Mean maximal power from an on-water 1000-m time-trial predicts lactate threshold power in well-trained flat-water sprint kayak athletes

Abstract

This study utilised on-water graded exercise tests (GXT) to determine the power output (PO) corresponding to the first and second lactate thresholds (LT₁PO and LT₂PO), subsequently examining their relationship to the mean maximal power (MMP) and race time achieved across three on-water sprint kayak time-trials. Twelve well-trained sprint kayak athletes completed an on-water GXT and a 200-, 500- and 1000-m time-trial utilising novel instrumented paddle technology. Stepwise multiple regression was used to determine whether equations incorporating 200-, 500- and 1000-m MMP data could be used as an alternative method for estimating LT₁PO and LT₂PO. On-water GXT derived LT₁PO and LT₂PO were 151 ± 34 and 194 ± 39 W, respectively. For the 200-, 500- and 1000-m time-trials, MMP were 528 ± 143, 358 ± 92 and 287 ± 67 W, respectively. Athletes' LT₁PO and LT₂PO had very-large inverse relationships to 200-, 500- and 1000-m time-to-completion (r = -.71 to -.85, P ≤ .010) and very-large, to near-perfect positive relationships to 200-, 500- and 1000-m MMP (r = .81 to .94, P ≤ .001). The equation incorporating 1000-m MMP alone provided the best prediction of LT₁PO and LT₂PO, explaining 78% and 88% of the variance, and yielding a standard error of estimate (SEE) of 11.3% and 7.1% for these measures, respectively. The results of this study provide further evidence to support the ecological validity of recently developed on-water GXTs graded by PO, since LT₁PO and LT₂PO were significantly correlated to 200-, 500- and 1000-m performance. Practitioners could also predict LT₂PO with reasonable accuracy based solely from a 1000-m time-trial; potentially providing an alternative, non-invasive, competition-specific protocol for threshold determination.HighlightsThe fact that LT1PO and LT2PO had very-large, to near-perfect positive relationships to 200-, 500- and 1000-m MMP suggests that coaches should consider these relative submaximal aerobic-fitness variables when evaluating the performance of sprint kayak athletes, regardless of their race specialty.While the SEE and 95% limits of agreement (95%LoA) values for the prediction of LT₁PO may be too large to be practically meaningful, measures of LT₂PO could be predicted with a reasonable level of accuracy based upon 1000-m MMP.The ability to inform athletes' LT₂PO from a single 1000-m time-trial is advantageous since it would provide a more feasible, and time-efficient testing protocol within the athletes' training schedule compared to GXTs, potentially allowing coaches and practitioners to monitor changes in LT₂PO, and subsequently review individual training zones, more regularly.Given that LT₁PO and LT₂PO derived from on-water GXTs had very-large, to nearly perfect relationships to 200-, 500- and 1000-m performance, practitioners may prefer to use on-water, rather than laboratory-based GXTs given their greater practical significance and ecological validity.

Keywords: Power output; graded exercise test; testing; time trials; training.