Objectives: This study aimed to report (1) the correlation between net metabolic cost (NMC) of running and Achilles tendon (AT) and ankle plantar flexor passive stiffness and (2) explore the relationship between passive stiffness and key running biomechanics.
Methods: Twenty-two male recreational runners participated in this study. The runners performed a 5-minute run at 50% of their maximal aerobic speed as a warm-up on an instrumented treadmill, followed by a 6-minute run at 65% of their maximal aerobic speed wherein NMC was recorded. Passive stiffness was measured using a myotonometry device both before and after the run.
Results: There was a negative linear relationship between NMC and AT stiffness. NMC and prerun AT stiffness demonstrated a significant negative correlation between leg stiffness and a significant positive correlation with braking peak force and step length. Moreover, we observed an increase in stiffness between prerun and postrun measurements at rest for the AT and both gastrocnemius muscles.
Conclusion: Greater AT stiffness measured at rest is correlated with lower NMC.
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http://dx.doi.org/10.1123/ijspp.2024-0375 | DOI Listing |
Wearable Technol
March 2025
Department of GMSC, Pprime Institute CNRS, UPR 3346, ISEA-ENSMA, University of Poitiers, Poitiers, France.
This article presents a bioinspired pneumatic soft actuator designed to mimic the flexo-extension movement of the human finger, with a particular focus on stiffness modulation through granular jamming. Three-chamber geometries - honeycomb, rectangular, and half-round - were evaluated to optimize curvature performance, utilizing Mold Star 15 Slow elastomer for actuator fabrication. Granular jamming, both passive and active, was implemented within the inextensible layer using chia and quinoa grains to enhance stiffness modulation.
View Article and Find Full Text PDFAnn N Y Acad Sci
March 2025
Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA.
A surgeon peers downward into a body cavity when operating. Holding this position for hours across weeks, months, and years may lead to neck pain and musculoskeletal disorders. We were inspired by ungulates such as giraffes and horses, which use dorsal-ventral flexion to graze for 9-14 h per day without perceivable neck pain.
View Article and Find Full Text PDFAm J Physiol Heart Circ Physiol
March 2025
Biomedical Engineering Program, College of Engineering and Computing, University of South Carolina, Columbia, SC 29201.
Endothelial dysfunction, defined as a reduction in the bioavailability of nitric oxide (NO), is a risk factor for the occurrence and progression of various vascular diseases. This study investigates the effect of endothelial dysfunction on age-related changes in aortic extracellular matrix (ECM) microstructure and the relationship between microstructural adaptation and the mechanical response. Here, we used groups of NOS3 knockout (KO), NOS3 heterozygotes (Het), and wild type (WT) B6 mice (controls) to study changes in hemodynamic parameters, collagen fiber organization, and both active and passive aortic mechanics using biaxial pressure myography over a time course from 1.
View Article and Find Full Text PDFJ Gen Physiol
May 2025
Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary.
Marfan syndrome (MFS) is an autosomal dominant disease caused by mutations in the gene (FBN1) of fibrillin-1, a major determinant of the extracellular matrix (ECM). Functional impairment in the cardiac left ventricle (LV) of these patients is usually a consequence of aortic valve disease. However, LV passive stiffness may also be affected by chronic changes in mechanical load and ECM dysfunction.
View Article and Find Full Text PDFMyocardial Infarction (MI) is a major contributor to morbidity and mortality, wherein blood flow is blocked to a portion of the left ventricle and leads to myocardial necrosis and scar formation. Cardiac remodeling in response to MI is a major determinant of patient prognosis, so many therapies are under development to improve infarct healing. Part of this development involves in vitro therapy screening which can be accelerated by engineered heart tissues (EHTs).
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!