Muscle forces determine joint loads, but the objectives governing the mix of muscle forces involved are unknown. This study tested the hypothesis that masticatory muscle forces exerted during static biting are consistent with objectives of minimization of joint loads (MJL) or muscle effort (MME). To do this, we compared numerical model predictions with data measured from six subjects. Biting tasks which produced moments on molar and incisor teeth were modeled based on MJL or MME. The slope of predicted vs. electromyographic (EMG) data for an individual was compared with a perfect match slope of 1.00. Predictions based on MME matched best with EMG activity for molar biting (slopes, 0.89-1.16). Predictions from either or both models matched EMG results for incisor biting (best-match slopes, 0.95-1.07). Muscle forces during isometric biting appear to be consistent with objectives of MJL or MME, depending on the individual, biting location, and moment.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1177/154405910308200312 | DOI Listing |
Exp Physiol
January 2025
Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.
This study investigated how contraction frequency impacts the mechano-energetics of cardiac muscle performing mechanical work. Left-ventricular trabeculae were isolated from rat hearts and mounted in our work-loop calorimeter to assess their function at physiological temperature (37°C) across three stimulation frequencies, 2 Hz, 3.5 Hz and 5 Hz, in a randomised sequence.
View Article and Find Full Text PDFJ Cachexia Sarcopenia Muscle
February 2025
Musculoskeletal Research Laboratory, Department of Orthopedics & Traumatology, The Chinese University of Hong Kong, Hong Kong, China.
Background: Regenerative capacity of skeletal muscles decreases with age. Deficiency in cystic fibrosis transmembrane conductance regulator (CFTR) is associated with skeletal muscle weakness as well as epithelial cell senescence. However, whether and how CFTR plays a role in skeletal muscle regeneration and aging were unclear.
View Article and Find Full Text PDFJ Exp Zool A Ecol Integr Physiol
January 2025
Department of Biology, University of Akron, Akron, Ohio, USA.
Escape responses are vital for the survival of prey. The high speeds and accelerations needed to evade predators successfully require exerting forces on the environment. Unlike water, terrestrial habitats can vary in ways that constrain the forces applied, requiring animals to adjust their behavior in response to variable conditions.
View Article and Find Full Text PDFEur J Sport Sci
February 2025
Department of Sport Science, Chair for Health and Physical Activity, Otto-von-Guericke University Magdeburg, Magdeburg, Germany.
This study aimed to examine the acute effects of concurrent muscle strength and sport-specific endurance exercise order on immunological stress responses, metabolic response, muscular-fitness, and rating-of-perceived-exertion (RPE) in highly trained youth female judo athletes. Thirteen female participants randomly performed two concurrent training (CT) sessions; strength-endurance and endurance-strength. Immune response, metabolic response, muscular fitness (i.
View Article and Find Full Text PDFBackground: Previous studies have suggested that changes in the composition of the extracellular matrix (ECM) play a significant role in the development of ligamentum flavum hypertrophy (LFH) and the histological differences between the ventral and dorsal layers of the hypertrophied ligamentum flavum. Although LFH is associated with increased fibrosis in the dorsal layer, comprehensive research exploring the characteristics of the ECM and its mechanical properties in both regions is limited. Furthermore, the distribution of fibrosis-associated myofibroblasts within LFH remains poorly understood.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!