Associations Between Lactate Thresholds and 2000 m Rowing Ergometer Performance: Implications for Prediction-A Systematic Review.

Background: Various exercise thresholds have been evaluated to predict athlete performance. However, a systematic review of the literature assessing the association between lactate-based exercise thresholds and 2000 m rowing ergometer performance is still lacking. These may have utility in the prediction of 2000 m rowing ergometer performance due to the close relationship between metabolic parameters and development of endurance capacity. The aim of the present study is to review and assess the extent, quality, and reliability of lactate-based exercise testing and methodologies in their association with 2000 m rowing ergometer performance, and to discuss the potential implications for performance prediction.

Methods: The systematic review was performed following PRISMA 2020 guidelines. The databases searched were EMBASE, MEDLINE and SPORTDiscus. The initial search took place in July 2022, with an update search performed in September 2023, and again in August 2024. Studies which reported a lactate test and its correlation to 2000 m ergometer performance were included. No meta-analysis was performed.

Results: Twenty-four studies comprising 797 athletes (513 male, 257 female, 27 not stated) met the eligibility criteria for inclusion in the review. The most commonly used testing protocol involved the use of incremental step-tests. A range of exercise intensity parameters, lactate-based exercise thresholds and interpretation methodologies were employed. Of these, the power or velocity at a blood lactate concentration of 4 mmol l^-1 was the most common test, with correlation coefficients ranging from 0.53 to 0.96 suggesting that 28-92% of the variance in rowing performance can be explained by this metric. Six studies that rated as GOOD on the risk of bias assessment found very strong correlations > 0.85 (p < 0.05).

Conclusions: This systematic review found that there is good evidence that the power generated at a blood lactate concentration of 4 mmol l^-1 correlates strongly to 2000 m rowing ergometer performance and may have useful predictive power. However, the review also identified the varying quality of the available literature, with a variety of parameters, exercise protocols, testing methods, and performance metrics being used to report performance making it difficult to compare results between studies. Other tests such as $\dot{V}{O}_2$ at a blood lactate concentration of 4 mmol l^-1 and power at the initial non-linear inflection blood lactate threshold merit further investigation as the extent and reliability of the available data is currently insufficient to draw firm conclusions.

Protocol registration: The protocol was registered on Open Science Framework on 17/11/2022. https://doi.org/10.17605/OSF.IO/D8YCE.