Lactate, HR and RPE responses of elite surf lifesavers to carnival competition
Conference Contribution ResearchOnline@JCUAbstract
Introduction: Previous research has investigated the physiological, anthropometric (Gulbin et al. 1996) and metabolic demands of elite surf lifesavers under field-based assessment and simulated competition performance (Rice et al. 2004). To date no in-competition information has been available. A surf carnival will run from 2-4 d and include multiple individual and team events. The individual disciplines include beach flags, beach sprinting, surf swimming (SWIM), Malibu surfboard paddling (BOARD), surf ski paddling and ironman and ironwoman (IRON) events. Research investigating the metabolic demands of a simulated IRON race reported athletes exhibiting near maximal heart rates and blood lactate concentration despite a relatively low perception of effort (Rice et al. 2004). However, during surf carnivals elite surf lifesavers are required to compete in multiple rounds (heats, semi-finals and finals) for a variety of disciplines in both individual and team events across 2-4 d. Therefore the purpose of this project was to investigate the metabolic demands on elite surf lifesavers competing in a major surf carnival. Methods: Elite surf lifesavers (8 male, 5 female; age 21.9 ± 4.0 yr) from the 2005-2006 Surf Life Saving Australia National High Performance Program competed in team and individual events at a Summer Surf Series carnival. Baseline blood lactate (La) assessments were conducted the evening prior to the carnival. During the carnival, athletes provided an ear-prick blood sample 2-3min following the completion of individual events for La analysis. Rating of perceived exertion (RPE) and HR via telemetry were obtained following the event. Events assessed included SWIM, BOARD and IRON races. SWIM consisted of athletes entering the water from the beach, swimming out to and around a string of buoys and returning to shore (~460 m). BOARD consisted of entering the water, paddling out to and around buoys and returning to shore (~550 m). IRON consisted of consecutive SWIM (~280 m), BOARD (~380 m) and surf ski legs (~510 m) interspersed with intermittent run legs (~70 m). Written informed consent was obtained prior to testing in accordance with the James Cook University Human Sub-Ethics Committee. Analysis of IRON and BOARD was conducted via repeated measures ANOVA (heats vs. semi-finals vs. final) while paired samples T-tests were used for SWIM analysis (semi-finals vs. final). Only SWIM semi-finals (males only) and final (males and females) were contested due to limited numbers. Analysis per round between disciplines was conducted via a one-way ANOVA. Alpha was set at 0.05. Results: IRON and BOARD results across the heats, semi-finals and final are presented in Table 1. No significant differences were identified for SWIM post-exercise La between the semi-finals (8.43 ± 3.62 mmol•L-1) and final (9.20 ± 3.99 mmol•L-1). Comparison between disciplines identified no significant differences for post-exercise La, RPE or HR between the semi-finals and final rounds for IRON, SWIM and BOARD disciplines or between BOARD and IRON disciplines for the heat rounds. Table 1: Mean (SD) RPE, HR and post La for IRON and BOARD for heats, semi-finals and finals IRON (n=5) BOARD (n=6) Heats Semi-finals Final Heats Semi-finals Final RPE 12 (2) 15 (1) 19 (0)ab 12 (1) 15 (2) 15 (3) HR (b•min-1) 142 (17) 155 (10) 171 (9)ab 133 (17) 153 (22)a 159 (20)a Post La (mmol•L-1) 5.84 (3.63) 8.58 (1.51) 10.54 (2.75)a 4.70 (2.35) 5.93 (1.93) 9.01 (2.82)a ap<0.05 greater than heats; bp<0.05 greater than semi-finals Discussion/Conclusion: The results suggest that elite surf lifesavers express similar physiological responses during each round of the IRON and BOARD disciplines. The greater HR and post La responses in the IRON and BOARD finals compared with the semi-finals and heats, suggest similar pacing strategies were used to progress through lower rounds of these events. However, pacing was not evident during the SWIM rounds where the semi-finals were contested at the same metabolic demand required for the final. Therefore, while IRON and BOARD competitors may focus on pacing strategies during the lower rounds, SWIM competitors need to optimise recovery strategies between rounds. Despite IRON races being considerably longer duration than both SWIM and BOARD, the metabolic demands on the athlete in the final races are similar between each discipline. References Gulbin JP, Fell JW, Gaffney PT. Australian Journal of Science & Medicine in Sport (1996). 28(3):86-90. Rice A, et al. http://slsaasnau.ozhosting.com/doc_display.asp?document_id=192 (2004).
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Proceedings of the 2nd Australian association for exercise and sport science conference and the 4th sports dietitians australia update
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2
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978-0-646-46536-4
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1
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Sydney, NSW, Australia
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University of New South Wales Press
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