Search results for "Muscular force"
showing 8 items of 8 documents
The effects of course length on freestyle swimming speed in elite female and male swimmers - a comparison of swimmers at national and international l…
2013
Abstract Freestyle swimming performance over 50 m, 100 m, 200 m, 400 m, 800 m and 1,500 m was compared on short (25 m) and long (50 m) course for 92,196 national swimmers (i.e. annual high score list Switzerland) and 1,104 international swimmers (i.e. finalists FINA World Championships) from 2000 to 2012. National and international swimmers of both sexes were on average 2.0 ± 0.6% faster on short than on long course. Sex-related differences in swimming speed were greater on short than on long course for international and national swimmers from 50 m to 800 m. Freestyle swimming performance improved across years for international swimmers in both short- and long-course whereas only male natio…
Effect of innervation zones in estimating biceps brachii force-EMG relationship during isometric contraction
2012
Measuring muscle forces in vivo is invasive and consequently indirect methods e.g., electromyography (EMG) are used in estimating muscular force production. The aim of the present paper was to examine what kind of effect the disruption of the physiological signal caused by the innervation zone has in predicting the force/torque output from surface EMG. Twelve men (age 26 (SD ±3)years; height 179 (±6)cm; body mass 73 (±6)kg) volunteered as subjects. They were asked to perform maximal voluntary isometric contraction (MVC) in elbow flexion, and submaximal contractions at 10%, 20%, 30%, 40%, 50% and 75% of the recorded MVC. EMG was measured from biceps brachii muscle with an electrode grid of 5…
Cycling exercise and the determination of electromechanical delay.
2007
The main aim of the present paper was to address the validity of a methodology proposed in a previous paper [Li L, Baum BS. Electromechanical delay estimated by using electromyography during cycling at different pedaling frequencies. J Electromyogr Kinesiol 2004;14(6):647-52], aimed at determining the electromechanical delay from pedaling exercise performed at various cadences. Twelve trained subjects undertook pedaling bouts corresponding to combinations of cadences ranging from 50 to 100 RPM and power output from 37.5% to 75% of Pmax. As cadence increased, peak torque angle was found to shift forward in crank cycle (from 60-65 degrees at 50 RPM to 75-80 degrees at 100 RPM, depending on th…
Matlab-based interface for the simultaneous acquisition of force measures and Doppler ultrasound muscular images
2012
This paper tackles the design of a graphical user interface (GUI) based on Matlab (MathWorks Inc., MA), a worldwide standard in the processing of biosignals, which allows the acquisition of muscular force signals and images from a ultrasound scanner simultaneously. Thus, it is possible to unify two key magnitudes for analyzing the evolution of muscular injuries: the force exerted by the muscle and section/length of the muscle when such force is exerted. This paper describes the modules developed to finally show its applicability with a case study to analyze the functioning capacity of the shoulder rotator cuff.
Controlling muscular force by functional electrical stimulation using intelligent PID
2015
Functional Electrical Stimulation (FES) appears as a way of extremely promising research today to solve numerous pathology connected to the deficiencies of the nervous system. It is usually used for the rehabilitation of people with neurological disorders. Generally, skeletal muscles are activated by using Constant Frequency Trains (CFTs) with a fixed amplitude and inter-pulse duration. In addition, the systems of electrical stimulation do not adapt the parameters stimulation to obtain a desired force response during the rehabilitation session. The purpose of this study is to adapt automatically the stimulation parameters to the force desired by the clinician with an intelligent PID control…
Model Free Control for muscular force by Functional Electrical Stimulation using pulse width modulation
2016
International audience; Functional Electrical Stimulation (FES) is a useful technique for restoring functions for patients with neurological disorders. Muscle activities can be artificially driven through delivery of electrical pulses to skeletal muscles. Typically, muscles are activated by using constant stimulation train with a fixed parameters (amplitude, frequency and pulse width). In addition, the FES systems do not adapt the parameters stimulation to obtain a desired force response during the rehabilitation session. The purpose of this study is to investigate a real-time FES system for adapting automatically the stimulation parameters (stimulation pulse width) to track a desired force…
Adaptations neuromusculaires des muscles extenseurs du genou : contractions fatigantes uni- vs bi-latérales
2010
The aim of this work was to determine i) the influence of the level of absolute force on the duration of the endurance time, and subsequent neuromuscular alterations in same individual at the end of an exercise performed at the same relative intensity, with one or two legs, ii) the influence of central drive on the force capacity production of the knee extensor muscles during unilateral (UL) vs. bilateral (BL) contractions, iii) activation mechanisms evolution for a serie of submaximal evoked contractions by electrostimulation (EMS). The results of the first study confirm that the endurance limit depends on the level of absolute force for the same individual, contraction duration for UL is …
On the control of a muscular force model including muscular fatigue
2015
Electromyostimulation has been used for several decades by athletes or physiotherapists in order to create a muscular reinforcement. However, the efficiency of electromyostimulation is limited by muscular fatigue and by induced pain. Currently, the systems of electromyostimulation do not adapt the stimulation parameters automatically by taking into account physiological parameters such as muscular fatigue. To adapt the stimulation parameters to muscular responses and in order to optimize the rehabilitation sessions, a control of force using an indicator of muscular fatigue could be used. In this paper, we propose two ways to control the force by using a physiological model which includes th…