The aim of this study was to propose a new index called Postural Force Production Index (PFPI) for evaluating the force production during handcycling. For a given posture, it assesses the force generation capacity in all Cartesian directions by linking the joint configuration to the effective force applied on the handgrips. Its purpose is to give insight into the force pattern of handcycling users, and could be used as ergonomic index. The PFPI is based on the force ellipsoid, which belongs to the class of manipulability indices and represents the overall force production capabilities at the hand in all Cartesian directions from unit joint torques. The kinematics and kinetics of the arm were recorded during a 1-min exercise test on a handcycle at 70 revolutions per minute performed by one paraplegic expert in handcycling. The PFPI values were compared with the Fraction Effective Force (FEF), which is classically associated with the effectiveness of force application. The results showed a correspondence in the propulsion cycle between FEF peaks and the most favorable postures to produce a force tangential to the crank rotation (PFPI). This preliminary study opens a promising way to study patterns of force production in the framework of handcycling movement analysis.
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http://dx.doi.org/10.1123/jab.29.6.798 | DOI Listing |
J Biomed Mater Res B Appl Biomater
January 2025
Department and Research Institute of Dental Biomaterials and Bioengineering, Yonsei University College of Dentistry, Seoul, Republic of Korea.
Addressing the high cost and long cycle associated with the multistep digital restoration process involving 3D printing technology, we proposed the 3D pen as an innovative strategy for rapid bone repair. Capitalizing on the low melting point characteristic of polycaprolactone (PCL), we introduced, for the first time, the novel concept of directly constructing scaffolds at bone defect sites using 3D pens. In this in vitro study, we meticulously evaluated both the mechanical and biological properties of 3D pen-printed PCL scaffolds with six distinct textures: unidirectional (UNI) (0°, 45°, 90°), bidirectional (BID) (-45°/45°, 0°/90°), and concentric (CON).
View Article and Find Full Text PDFLangmuir
January 2025
Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, Műegyetem rkp. 3, 1111 Budapest, Hungary.
During the experimental formation of sol-gel coatings, the colloid dispersions go through a drying process, and the structure of the coatings is formed as a result of complex chemical, colloidal, and capillary interactions. While computer simulations provide guidelines to tune and even design the nanomaterials synthesis, simulations of coating structure formation are hitherto unknown in the literature. Based on real experiments, we establish here a ReaxFF reactive force field-based molecular dynamics simulation protocol in order to investigate and determine the role of the experimental conditions on the pore structure formation in the coatings.
View Article and Find Full Text PDFACS Appl Eng Mater
December 2024
Department of Chemistry and Biochemistry, Rowan University, Glassboro, New Jersey 08028, United States.
Carbon-based nanofibers are critical materials with broad applications in industries such as energy, filtration, and biomedical devices. Polyacrylonitrile (PAN) is a primary precursor for carbon nanofibers, but conventional electrospinning techniques typically operate at low production rates of 0.1-1 mL/h from a single spinneret, limiting scalability.
View Article and Find Full Text PDFFront Pharmacol
December 2024
Feinberg School of Medicine, Northwestern University, Chicago, United States.
Nature
January 2025
Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA.
The forces generated by action potentials in muscle cells shuttle blood, food and waste products throughout the luminal structures of the body. Although non-invasive electrophysiological techniques exist, most mechanosensors cannot access luminal structures non-invasively. Here we introduce non-toxic ingestible mechanosensors to enable the quantitative study of luminal forces and apply them to study feeding in living Caenorhabditis elegans roundworms.
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