Although it is now understood that trained skeletal muscle can generate enough steady-state power to provide significant circulatory support, there are currently no means by which to tap this endogenous energy source to aid the failing heart. To that end, an implantable muscle energy converter (MEC) has been constructed and its function has been improved to optimize durability, anatomic fit, and mechanical efficiency. Bench tests show that MEC transmission losses average less than 10% of total work input and that about 85% of this muscle power is successfully transferred to the working fluid of the pump. Results from canine implant trials confirm excellent biocompatibility and demonstrate that contractile work of the latissimus dorsi muscle-measured to 290 mJ/stroke in one dog-can be transmitted within the body at levels consistent with cardiac assist requirements. These findings suggest that muscle-powered cardiac assist devices are feasible and that efforts to further develop this technology are warranted.
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http://dx.doi.org/10.1111/j.1525-1594.2005.29108.x | DOI Listing |
J Appl Biomech
January 2025
J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA.
The metabolic cost of walking for individuals with transtibial amputation is generally greater compared with able-bodied individuals. One aim of powered prostheses is to reduce metabolic deficits by replicating biological ankle function. Individuals with transtibial amputation can activate their residual limb muscles to volitionally control bionic ankle prostheses for walking; however, it is unknown how myoelectric control performs outside the laboratory.
View Article and Find Full Text PDFPLoS One
January 2025
Department of Cell Biology and Anatomy, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
Clarifying the inceptive pathophysiology of hypertensive heart disease helps to impede the disease progression. Through coarctation of the infrarenal abdominal aorta (AA), we induced hypertension in minipigs and evaluated physiological reactions and morpho-functional changes of the heart. Moderate aortic coarctation was achieved with approximately 30 mmHg systolic pressure gradient in minipigs.
View Article and Find Full Text PDFHeliyon
January 2025
Faculty of Sport Science, Ningbo University, Ningbo, 315211, China.
The long jump is an athletic event that demands speed, power, force application, and balance, with each phase being critical to overall performance. However, previous research has neglected the limiting effect of the wedge pedals on ankle dorsiflexion range of motion. This cross-sectional study investigated biomechanical changes in the lower extremities during long jumps under varying degrees of ankle dorsiflexion.
View Article and Find Full Text PDFJ Electromyogr Kinesiol
January 2025
Department of Human Health and Nutritional Sciences, University of Guelph, 50 Stone Road E, Guelph, ON N1G 2W1, Canada. Electronic address:
Rate of torque development (RTD) measures how rapidly one can generate torque and is crucial for balance and athletic performance. Fast RTD depends on the rapid recruitment of high threshold motor units (MUs). Cutaneous electrical stimulation has been shown to alter MU excitability, favoring high threshold MUs via reduced recruitment thresholds.
View Article and Find Full Text PDFBiophys J
January 2025
Department of Biological Sciences & Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute Troy, NY 12180, USA; Department of Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute Troy, NY 12180, USA. Electronic address:
Stretch activation (SA), a delayed increase in force production following rapid muscle lengthening, is critical to the function of vertebrate cardiac muscle and insect asynchronous indirect flight muscle (IFM). SA enables or increases power generation in muscle types used in a cyclical manner. Recently, myosin isoform expression has been implicated as a mechanism for varying the amplitude of SA in some muscle types.
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