The reported anabolic action of some beta 2 agonists may have clinical applications in certain muscle wasting states. Administration of clenbuterol (2 mg/kg diet for 14 days) to rats resulted in a limited degree of hypertrophy of normal muscles; the effect was more pronounced on fast-twitch muscles than on slow-twitch muscles. The anabolic effect was greatest in denervated muscles, where it was significantly more effective on the slow-twitch type. Clenbuterol significantly improved the contractile properties of denervated slow-twitch muscle, reverting them toward normal, but had little effect on contractile properties of denervated fast-twitch muscle. Such differential effects of clenbuterol must be taken into consideration in the evaluation of any future human intervention study.
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http://dx.doi.org/10.1002/mus.880130305 | DOI Listing |
Wearable Technol
February 2025
Neuromuscular Robotics Laboratory, Department of Biomechanical Engineering, University of Twente, Enschede, the Netherlands.
Research in lower limb wearable robotic control has largely focused on reducing the metabolic cost of walking or compensating for a portion of the biological joint torque, for example, by applying support proportional to estimated biological joint torques. However, due to different musculotendon unit (MTU) contractile speed properties, less attention has been given to the development of wearable robotic controllers that can steer MTU dynamics directly. Therefore, closed-loop control of MTU dynamics needs to be robust across fiber phenotypes, that is ranging from slow type I to fast type IIx in humans.
View Article and Find Full Text PDFNat Cell Biol
March 2025
Department of Cell and Tissue Dynamics, Max Planck Institute for Molecular Biomedicine, Münster, Germany.
Tissue deformations are a central feature of development, from early embryogenesis, growth and building the body plan to the establishment of functional organs. These deformations often result from active contractile forces generated by cells and cell collectives, and are mediated by changes in their mechanical properties. Mechanical forces drive the formation of functional organ architectures, but they also coordinate cell behaviour and fate transitions, ensuring robustness of development.
View Article and Find Full Text PDFSci Rep
March 2025
Laboratory of Exercise Physiology, Department of Movement, Human, and Health Sciences, University of Rome "Foro Italico", Rome, Italy.
Neural determinants explaining the asymmetrical force and skill observed in limb dominance still need to be comprehensively investigated. To address this gap, we recorded myoelectrical activity from biceps brachii using high-density surface electromyography in twenty participants, identifying the maximal voluntary force (MVF) and performing isometric ramp contractions at 35% and 70%MVF and sustained contractions at 10%MVF. Motor unit discharge characteristics were assessed during ramp contractions, the proportion of common synaptic input to motoneurons was calculated with coherence analysis, and the firing rate hysteresis (∆F) was used to estimate spinal motoneuron intrinsic properties.
View Article and Find Full Text PDFPLoS One
March 2025
Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America.
Skeletal muscle architecture is a key determinant of muscle function. Architectural properties such as fascicle length, pennation angle, and curvature can be characterized using Diffusion Tensor Imaging (DTI), but acquiring these data during a contraction is not currently feasible. However, an image registration-based strategy may be able to convert muscle architectural properties observed at rest to their contracted state.
View Article and Find Full Text PDFWorld J Cardiol
February 2025
Department of Pharmaceutical Technology, "Victor Babes" University of Medicine and Pharmacy, Timisoara 300041, Romania.
Background: Cardiovascular diseases are the first cause of death in the world. Ischemic heart disease is the main cause of heart failure. New approaches are continuously sought to identify better therapeutic success.
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