Purpose: To characterize gender differences in power output, energetic capacity and exercise efficiency during whole-body (WP), upper-body (UP), and arm poling (AP).
Methods: Ten male and ten female elite cross-country skiers, matched for international performance level, completed three incremental submaximal tests and a 3-min self-paced performance test on a Concept2 SkiErg. Power output, cardiorespiratory and kinematic variables were monitored. Body composition was determined by dual-energy X-ray absorptiometry.
Results: The men demonstrated 87, 97 and 103% higher power output, and 51, 65 and 71% higher VO2peak (L min(−1)) than the women during WP, UP and AP, respectively, while utilizing ~10% more of their running VO2max in all modes (all P < 0.001). The men had 35, 38 and 59% more lean mass in the whole body, upper body and arms (all P < 0.001). The men exhibited greater shoulder and elbow extension at the start of poling and greater trunk flexion at the end of poling (all P < 0.05). The relationship between VO2 and power output did not differ between the men and women.
Conclusions: Gender differences in power production and peak aerobic capacity increased sequentially from WP to UP to AP, coinciding with a greater portion of the muscle mass in the arms of the men. Although the men and women employed each poling technique differently, the estimated efficiency of double poling was independent of gender.
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http://dx.doi.org/10.1007/s00421-015-3281-y | DOI Listing |
J Appl Physiol (1985)
January 2025
Department of Human Physiology, Gonzaga University, Spokane, Washington, United States.
We tested the hypothesis that power at maximal metabolic steady state is similar between fitness matched men and women. Eighteen participants (9 men, 9 women) performed a cycling graded exercise test for maximal oxygen consumption (V̇O). Men and women were matched for V̇O normalized to fat free mass (FFM), which was 50.
View Article and Find Full Text PDFSci Adv
January 2025
Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC, USA.
A recurring challenge in extracting energy from ambient motion is that devices must maintain high harvesting efficiency and a positive user experience when the interface is undergoing dynamic compression. We show that small amphiphiles can be used to tune friction, haptics, and triboelectric properties by assembling into specific conformations on the surfaces of materials. Molecules that form multiple slip planes under pressure, especially through π-π stacking, produce 80 to 90% lower friction than those that form disordered mesostructures.
View Article and Find Full Text PDFSci Adv
January 2025
NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa, Italy.
While piezoelectric sensing and energy-harvesting devices still largely rely on inorganic components, biocompatible and biodegradable piezoelectric materials, such as cellulose nanocrystals, might constitute optimal and sustainable building blocks for a variety of applications in electronics and transient implants. To this aim, however, effective methods are needed to position cellulose nanocrystals in large and high-performance architectures. Here, we report on scalable assemblies of cellulose nanocrystals in multilayered piezoelectric systems with exceptional response, for various application scopes.
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January 2025
Department of Applied Physics and Integrated Education Institute for Frontier Science and Technology (BK21 Four), Kyung Hee University, Yongin 17104, Korea.
One-dimensional (1D) vertical nitrides are highly attractive for light-emitting diode (LED) applications because they are useful for overcoming the drawbacks of conventional GaN planar structures. However, the internal quantum efficiency (IQE) of GaN multi-quantum-well (MQW) nanowire (NW) LEDs, typical 1D GaN structures, is still too low to replace standard planar LEDs. Here, we report a phenomenon of light amplification from core-shell InGaN/GaN NW LEDs by incorporating graphene quantum dots (GQDs).
View Article and Find Full Text PDFPLoS One
January 2025
Centre National de la Recherche Scientifique, Institut des Sciences du Mouvement, Aix-Marseille Univ, Marseille, France.
Little is known about the influence of fatigue in repeated overground sprinting on force-velocity properties in children and adolescents, while this ability to repeat sprints is important for future progress in rugby union. Sprint time decline is commonly used to assess fatigability. However, it does not provide data on biomechanical aspects of sprint performance such as maximal power, force, and velocity production.
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