What is the physiological impact of reducing the 2,000 m Olympic distance in rowing to 1,500 m and 1,000 m for French young competitive rowers? Insights from the energy system contribution

© 2022 The Authors. Published by Frontiers Media. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.3389/fphys.2022.896975French rowing federation reduced the competition distance to 1,500 and 1,000 m in rowers under 16- (U16) and 14-year-old (U14) respectively, to prepare them progressively to the Olympic 2,000 m distance in under 18-year-old (U18). This study aimed to check the hypothesis that relative aerobic (%EAe) and anaerobic (%EAn) energy contributions would be comparable between the competition distances since the more oxidative profile of younger age categories could offset the greater anaerobic contribution induced by shorter rowing races. Thirty-one 12- to 17-year-old competitive rowers performed a race of 2,000, 1,500, or 1,000 m on a rowing ergometer according to their age category. %EAe and %EAn were estimated from oxygen consumption, changes in blood lactate concentration and their energy equivalents. %EAe was lower in U16 than U18 (84.7 vs. 87.0%, p < 0.01), and in U14 than U16 (80.6 vs. 84.7%, p < 0.001). %EAn was higher in U16 than U18 (15.3 vs. 13.0%, p < 0.01), and in U14 than U16 (19.4 vs. 15.3%, p < 0.01). The results did not confirm our initial hypothesis since %EAe and %EAn were significantly different between the race distances, and thus age categories. However, %EAn in U18, U16 and U14 were found to be in the range of values previously found in adult rowers over the 2,000 m Olympic distance (12–30%). Therefore, on a practical level, the strategy implemented by the French rowing federation to reduce the competition distance in the younger age categories could be relevant to progressively prepare them to the physiological requirements encountered over the Olympic distance.This study was carried out in collaboration with the laboratory Sport, Expertise and Performance (EA 7370) of the French Institute of Sport (INSEP, Paris).Published onlin

Sex-Related Differences in Oxygen Consumption Recovery After High-Intensity Rowing Exercise During Childhood and Adolescence

Purpose: To determine sex-related differences in oxygen consumption ( ) recovery after high-intensity exercise during childhood and adolescence. Methods : Forty-two boys and 35 girls (10–17 y) performed a 60-second all-out test on a rowing ergometer. Postexercise recovery was analyzed from (1) the recovery time constant obtained from a biexponential model (τ1 ) and (2) excess postexercise oxygen consumption calculated over a period of 8 minutes (EPOC 8 ) and until τ 1 was reached (EPOC τ 1 ). Multiplicative allometric modeling was used to assess the concurrent effects of body mass or lean body mass, and age on EPOC 8 and EPOC τ 1 . Results: EPOC 8 increased significantly more in boys from the age of 14 years. However, the sex difference was no longer significant when EPOC 8 was analyzed using an allometric model including body mass + age or lean body mass + age. In addition, despite a greater increase in EPOC τ 1 in boys from the age of 14 years, τ 1 was not significantly different between sexes whatever age. Conclusion: While age and lean body mass accounted for the sex-related differences of EPOC during childhood and adolescence, no significant effect of age and sex was observed on the recovery time constant after high-intensity exercise

Sex-related differences in accumulated O2 deficit incurred by high-intensity rowing exercise during childhood and adolescence

International audiencePurpose :The aims of the present study were to determine during childhood and adolescence (i) the effect of sex on non-oxidative energy production, quantified by the accumulated oxygen deficit (AOD), and (ii) the influence of AOD on high-intensity performance.Methods :Thirty-nine boys and 35 girls aged 10–17 years performed a 60 s all-out test on a rowing ergometer to determine AOD and mean power output (MPO). Multiplicative allometric modelling was used to assess the concurrent effects of lean body mass (LBM) and age on AOD.Results :AOD significantly increased with age in both sexes (p Conclusion :Non-oxidative energy production increased more extensively in boys than girls from the age of 14 years. Age and LBM accounted for the sexual differentiation of AOD during childhood and adolescence. In addition, AOD was found to be a determinant factor of high-intensity performance, more particularly in boys

Sex‐ and age‐related differences in the rating of perceived exertion after high‐intensity rowing exercise during childhood and adolescence

International audienceAbstract The present study aimed to evaluate the effects of age and sex on the rating of perceived exertion (RPE) during high‐intensity exercise and determine whether mechanical and physiological parameters could be predictors of RPE during childhood and adolescence. Forty‐three boys and 36 girls performed a 60‐s all‐out test on a rowing ergometer and were categorized by age group (10.0–11.9; 12.0–13.9; 14.0–15.9; 16.0–17.9 years) and sex. Ratings of perceived exertion were assessed using the 6–20 RPE and CR‐10 scales and analyzed with respect to mechanical work rate (W tot ), post‐exercise peak blood lactate concentration ([La] peak ), and peak minute ventilation (V̇E peak ). Multilevel regression modeling revealed a significant influence of W tot , [La] peak and V̇E peak on 6–20 RPE and CR‐10 scores ( r 2 = .34 and .36, p < .001, respectively). However, while boys perceived high‐intensity exercise as being subjectively more difficult than girls at all ages ( p < .05) except 12.0–13.9 years, significant higher mechanical work rate and greater associated metabolic responses in boys than girls were only found from the age of 14 years (W tot and V̇E peak ) or 16 years ([La] peak ), suggesting that the association between RPE and mechanical/physiological parameters could not be held before the age of 12 years. To conclude, RPE increased with increasing age, with boys exhibiting higher scores than girls at all ages except 12.0–13.9 years. This finding is probably explained by the higher W tot and greater concomitant metabolic responses in boys at the time of puberty. However, other factors should be considered at least in children before the age of 12 years

Importance of dimensional changes on glycolytic metabolism during growth

International audiencePurposeThe aim of the present study was to investigate (i) how glycolytic metabolism assessed by accumulated oxygen deficit (AODgly) and blood metabolic responses (lactate and pH) resulting from high-intensity exercise change during growth, and (ii) how lean body mass (LBM) influences AODgly and its relationship with blood markers.MethodsThirty-six 11- to 17-year olds performed a 60-s all-out test on a rowing ergometer. Allometric modelling was used to investigate the influence of LBM and LBM + maturity offset (MO) on AODgly and its relationship with the extreme post-exercise blood values of lactate ([La]max) and pH (pHmin) obtained during the recovery period.ResultsAODgly and [La]max increased while pHmin decreased linearly with LBM and MO (r2 = 0.46 to 0.72, p < 0.001). Moreover, AODgly was positively correlated with [La]max (r2 = 0.75, p < 0.001) and negatively correlated with pHmin (r2 = 0.77, p < 0.001). When AODgly was scaled for LBM, the coefficients of the relationships with blood markers drastically decreased by three to four times ([La]max: r2 = 0.24, p = 0.002; pHmin: r2 = 0.30, p < 0.001). Furthermore, by scaling AODgly for LBM + MO, the correlation coefficients with blood markers became even lower ([La]max: r2 = 0.12, p = 0.037; pHmin: r2 = 0.18, p = 0.009). However, MO-related additional changes accounted much less than LBM for the relationships between AODgly and blood markers

Towards the industrialization of solid-state batteries: Impact of dry room exposure on sulfide-based solid electrolyte materials

International audienc

Towards the industrialization of solid-state batteries: Impact of dry room exposure on sulfide-based solid electrolyte materials

International audienc

Towards a practical use of sulfide solid electrolytes in all-solid-state-batteries: Impact of dry room exposure on H2S release and material properties

International audienceAll-solid-state-batteries studies have increased steadily over the past few years. One family of materials gaining particular attention are the moisture sensitive sulfide solid electrolytes, mostly because of their impressive ionic conductivity and their cyclability in lithium-based batteries. Even though we witness a strong interest from batteries and cars manufacturers leading to several partnerships to accelerate the technology development, the literature is mostly dominated by lab scale concerns. In most studies, solid-state-batteries are manufactured in a glove box in order to prevent the exposition of solid electrolytes to moisture. Herein, we propose a study on three sulfide electrolytes, namely in-house Li7P3S11 and Li5.8PS4.8Cl1.2 along with commercial Li6PS5Cl, in a dry room environment (dew point = -40 °C), in order to elucidate 1. the safe handling of sulfide electrolytes regarding its propensity to generate H2S and 2. the resulting material properties after dry room exposure thanks to a set of characterization techniques including X-ray diffraction, Raman spectroscopy, electrochemical impedance spectroscopy, scanning electron microscopy and X-ray photoelectron spectrometry to hypothesize the potential degradation mechanisms occurring at the particle surface. Finally, galvanostatic cycling of Li0.38In0.62-NMC622 cells will be presented to assess the impact of dry room exposure on cell performance. This work is fundamental to any research projects aiming to find suitable processes to manufacture sulfide-based solid-state-batteries at larger scale

Towards a practical use of sulfide solid electrolytes in all-solid-state-batteries: Impact of dry room exposure on H2S release and material properties

International audienceAll-solid-state-batteries studies have increased steadily over the past few years. One family of materials gaining particular attention are the moisture sensitive sulfide solid electrolytes, mostly because of their impressive ionic conductivity and their cyclability in lithium-based batteries. Even though we witness a strong interest from batteries and cars manufacturers leading to several partnerships to accelerate the technology development, the literature is mostly dominated by lab scale concerns. In most studies, solid-state-batteries are manufactured in a glove box in order to prevent the exposition of solid electrolytes to moisture. Herein, we propose a study on three sulfide electrolytes, namely in-house Li7P3S11 and Li5.8PS4.8Cl1.2 along with commercial Li6PS5Cl, in a dry room environment (dew point = -40 °C), in order to elucidate 1. the safe handling of sulfide electrolytes regarding its propensity to generate H2S and 2. the resulting material properties after dry room exposure thanks to a set of characterization techniques including X-ray diffraction, Raman spectroscopy, electrochemical impedance spectroscopy, scanning electron microscopy and X-ray photoelectron spectrometry to hypothesize the potential degradation mechanisms occurring at the particle surface. Finally, galvanostatic cycling of Li0.38In0.62-NMC622 cells will be presented to assess the impact of dry room exposure on cell performance. This work is fundamental to any research projects aiming to find suitable processes to manufacture sulfide-based solid-state-batteries at larger scale