A Maximal Rowing-Ergometer Protocol to Predict Maximal Oxygen Uptake in Female Rowers.

BACKGROUND: Laboratory assessment of maximal oxygen uptake (V˙O2max) is physically and mentally draining for the athlete and requires expensive laboratory equipment. Indirect measurement of V˙O2max could provide a practical alternative to laboratory testing. PURPOSE: To examine the relationship between the maximal power output (MPO) in an individualized 7 × 2-minute incremental test (INCR-test) and V˙O2max and to develop a regression equation to predict V˙O2max from MPO in female rowers. METHODS: Twenty female club and Olympic rowers (development group) performed the INCR-test on a Concept2 rowing ergometer to determine V˙O2max and MPO. A linear regression analysis was used to develop a prediction of V˙O2max from MPO. Cross-validation analysis of the prediction equation was performed using an independent sample of 10 female rowers (validation group). RESULTS: A high correlation coefficient (r = .94) was found between MPO and V˙O2max. The following prediction equation was developed: V˙O2max (mL·min-1) = 9.58 × MPO (W) + 958. No difference was found between the mean predicted V˙O2max in the INCR-test (3480 mL·min-1) and the measured V˙O2max (3530 mL·min-1). The standard error of estimate was 162 mL·min-1, and the percentage standard error of estimate was 4.6%. The prediction model only including MPO, determined during the INCR-test, explained 89% of the variability in V˙O2max. CONCLUSION: The INCR-test is a practical and accessible alternative to laboratory testing of V˙O2max.

Abundance and distribution of microplastics in surface waters of the Kattegat/ Skagerrak (Denmark).

Microplastics (MPs) are ubiquitous pollutants in the ocean, and there is a general concern about their persistence and potential effects on marine ecosystems. We still know little about the smaller size-fraction of marine MPs (MPs <300 µm), which are not collected with standard nets for MPs monitoring (e.g., Manta net). This study aims to determine the concentration, composition, and size distribution of MPs down to 10 µm in the Kattegat/Skagerrak area. Surface water samples were collected at fourteen stations using a plastic-free pump-filter device (UFO sampler) in October 2020. The samples were treated with an enzymatic-oxidative method and analyzed using FPA-µFTIR imaging. MPs concentrations ranged between 11 and 87 MP m-3, with 88% of the MPs being smaller than 300 µm. The most abundant shape of MPs were fragments (56%), and polyester, polypropylene, and polyethylene were the dominant synthetic polymer types. The concentration of MPs shows a significant positive correlation to the seawater density. Furthermore, there was a tendency towards higher MPs concentrations in the Northern and the Southern parts of the study area. The concentration of MPs collected with the UFO sampler was several orders of magnitude higher than those commonly found in samples collected with the Manta net due to the dominance of MP smaller size fractions. Despite the multiple potential sources of MPs in the study area, the level of MPs pollution in the surface waters was low compared (<100 MP m-3) to other regions. The concentrations of MPs found in the studied surface waters were six orders of magnitude lower than those causing negative effects on pelagic organisms based on laboratory exposure studies, thus is not expected to cause any impact on the pelagic food web.