Search results for "force"
showing 10 items of 3423 documents
Neuromuscular control in landing from supra-maximal dropping height.
2009
International audience; The present study utilized high-impact supra-maximal landings to examine the influence of the pre-impact force level on the post-impact electromyographic (EMG) activity and, in particular, on the short latency EMG reflex (SLR) component. Unilateral-leg landings were performed in a sitting position on a sledge apparatus after release from high, but individually constant dropping height. A lower limb guiding device fixed to the front of the sledge seat allowed the subjects to sustain a given pre-set force level up to impact. This force level was either freely chosen or set at 20, 35, and 50% of maximal isometric plantarflexion force. EMG activity was recorded from eigh…
Heart rate variability related to effort at work
2011
Changes in autonomic nervous system function have been related to work stress induced increases in cardiovascular morbidity and mortality. Our purpose was to examine whether various heart rate variability (HRV) measures and new HRV-based relaxation measures are related to self-reported chronic work stress and daily emotions. The relaxation measures are based on neural network modelling of individual baseline heart rate and HRV information. Nineteen healthy hospital workers were studied during two work days during the same work period. Daytime, work time and night time heart rate, as well as physical activity were recorded. An effort-reward imbalance (ERI) questionnaire was used to assess ch…
The impact of mastication, salivation and food bolus formation on salt release during bread consumption
2014
Health authorities recommend higher fibre and lower salt content in bread products. However, these basic ingredients of bread composition are multifunctional, and important changes in their content influence the texture, flavour and acceptability of the product. This study was designed to investigate the link between oral processing, bolus formation and sodium release during the consumption of four different breads that varied in composition and structure. Chewing behaviour was determined by surface electromyography, and salivation was quantified from the water content of the boluses collected. The kinetics of bread degradation during food bolus formation was characterised by measuring the …
Diagnosing fatigue in gait patterns by support vector machines and self-organizing maps
2009
The aim of the study was to train and test support vector machines (SVM) and self-organizing maps (SOM) to correctly classify gait patterns before, during and after complete leg exhaustion by isokinetic leg exercises. Ground reaction forces were derived for 18 gait cycles on 9 adult participants. Immediately before the trials 7-12, participants were required to completely exhaust their calves with the aid of additional weights (44.4±8.8kg). Data were analyzed using: (a) the time courses directly and (b) only the deviations from each individual's calculated average gait pattern. On an inter-individual level the person recognition of the gait patterns was 100% realizable. Fatigue recognition …
Force-, EMG-, and elasticity-velocity relationships at submaximal, maximal and supramaximal running speeds in sprinters.
1986
The relationships between ground reaction forces, electromyographic activity (EMG), elasticity and running velocity were investigated at five speeds from submaximal to supramaximal levels in 11 male and 8 female sprinters. Supramaximal running was performed by a towing system. Reaction forces were measured on a force platform. EMGs were recorded telemetrically with surface electrodes from the vastus lateralis and gastrocnemius muscles, and elasticity of the contact leg was evaluated with spring constant values measured by film analysis. Data showed increases in most of the parameters studied with increasing running speed. At supramaximal velocity (10.36 +/- 0.31 m X s-1; 108.4 +/- 3.8%) the…
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…
Motor planning of arm movements is direction-dependent in the gravity field.
2007
International audience; In the present study we analyzed kinematic and dynamic features of arm movements in order to better elucidate how the motor system integrates environmental constraints (gravity) into motor planning and control processes. To reach this aim, we experimentally manipulated the mechanical effects of gravity on the arm while maintaining arm inertia constant (i.e. the distribution of the mass around the shoulder joint). Six subjects performed single-joint arm movements (rotation around the shoulder joint) in both sagittal (upward, U, versus downward, D) and horizontal (left, L, versus right, R) planes, at different amplitudes and from different initial positions. Under thes…
Country and gender differences in the motivation of dental students - An international comparison
2018
PURPOSE The objective of this study, conducted in Germany, Finland and Turkey, was to identify whether motivations to study dentistry varied by country, gender or year of study. METHODS The multicentre pilot study was conducted in English language in 2014. Participants (n = 469 dental students) were either in the first or last year of study. The response rate was 91%. RESULTS The sample comprised 63% females and 37% males, reflecting the common gender distribution in dental education. A total of 236 first year students (50.3%) and 233 final year students (49.7%) took part in the study. The participants were aged 21-25 years and of 15 different nationalities, mostly from Turkey, Germany and …
Expiratory airflow obstruction due to tracheostomy tube: A spirometric study in 50 patients
2018
OBJECTIVES Tracheostomy is commonly used in intensive care units and in head and neck departments. Airway obstruction due to occluded cuffless tracheostomy tubes themselves remains unknown, although capping trials are commonly used before decannulation. The aim of this study was to evaluate the extent to which airway obstruction can be caused by occluded cuffless tubes in patients who underwent head and neck surgery. DESIGN Prospective Research Outcome. SETTINGS University teaching hospital. PARTICIPANTS Fifty patients requiring transient tracheostomy after head and neck surgery. MAIN OUTCOME MEASURES A flow-volume loop (FVL) through the mouth using a portable spirometer, with the occluded …
Longitudinal analysis of endurance and respiratory function from a natural history study of Morquio A syndrome
2015
Objectives: Baseline data from the Morquio A Clinical Assessment Program (MorCAP) revealed that individuals with Morquio A syndrome show substantial impairment in multiple domains including endurance and respiratory function (Harmatz et al., Mol Genet Metab, 2013). Here, 1- and 2-year longitudinal endurance and respiratory function data are presented.Methods: Endurance was assessed using the 6-minute walk test (6MWT) and the 3-minute stair climb test (3MSCT). Respiratory function was evaluated by measuring forced vital capacity (PVC) and maximum voluntary ventilation (MW). Data were analyzed using repeated measures ANCOVA models. Annualized estimates of change were determined using model es…