Search results for "Muscle Contraction"

Ultrasound imaging assessment of the diaphragm and abdominal muscles in people with a recent history of moderate Covid-19 infection and healthy parti…

2023

Coronavirus disease (Covid-19) is a highly infectious disease caused by the SARS-CoV-2 virus and is associated with a decrease of respiratory, physical, and psychological function, subsequently affecting quality of life. The aim of the present pilot study was to use ultrasound imaging (USI) to evaluate and compare the thickness of the diaphragm and abdominal muscles between individuals recently diagnosed with moderate Covid-19 infection and healthy individuals. Methods: A cross-sectional observational pilot study was performed. A total sample of 24 participants were recruited from a private medical center (Madrid, Spain): Covid-19 (n = 12) and healthy controls (n = 12). The external oblique…

2015

The execution of unilateral hand contractions before performance has been reported to produce behavioral aftereffects in various tasks. These effects have been regularly attributed to an induced shift in activation asymmetry to the contralateral hemisphere produced by the contractions. An alternative explanation proposes a generalized state of reduced bilateral cortical activity following unilateral hand contractions. The current experiment contrasted the above explanation models and tested the state of cortical activity after the termination of unilateral hand contractions. Twenty right-handed participants performed hand contractions in two blocks, one for each hand. Using electroencephalo…

Effects of moderate vs. high iso-inertial loads on power, velocity, work and hamstring contractile function after flywheel resistance exercise.

2019

Flywheel iso-inertial training has been shown to positively affect muscular strength and sports performance (e.g. agility). However, implementing such eccentrically-biased training during a microcycle needs to be carefully planned due to its purported effects on the neuromuscular system that can last for hours/days post-exercise. This study aimed at using tensiomyography to verify the effects of different inertias during the hip extension exercise on the contractile function of biceps femoris and semitendinosus muscles of the dominant leg for up to 72 hours post-exercise. Thirty participants (24.4 ± 3.4 years) were divided into 0.075 or 0.1 kg·m2 inertia groups and a control group. Magnitud…

Effect of radiofrequency and pelvic floor muscle training in the treatment of women with vaginal laxity: A study protocol

2021

Background Vaginal laxity is an underreported condition that negatively affects women’s sexual function and their relationships. Evidence-based studies are needed to better understand this complaint and to discuss its treatment options. Thus, we present a study protocol to compare the effect of radiofrequency and pelvic floor muscle training in the treatment of women with complaints of vaginal laxity. Methods/Design This is a prospective, parallel-group, two-arm, randomized clinical trial (Registry: RBR-2zdvfp–REBEC). Participants will be randomly assigned to one of the two groups of intervention (Radiofrequency or Pelvic Floor Muscle Training). The study will be performed in the Urogyneco…

Slower Walking Speed in Older Men Improves Triceps Surae Force Generation Ability

2016

Purpose \ud Older adults walk slower than young adults, but it is not known why. Previous research suggests that ankle plantarflexors may have a crucial role in the reduction of walking speed. The purpose of this study was to investigate age-related differences in triceps surae muscle–tendon function during walking to further investigate the role of plantarflexors in the age-related reduction of walking speed.\ud \ud Methods \ud Medial gastrocnemius and soleus muscle fascicle lengths were measured using ultrasound imaging during walking from 13 young (25 ± 4 yr) men at preferred walking speed and from 13 older (73 ± 5 yr) men at preferred speed and at the young men’s preferred speed. Muscle…

Comparison of force-velocity relationships of vastus lateralis muscle in isokinetic and in stretch-shortening cycle exercises

2003

Aim:  This study investigated the force–velocity characteristics of the vastus lateralis (VL) muscle fascicle and muscle–tendon unit (MTU) in isolated lengthening and shortening actions, and during natural movement. Methods:  Four subjects performed maximal eccentric and concentric knee extensions (60, 120 and 180° s−1). Unilateral counter movement jumps and drop jumps in the sledge apparatus served as natural movements. Vastus lateralis fascicle lengths were determined from ultrasonography. In vivo patellar tendon forces (PTF) were measured with an optic fibre technique. Patellar tendon force was derived to VL force according to the cross-sectional area of the muscle. Force in the directio…

Muscle fascicle and tendon behavior during human locomotion revisited.

2008

High-speed ultrasonography has revealed that, in human locomotion, the nature of fascicle and tendon length changes varies depending on the task, contraction intensity, and the muscles involved. The findings emphasize that the active fascicles of the gastrocnemius muscle are suddenly stretched, although they are shortening. This short-lasting stretch triggers the stretch reflex, timing of which is dependent on running speed.

Relaxant effects of flavonoids on the mouse isolated stomach: structure-activity relationships.

2008

Flavonoids are a large heterogeneous group of benzo-gamma-pyrone derivatives, which are abundantly present in our diet. In this study we investigated the effects of six flavonoids (apigenin, genistein, quercetin, rutin, naringenin and catechin) on the gastric tone in mouse isolated stomach. The mechanical activity was recorded as changes of intraluminal pressure. All flavonoids tested produced a concentration-dependent relaxation, which was reversible after washout. The relative order of potency of the flavonoids was apigenin> or =genistein>quercetin>naringenin> or =rutin>catechin. Analysis of the chemical structure showed that the relaxant activity was progressively diminished by the prese…

The avian oesophageal motor function and its nervous control: some physiological, pharmacological and comparative aspects.

1991

1. This paper deals with the avian oesophageal motor function and it attempts to draw some comparative aspects between neural regulation of the avian and mammalian oesophagus. 2. Different from the mammalian oesophagus, the avian oesophagus, presents at rest electrical activity associated to spontaneous contractions. 3. Swallowing elicits peristaltic contraction, characterized by an inhibitory and an excitatory component. 4. Non-adrenergic, non-cholinergic neurons are responsible for the inhibitory component. 5. Contrarily to what observed in mammals, where the peripheral mechanism are important for the peristaltic sequence, the primary peristaltism of birds seems to be entirely mediated by…

Coordination and Integration of Metabolism in Insect Flight*

1997

Abstract Insect flight is the most energy-demanding activity of animals. It requires the coordination and cooperation of many tissues, with the nervous system and neurohormones controlling the performance and energy metabolism of muscles, and of the fat body, ensuring that the muscles and nerves are supplied with essential fuels throughout flight. Muscle metabolism can be based on several different fuels, the proportions of which vary according to the insect species and the stage in flight activity. Octopamine, which acts as neurotransmitter, neuromodulator or neurohormone in insects, has a central role in flight. It is present in brain, ventral ganglia and nerves, supplying peripheral tiss…