Background: Understanding upper extremity strength symmetry can have important implications for ergonomics assessment and design. Few studies have examined isometric joint strength symmetry of left-handed individuals, or examined how handedness can influence strength. As such, the purpose of this study was to investigate the influence of handedness on dominant/non-dominant (D/ND) strength ratio in several moment directions about the shoulder, elbow, wrist, and hand. It was hypothesized that the isometric strength symmetry of left-handed individuals would be significantly different from that of right-handed individuals.
Methods: The study recruited 28 participants to perform a series of maximal voluntary isometric contractions (MVCs) with both arms for various efforts about the shoulder, elbow, and wrist, as well as handgrip for a total of 68 MVCs. Strength symmetry ratios were computed, and a two-way mixed-model ANOVA evaluated the effects of handedness and MVC test on strength symmetry.
Interpretation: Significant differences in D/ND ratios between right and left-handed individuals were found for 11 of the 17 explored exertion directions. Left-handed individuals tended to possess greater strength in their non-dominant limb, while right-handed individuals tended to have greater strength in their dominant limb. Left- and right-handed individuals often significantly differed in D/ND ratio, suggesting that separate normative values should be created to account for handedness when considering return-to-work or strength-based ergonomics design criterion.
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http://dx.doi.org/10.1016/j.apergo.2023.104133 | DOI Listing |
Phys Rev Lett
December 2024
Donostia International Physics Center, Paseo Manuel de Lardizabal 4, 20018 Donostia-San Sebastian, Spain.
The chiral lattice structure of twisted bilayer graphene with D_{6} symmetry allows for intrinsic photogalvanic effects only at off-normal incidence, while additional extrinsic effects are known to be induced by a substrate or a gate potential. In this Letter, we first compute the intrinsic effects and show they reverse sign at the magic angle, revealing a band inversion at the Γ point. We next consider different extrinsic effects, showing how they can be used to track the strengths of the substrate coupling or electric displacement field.
View Article and Find Full Text PDFAm J Sports Med
January 2025
University of Kentucky, Department of Athletic Training and Clinical Nutrition, Lexington, Kentucky, USA.
Nanomaterials (Basel)
December 2024
Theoretical Physical Chemistry, UR MOLSYS, University of Liege, B4000 Liège, Belgium.
Dynamical symmetries, time-dependent operators that almost commute with the Hamiltonian, extend the role of ordinary symmetries. Motivated by progress in quantum technologies, we illustrate a practical algebraic approach to computing such time-dependent operators. Explicitly we expand them as a linear combination of time-independent operators with time-dependent coefficients.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
South China University of Technology School of Materials Science and Engineering, State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, 381 Wushan Road, 510640, Guangzhou, CHINA.
The exploration of circularly polarized luminescence is important for advancing display and lighting technologies. Herein, by utilizing isomeric molecular engineering, a novel series of chiral molecules are designed to exploit both thermally activated delayed fluorescence (TADF) and room-temperature phosphorescence (RTP) mechanisms for efficient luminescence. The cooperation of a small singlet-triplet energy gap, moderate spin-orbital coupling (SOC), and large oscillator strength enables efficient TADF emission, with photoluminescence quantum yields exceeding 90%.
View Article and Find Full Text PDFX-ray crystal diffraction has provided atomic-level structural information on biological macromolecules. Data quality determines the reliability of structural models. In most cases, multiple data sets are available from different crystals and/or collected with different experimental settings.
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