed, lap and portage speeds, frequency of speed changes, and heart rate (HR) responses in elite paddlers of both sexes. METHODS: During the 2022 European Marathon Championships, national team marathon paddlers in the K1 and K2 classes (N = 30, 15 women) wore a chest belt with integrated global positioning system and HR sensors. RESULTS: Elite kayak marathon paddlers maintain an exercise intensity of 85% to 91% HRmax irrespective of sex and boat type. Mean and peak paddling speeds were lower for women compared to men (P values ranging: .001-.001). In K1, men had more relative speed shifts of both 5% to 10% (35.6 [16.3] vs 25.5 [10.6]; P = .0283) and above 10% (P values ranging .0283-.0003). In K2, there were no statistical differences in speed shifts. In all boat classes, mean boat speed of the final 100 m was always significantly faster than the mean speed of the first part of the lap (P values ranging: .0105-.00000001). Portage running speed varied by 9.4% between sexes. CONCLUSIONS: During marathon races, world-class kayak paddlers sustain a mean of 85% to 91% HRmax for a prolonged period (121-129 min), with men in K1 having more speed shifts of 5% to 10% compared to women. To handle race demands, we therefore suggest that on-water training for both sexes include high-intensity steady-state exercise interspersed by frequent, more intense speed bouts.