Reach-to-grasp movements change quantitatively in a lawful (i.e. predictable) manner with changes in object properties. We explored whether altering object texture would produce qualitative changes in the form of the precontact movement patterns. Twelve participants reached to lift objects from a tabletop. Nine objects were produced, each with one of three grip surface textures (high-friction, medium-friction and low-friction) and one of three widths (50 mm, 70 mm and 90 mm). Each object was placed at three distances (100 mm, 300 mm and 500 mm), representing a total of 27 trial conditions. We observed two distinct movement patterns across all trials--participants either: (i) brought their arm to a stop, secured the object and lifted it from the tabletop; or (ii) grasped the object 'on-the-fly', so it was secured in the hand while the arm was moving. A majority of grasps were on-the-fly when the texture was high-friction and none when the object was low-friction, with medium-friction producing an intermediate proportion. Previous research has shown that the probability of on-the-fly behaviour is a function of grasp surface accuracy constraints. A finger friction rig was used to calculate the coefficients of friction for the objects and these calculations showed that the area available for a stable grasp (the 'functional grasp surface size') increased with surface friction coefficient. Thus, knowledge of functional grasp surface size is required to predict the probability of observing a given qualitative form of grasping in human prehensile behaviour.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3293844 | PMC |
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0032770 | PLOS |
Sci Rep
January 2025
Department of Endocrinology, The Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, China.
This study aimed to identify the correlation of serum 25(OH)D level with sarcopenia and its components in Chinese elderly aged 65 years and above from rural areas. A total of 368 Chinese elderly aged 65 years and above in rural areas were enrolled. Indicators of muscle mass and strength, including the appendicular skeletal muscle mass (ASM), skeletal muscle index (SMI) and hand grip strength (HGS) were measured.
View Article and Find Full Text PDFShock
December 2024
Department of Surgery, University of Texas Medical Branch, Galveston, TX, USA.
Background: Loss of muscle mass and strength in patients who have experienced severe burns is dramatic and associated with subsequent functional impairment. Past work has shown that exercise and oxandrolone, an anabolic steroid, individually improve muscle function and muscle mass in severely burned patients. This study aims to evaluate the effect of oxandrolone treatment combined with resistance exercise on muscle atrophy and investigate the protein synthesis and mitochondrial biogenesis pathways in a hindlimb suspension model.
View Article and Find Full Text PDFAesthet Surg J
January 2025
Department of Dermatology, Erasmus Universiteit Rotterdam, Rotterdam, Netherlands.
Background: Midfacial aging involves skeletal changes, muscle weakening, and fat redistribution, resulting in volume loss, skin sagging, and deepened nasolabial folds. High-Intensity Facial Electrical Stimulation (HIFES) combined with Radiofrequency (RF) is a novel non-invasive method to address these changes by enhancing muscle mass and remodeling subcutaneous tissue.
Objectives: To assess the efficacy of HIFES and Synchronized RF in improving midfacial aesthetics, specifically muscle thickness, skin displacement, and facial volume.
Am J Sports Med
January 2025
Department of Orthopaedics, Lanzhou University Second Hospital, Lanzhou, Gansu, P.R. China.
Background: For patients with osteoporosis and rotator cuff tears, there is still no consensus on current treatment methods. The material, structure, and number of anchors have important effects on the repair outcome.
Purpose: To investigate the use of chitosan quaternary ammonium salt-coated nickel-titanium memory alloy (NTMA) anchors to treat rotator cuff injury in shoulders with osteoporosis in a rabbit osteoporosis model.
Eur J Ophthalmol
January 2025
Cornea and Refractive Surgery Unit, Instituto de Microcirugía Ocular (IMO), Barcelona, 08035, Spain.
Purpose: After 15 years of accumulated experience in the Descemet Membrane Endothelial Keratoplasty (DMEK) technique, this surgical method has demonstrated a high reproducibility and success rate. However, certain ocular conditions such as aphakia and previously vitrectomized eyes remain challenging. We describe a novel technique designed to improve surgical time and postoperative outcomes in these specific scenarios.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!