Purpose: Maximal cycling exercise has been widely used to describe the power-velocity characteristics of lower-limb extensor muscles. This study investigated the contribution of each functional sector (i.e., extension, flexion, and transitions sectors) on the total force produced over a complete pedaling cycle. We also examined the ratio of effective force to the total pedal force, termed index of mechanical effectiveness (IE), in explaining differences in power between subjects.
Methods: Two-dimensional pedal forces and crank angles were measured during a cycling force-velocity test performed by 14 active men. Mean values of forces, power output, and IE over four functional angular sectors were assessed: top = 330 degrees -30 degrees , downstroke = 30 degrees -150 degrees , bottom = 150 degrees -210 degrees , and upstroke = 210 degrees -330 degrees .
Results: Linear and quadratic force-velocity and power-velocity relationships were obtained for downstroke and upstroke. Maximal power output (Pmax) generated over these two sectors represented, respectively, 73.6% +/- 2.6% and 10.3% +/- 1.8% of Pmax assessed over the entire cycle. In the whole group, Pmax over the complete cycle was significantly related to Pmax during the downstroke and upstroke. IE significantly decreased with pedaling rate, especially in bottom and upstroke. There were significant relationships between power output and IE for top and upstroke when the pedaling rate was below or around the optimal value and in all the sectors at very high cadences.
Conclusions: Although data from force-velocity test primarily characterize the muscular function involved in the downstroke phase, they also reflect the flexor muscles' ability to actively pull on the pedal during the upstroke. IE influences the power output in the upstroke phase and near the top dead center, and IE accounts for differences in power between subjects at high pedaling rates.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1249/MSS.0b013e3181c91f35 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Atomically dispersed rare earth dysprosium-nitrogen-carbon for boosting oxygen reduction reaction.
J Colloid Interface Sci
January 2025
Collaborative Innovation Center of Sustainable Energy Materials, School of Physical Science and Technology, Guangxi University, Guangxi Key Laboratory of Electrochemical Energy Materials, State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures, Nanning 530004, China. Electronic address:
Transition metal-nitrogen-carbon (MNC) based on 3d metal atoms as promising non-precious metal catalysts have been extensively exploited for oxygen reduction reaction (ORR), but MNC with 4f rare earth metals have been largely ignored, most likely due to their large atomic radii that are difficult to coordinate with N dopants using conventional precursors. Herein, atomically dispersed dysprosium-nitrogen-carbon (DyNC) nanosheets were developed via the pyrolysis of anitrogen-containing chelate compound of 2, 4, 6-Tri (2-pyridyl) 1, 3, 5-triazine (TPTZ) ligand with Dy under the assistance of molten NaCl. The as-synthesized DyNC features specific moieties of single Dy atom coordinated by N and O as active sites for ORR, displaying excellent performance.
View Article and Find Full Text PDFLighting Up Dual-Aptamer-Based DNA Logic-Gated Series Lamp Probes with Specific Membrane Proteins for Sensitive and Accurate Cancer Cell Identification.
Anal Chem
January 2025
Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, Cixi Biomedical Research Institute, School of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou 325035, China.
Accurate identification of cancer cells under complex physiological environments holds great promise for noninvasive diagnosis and personalized medicine. Herein, we developed dual-aptamer-based DNA logic-gated series lamp probes (Apt-SLP) by coupling a DNA cell-classifier (DCC) with a self-powered signal-amplifier (SSA), enabling rapid and sensitive identification of cancer cells in a blood sample. DCC is endowed with two extended-aptamer based modules for recognizing the two cascade cell membrane receptors and serves as a DNA logic gate to pinpoint a particular and narrow subpopulation of cells from a larger population of similar cells.
View Article and Find Full Text PDFInnovative breast cancer detection using a segmentation-guided ensemble classification framework.
Biomed Eng Lett
January 2025
Electronics and Communication Engineering, IFET College of Engineering, Villupuram, Tamilnadu India.
Unlabelled: Breast cancer (BC) remains a significant global health issue, necessitating innovative methodologies to improve early detection and diagnosis. Despite the existence of intelligent deep learning models, their efficacy is often limited due to the oversight of small-sized masses, leading to false positive and false negative outcomes. This research introduces a novel segmentation-guided classification model developed to increase BC detection accuracy.
View Article and Find Full Text PDFA biofuel cell of (methyl violet/AuNPs)/FTO photoanode and bilirubin oxidase/CuCoO bio-photocathode inspired by the photoelectrochemistry activities of fluorescent materials/molecules.
RSC Adv
January 2025
Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research (Ministry of Education of China), College of Chemistry and Chemical Engineering, Hunan Normal University Changsha 410081 China
Herein, we discuss the idea that fluorescent materials/molecules should logically show potential photoelectrochemistry (PEC) activity, and, in particular, the PEC of fluorescent small molecules (previously usually acting only as dye sensitizers for conventional semiconductors) is explored. After examining the PEC activities of some typical inorganic or organic fluorescent materials/molecules and by adopting methyl violet (MV) with the highest PEC activity among the examined fluorescent small molecules, a new and efficient (MV/Au nanoparticles (AuNPs))/fluorine-doped tin oxide (FTO) photoanode without conventional semiconductor(s) is prepared by layer-by-layer alternating the electrodeposition of AuNPs and the adsorption of MV. A bilirubin oxidase (BOD)/CuCoO/FTO bio-photocathode is prepared by electrodeposition, calcination and cast-coating.
View Article and Find Full Text PDFUltrasonographic evaluation of diaphragm fatigue in healthy humans.
Exp Physiol
January 2025
Division of Sport, Health and Exercise Sciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, UK.
Assessment of diaphragm function and fatigue typically relies on the measurement of transdiaphragmatic pressure (P). Although P serves as an index of diaphragm force output, it provides limited information regarding the ability of the muscle to shorten and generate power. We asked whether ultrasonography, combined with P, could be used to quantify changes in diaphragm function attributable to fatigue.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!