Search results for "KINEMATICS"
showing 10 items of 481 documents
Modulation of premotor mirror neuron activity during observation of unpredictable grasping movements.
2004
Using transcranial magnetic stimulation, we explored the properties of premotor mirror neurons during the passive observation of a reaching-grasping movement in human subjects. Two different experiments were run using video-clips as visual stimuli. Video-clips showed a normally performed (control stimulus) or an anomalous reaching-grasping movement executed by delaying the time of the appearance of the maximal finger aperture (experiment 1), or substituting it with an unpredictable closure (experiment 2). Motor evoked potentials were recorded at different time-points during the observation of the video-clips. Profiles of cortical excitability were drawn and compared with the kinematic profi…
Kinematic features of movement tunes perception and action coupling
2005
How do we extrapolate the final position of hand trajectory that suddenly vanishes behind a wall? Studies showing maintenance of cortical activity after objects in motion disappear suggest that internal model of action may be recalled to reconstruct the missing part of the trajectory. Although supported by neurophysiological and brain imaging studies, behavioural evidence for this hypothesis is sparse. Further, in humans, it is unknown if the recall of internal model of action at motion observation can be tuned with kinematic features of movement. Here, we propose a novel experiment to address this question. Each stimulus consisted of a dot moving either upwards or downwards, and correspond…
Motion analysis in the field of dentistry: a kinematic comparison of dentists and orthodontists
2016
Objectives: To conduct a kinematic comparison of occupational posture in orthodontists and dentists in their workplace. Design: Observational study. Setting: Dentist surgeries and departments of orthodontics at university medical centres in Germany. Participants: A representative sample of 21 (10 female, 11 male) dentists (group G1) and 21 (13 female, 8 male) orthodontists (G2) with one male dropout in G2. Outcome measures: The CUELA (computer-assisted acquisition and long-term analysis of musculoskeletal loads) system was used to analyse occupational posture. Parallel to the recording through the CUELA system, a software-supported analysis of the activities performed (I: treatment; II: off…
Biomechanical factors affecting running economy.
2001
KYROLAINEN, H., A. BELLI, and P. V. KOMI. Biomechanical factors affecting running economy. Med. Sci. Sports Exerc., Vol. 33, No. 8, 2001, pp. 1330 -1337. Purpose: The present study was designed to investigate kinematics, kinetics, and muscle activity for explaining running economy at different running speeds. Methods: A total of 17 young endurance runners ran at 12-13 different running speeds. Respiratory gases were collected. Kinematic records were obtained by a high-speed video camera, and 3-D ground reaction forces (GRF) were measured simultaneously with telemetric EMG recordings of the selected leg muscles. In the analysis, joint moments and power were calculated by inverse dynamic meth…
A hierarchical cluster analysis to determine whether injured runners exhibit similar kinematic gait patterns
2020
Previous studies have suggested that runners can be subgrouped based on homogeneous gait patterns, however, no previous study has assessed the presence of such subgroups in a population of individuals across a wide variety of injuries. Therefore, the purpose of this study was to assess whether distinct subgroups with homogeneous running patterns can be identified among a large group of injured and healthy runners and whether identified subgroups are associated with specific injury location. Three‐dimensional kinematic data from 291 injured and healthy runners, representing both sexes and a wide range of ages (10‐66 years) was clustered using hierarchical cluster analysis. Cluster analysis r…
Comparison of running kinematics between elite and national-standard 1500-m runners.
2009
The aim of this study was to determine whether elite 1500-m runners differ in their running kinematics from national-standard 1500-m runners. Six national-standard male runners (seasonal best: 3 min 49.2 s +/- 3.2 s) were assessed during the second lap of a 1500-m race. Their running kinematics was then compared with those of five elite runners (seasonal best: 3 min 35.6 s +/- 2.6 s) analysed during the second lap of the men's 1500-m final at the 2005 World Championships. Data were collected using two high-speed cameras operating at 200 Hz with a three-dimensional pan and tilt system. Running speed was the same for both groups. Despite the similar contact times, the minimum knee angle durin…
Achilles tendon stiffness is unchanged one hour after a marathon
2012
Overuse-induced injuries have been proposed as a predisposing factor for Achilles tendon (AT) ruptures. If tendons can be overloaded, their mechanical properties should change during exercise. Because there data are lacking on the effects of a single bout of long-lasting exercise on AT mechanical properties, the present study measured AT stiffness before and after a marathon. AT stiffness was determined as the slope of the force–elongation curve between 10 and 80% of maximum voluntary force. AT force–elongation characteristics were measured in an ankle dynamometer using simultaneous motion-capture-assisted ultrasonography. Oxygen consumption and ankle kinematics were also measured on a trea…
Kinematic analysis of motor strategies in frail aged adults during the Timed Up and Go: how to spot the motor frailty?
2015
Asma Hassani,1 Alexandre Kubicki,2,3 Vincent Brost,1 France Mourey,2,4 Fan Yang1 1Laboratoire LE2I CNRS 6306, Université de Bourgogne, Dijon, France; 2Institut National de la Santé et de la Recherche Médicale (INSERM), Cognition Action et Plasticité Sensori-Motrice, Campus Universitaire, Université de Bourgogne, Dijon, France; 3Centre Hospitalier Universitaire de Dijon, Hôpital de Champmaillot, Dijon, France; 4Faculté de Médecine, Université de Bourgogne, Dijon, France Objective: The purpose of this work was to analyze and compare the movement kinematics of sit-to-stand (STS) and back-to-sit (B…
Mechanical step variability during treadmill running.
1995
The present study was designed to study intra-individual step variability measured both on vertical displacement of the body (delta Z) and on step time (delta t) parameters by means of a kinematic arm and during treadmill running. A group of 17 subjects ran successively at 60%, 80%, 100% and 140% of their maximal aerobic velocity (Vamax). The total number of steps analysed was 6116. The absolute delta Z step variability (sigma delta Z) ranged between 5 mm and 21 mm while the absolute delta t variability (sigma delta t) ranged between 6 ms and 40 ms. Step variabilities were due to step asymmetry (from 38.5% to 48.5% of the step variability) and to stride variability. For submaximal velocitie…
Electromyographic and kinematic analysis of therapeutic knee exercises under water.
2001
Abstract Objective. This study aimed to evaluate muscle function and kinematics during commonly used knee rehabilitation exercises performed in water. Design. Maximal effort single extension and flexion trials in still water and repeated extension–flexion trials in flowing water in barefoot condition were analysed from 18 healthy participants (8 men, 10 women). Background. Despite the fact that water exercises are widely used, there are only few studies involving biomechanical and hydrodynamical analysis of aquatic exercises in rehabilitation. Methods. Electromyography of the quadriceps (vastus medialis, vastus lateralis) and hamstring muscles (biceps femoris, semitendinosus) and angular ve…