Competition and training demands of junior Sprint Kayak athletes

Introduction: Sprint Kayak is an Olympic sport where women race over 200-m and 500-m and men compete over 200 and 1000-m. In 2009 the 200-m event was included into the Olympic Games’ program replacing the men’s 500-m events and providing the women with an additional event. Currently, little research is available on the demands of the 200-m event. With the inclusion of this short distance event, the training practices require review, especially in the case of young developing athletes, as this group may begin to specialise their training toward this new format. Therefore, the overall goals of this thesis were to: 1) gain a better understanding of the racing and physiological demands in Sprint Kayak, 2) develop specific methods for monitoring training and performance and 3) compare methods for training well-trained junior Sprint Kayak athletes. The results of four separate studies were reported in six manuscripts. Study 1: The split –time results from six Sprint Kayak world championships (ntotal = 486) were pooled and the pacing strategies and performance analysed according to race level (Finals A and B) and boat (K1, K2 and K4). Collectively, the world-class Sprint Kayak athletes present different pacing strategy according to final A and B), boat class (K1, K2 and K4) and from year to year. Study 2: Examined the relationships between physiological variables, including ? ̇? O2max, maximal aerobic power (MAP), lactate threshold (LT2), whole body (? ̇? O2kinetics) and muscle oxygen kinetics (MO2kinetics), muscle oxygenation parameters and on-water time-trial performances. The results showed physiological variables correlated with performance in both 200-m and 1000-m events. Furthermore, the muscle oxygenation parameters increased the predictive power of these physiological variables highlighting the importance of muscle oxygen extraction for the 200-m time-trial. Study 3: Tested a specific performance test (SKtest) in the laboratory and in the field for validity (as a performance and fitness measure) and reliability (part A). In addition, the test sensitivity was assessed during a normal training period (part B) in a separate group of well-trained junior Sprint Kayak athletes. Part A Participants (n = 11) completed a standard incremental kayak step test in the laboratory, a SKtest consisting of two sets of ten 100-m efforts with 20 s rest between efforts and 1000-m between sets in both laboratory and on-water and on-water time trials over 200 and 1000-m. Part B – Another group of athletes (n = 8) performed weekly trials of the short version of the SKtest for four weeks, in their usual training environment. The results showed the SKtest to be valid, reliable and sensitive for monitoring fitness and performance changes. Study 4: Tested the validity of methods for quantifying training load and established the relationships between training loads, physiological variables and onwater performance in well-trained junior Sprint Kayak athletes. The results demonstrated the validity of the session-RPE method for quantifying training loads in Sprint Kayak. Moreover, the inverse relationships between physiological variables, performance and training loads showed that aerobically fitter and faster athletes have lower perceived training loads when external loads are controlled. Study 5: Compared the power outputs and acute physiological responses (i.e. heart rate [HR], blood lactate [BLa], ? ̇? O2, and tissue saturation index [TSI])) of common repeated sprint (RS) and high-intensity aerobic (HIA) interval training sessions in welltrained junior Sprint Kayak athletes. Two different RS training sessions consisting of a shorter 10 s repeat effort session (2 sets of 10 s efforts with 10 s rest between efforts and eight minutes between sets) and a longer 30-s repeat effort session (6 x 30 s efforts with 210 s rest). The HIA sessions included a shorter (2 x 3 min efforts with 3 min rest between efforts, and 5 min between sets) and a longer 2-km (3 x 2 km efforts on a 15 min cycle) interval training sets. The results showed the physiological responses and external loads to the main body the HIA interval sessions were considerably different from RS sessions, with the exception of TSI which was similar for all. Mixed modelling showed significant random variation for the time spent in different training zones for mean power output and ? ̇? O2. The present study highlighted distinct differences in the HR, ? ̇? O2, [BLa], and perceptual responses to common RS and HIA training, with the shorter RS sessions placing a greater stimulus on glycolytic pathways, and the longer HIA sessions requiring greater energetic demands. Importantly, large inter-individual physiological responses were observed across each of the different training sessions. These findings highlight the need to individualise training programs for Sprint Kayak based on the athletes’ characteristics and demands of competition. Study 6: Compared the effects of 5 weeks of RS and HIA interval training on physiological (? ̇? O2max, MAP, LT2, ? ̇? O2kinetics and MO2kinetics) and performance (200 and 1000-m on water time trial) variables in well-trained junior Sprint Kayak athletes using matched-groups randomised design. The groups were matched for physical fitness and on-water kayak performance. In addition to their usual training, the RS training group completed a shorter 10 s repeat effort session (2 sets of 10 s efforts with 10 s rest between efforts and 8 minutes between sets) and longer 30-s repeat effort session (6 x 30 s efforts with 210 s rest), where each session was completed once per week. Similarly, the HIA interval training group completed a three-minute (2 x 3 min efforts with 3 min rest between efforts and 5 min between sets) and longer 2-km aerobic training (3 x 2 km efforts on a 15 min cycle) session once each week during the study in addition to their usual training. Results showed that the RS and HIA interval training interventions elicited trivial changes in maximal indicators of aerobic fitness (i.e. ? ̇? O2max and maximal HR) and trivial and small on-water performance (i.e. time trials over 200 and 1000-m, respectively) in both groups. In contrast, submaximal physiological responses (i.e. lactate threshold) were trivial whereas oxygen kinetics presented small-to-moderate improvements after five weeks (~19 training sessions) performed by both RS and HIA groups. This information suggests that physiological and performance characteristics are very stable in well-trained junior Sprint Kayak athletes. It seems that either larger loads of RS or HIA interval training or longer training periods are required to elicit larger changes in specific physiological adaptations in well-trained junior Sprint Kayak athletes.