Article
Physiology
Harry T. Swift, Jamie M. O'Driscoll, Damian D. Coleman, Anthony De Caux, Jonathan D. Wiles
Summary: This study found that isometric wall squat exercise involving larger muscle mass leads to a significantly greater reduction in blood pressure during a 10-minute recovery period compared to isometric handgrip exercise involving smaller muscle mass. The significantly greater reduction in total peripheral resistance may be an important mechanism for this difference in blood pressure response.
EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY
(2022)
Article
Neurosciences
Alessandro Del Vecchio, Carina Marconi Germer, Thomas M. Kinfe, Stefano Nuccio, Francois Hug, Bjoern Eskofier, Dario Farina, Roger M. Enoka
Summary: The purpose of this study was to identify the low-dimensional latent components, called motor unit modes, underlying the discharge rates of motor units in knee extensors and hand muscles during submaximal isometric contractions. Factor analysis identified two independent motor unit modes that captured most of the covariance of the motor unit discharge rates. The distribution of motor unit modes was different between hand and knee muscles, with a continuous distribution found for the knee muscles.
JOURNAL OF NEUROSCIENCE
(2023)
Article
Multidisciplinary Sciences
Laura Pellegrino, Martina Coscia, Psiche Giannoni, Lucio Marinelli, Maura Casadio
Summary: Stroke often impairs the control of the contralesional arm, but also affects the ability of the ipsilesional arm to produce well-controlled isometric forces, especially in pushing or pulling in lateral directions. This effect is mainly associated with abnormal activity of proximal muscles compared to matched controls.
SCIENTIFIC REPORTS
(2021)
Article
Sport Sciences
Ivana Petrovic, Ioannis G. Amiridis, Ales Holobar, Georgios Trypidakis, Chrysostomos Sahinis, Theodoros Kannas, Eleftherios Kellis, Roger M. Enoka
Summary: This study aimed to evaluate the effect of habitual training history on force steadiness and motor unit discharge characteristics in the tibialis anterior muscle during submaximal isometric contractions. The results showed that there were no significant differences in muscle force and force fluctuations between athletes with different training emphasis. Additionally, the discharge rate of motor units in the tibialis anterior muscle did not vary significantly at different levels of muscle force.
JOURNAL OF SPORTS SCIENCE AND MEDICINE
(2023)
Article
Sport Sciences
Ivana Petrovic, Ioannis G. Amiridis, Ales Holobar, Georgios Trypidakis, Chrysostomos Sahinis, Theodoros Kannas, Eleftherios Kellis, Roger M. Enoka
Summary: The aim of this study was to assess the influence of habitual training history on force steadiness and the discharge characteristics of motor units. The results showed that athletes who trained with either alternating actions or bilateral actions had similar effects on maximal force, force control, and variability in synaptic input during a single-limb isometric task.
JOURNAL OF SPORTS SCIENCE AND MEDICINE
(2023)
Article
Sport Sciences
Ivana Petrovic, Ioannis G. Amiridis, Ales Holobar, Georgios Trypidakis, Eleftherios Kellis, Roger M. Enoka
Summary: The aim of this study was to compare the maximal force, force steadiness, and discharge characteristics of motor units in the tibialis anterior muscle during contractions with the dorsiflexors of the dominant and nondominant legs at different ankle angles and target forces. The results showed that the maximal force and force steadiness were similar between the two legs, regardless of the ankle angle or target force. The attributes associated with the dominant leg were not related to the force capacity or control of the dorsiflexor muscles.
MEDICINE & SCIENCE IN SPORTS & EXERCISE
(2022)
Article
Chemistry, Analytical
Philipp Bauer, Joao Sa Gomes, Joao Oliveira, Paulo Santos, Pedro Pezarat-Correia, Joao R. Vaz
Summary: The present study aimed to investigate the effects of a continuous visual feedback and the isometric contraction nature on the complexity and variability of force. Results showed that the push isometric task with visual feedback (P-visual) had higher complexity and decreased variability compared to the other tasks. There were no significant differences between the hold isometric task without visual feedback (Hnon-visual) and the hold isometric task with visual feedback (H-visual). These findings suggested that different motor control strategies were induced by the two isometric tasks, and the influence of visual feedback depended on the type of isometric task.
Article
Chemistry, Multidisciplinary
Ziga Kozinc, Jernej Plesa, Daniel Djuric, Nejc Sarabon
Summary: The study found that ballistic contractions have higher rate of force development (RFD) in later time intervals compared to explosive sustained contractions, with larger differences in females. Peak RFD was also higher in ballistic contractions, suggesting their use for primary RFD assessment.
APPLIED SCIENCES-BASEL
(2022)
Article
Multidisciplinary Sciences
Dorian Glories, Mathias Soulhol, David Amarantini, Julien Duclay
Summary: The study compared modulations of corticomuscular coherence (CMC) and changes in spinal excitability during different muscle contraction types, finding that CMC was significantly lower during lengthening contractions, indicating a potential involvement of spinal regulatory mechanisms in beta-band CMC modulation.
SCIENTIFIC REPORTS
(2021)
Article
Engineering, Biomedical
Robin Rohlen, Marco Carbonaro, Giacinto L. Cerone, Kristen M. Meiburger, Alberto Botter, Christer Gronlund
Summary: This study examined the repeatability of ultrasound images in distinguishing muscle motor units (MUs) from noise in low-force isometric contractions. It was found that the repeatable components accounted for about one-third of the MUs and can be used for data reduction.
JOURNAL OF NEURAL ENGINEERING
(2023)
Article
Physics, Applied
Dixiao Chen, Ziping Yang, Yiming Ji, Yuguo Dai, Lin Feng, Fumihito Arai
Summary: The magnetically actuated robot shows great potential in the field of microoperation due to its excellent motion characteristics, high motion accuracy, and high measured output force. The study focuses on developing a ferrofluid-based robot for transporting tiny particles and blocks in confined spaces.
APPLIED PHYSICS LETTERS
(2021)
Article
Sport Sciences
Eirini Tsatsaki, Ioannis G. Amiridis, Ales Holobar, Georgios Trypidakis, Fotini Arabatzi, Eleftherios Kellis, Roger M. Enoka
Summary: The study aimed to evaluate the impact of muscle length on dorsiflexor force steadiness and motor unit discharge characteristics during submaximal contractions. Results showed that muscle length affected force steadiness and the average discharge rate of motor units varied at different ankle angles.
EUROPEAN JOURNAL OF SPORT SCIENCE
(2022)
Article
Physiology
Eduardo Martinez-Valdes, Francesco Negro, Alberto Botter, Patricio A. Pincheira, Giacinto Luigi Cerone, Deborah Falla, Glen A. Lichtwark, Andrew G. Cresswell
Summary: The integration of electromyography (EMG) and ultrasound imaging has provided important insights into muscle activation and contraction mechanisms. This study demonstrates the relationship between tibialis anterior muscle (TA) motor unit discharge, fascicle length, and dorsiflexion torque using ultrasound-transparent high-density EMG electrodes. The findings highlight the interplay between neural drive, muscle contraction, and torque during sustained isometric contractions.
JOURNAL OF APPLIED PHYSIOLOGY
(2022)
Article
Physiology
Andrea Casolo, Alessandro Del Vecchio, Thomas G. Balshaw, Sumiaki Maeo, Marcel Bahia Lanza, Francesco Felici, Jonathan P. Folland, Dario Farina
Summary: The study found that the recruitment strategies and discharge characteristics of motor units in the biceps brachii of strength-trained athletes were similar to those in untrained individuals during submaximal force tasks. It was also observed that strength-trained athletes are able to produce greater absolute muscle forces for the same neural input, indicating that morphological factors play a predominant role in enhanced force generation during submaximal efforts.
JOURNAL OF APPLIED PHYSIOLOGY
(2021)
Article
Nutrition & Dietetics
J. Greig Inglis, David A. Gabriel
Summary: This study found that females exhibit lower force steadiness and higher coefficient of variation of motor unit action potential inter-pulse interval compared to males at submaximal and maximal force outputs. This may be due to differences in motor unit behaviors leading to the observed differences in force steadiness between the sexes.
APPLIED PHYSIOLOGY NUTRITION AND METABOLISM
(2021)