Search results for "Task"
showing 10 items of 1658 documents
Developing motor planning over ages
2009
International audience; Few studies have explored the development of response selection processes in children in the case of object manipulation. In the current research, we studied the end-state comfort effect, the tendency to ensure a comfortable position at the end rather than at the beginning of simple object manipulation tasks. We used two versions of the unimanual bar transport task. In Experiment 1, only 10-year-olds reached the same level of sensitivity to end-state comfort as adults, and 8-year-olds were less efficient than 6-year-olds. In each age group, children’s sensitivity did not increase during a session: i.e., either clearly showed the sensitivity or showed no sensitivity a…
Daily modulation of the speed–accuracy trade-off
2017
International audience; Goal-oriented arm movements are characterized by a balance between speed and accuracy. The relation between speed and accuracy has been formalized by Fitts’ law and predicts a linear increase in movement duration with task constraints. Up to now this relation has been investigated on a short-time scale only, that is during a single experimental session, although chronobiological studies report that the motor system is shaped by circadian rhythms. Here, we examine whether the speed–accuracy trade-off could vary during the day. Healthy adults carried out arm-pointing movements as accurately and fast as possible toward targets of different sizes at various hours of the …
Context-dependent neuroelectric responses during motor control
2015
Abstract Research on brain responses during motor control is usually performed under typical laboratory settings. However, everyday life and the laboratory differ in many aspects, such as purposeful and motivated behavior; and there's no awareness of “being measured” in everyday life. In the laboratory, movements are usually explicitly instructed, overtly measured and follow no intrinsic motivated purpose. Therefore, here we present a new method to measure and reliably analyze neuroelectric brain responses by EEG, as well as kinematics during the performance of grasping movements in two different behavioral contexts. One context (L) simulates a typical laboratory task and another context (E…
Analyzing gastrocnemius EMG-activity and sway data from quiet and perturbed standing.
2007
In an experiment, we combined force plate measurements and surface EMG in studying quiet and perturbed standing, involving MS (Multiple sclerosis) and controls. The aim of this paper is to report the results thus obtained on the relation between filtered gastrocnemius (GA) EMG and the anterior-posterior center-of-pressure (A/P COP) coordinate. The main finding is the good correspondence between A/P COP and the filtered GA EMG in the low frequency range. The EMG envelope was calculated using a zero-lag filter. Combining this with time shifts around 250-350 ms produced a high correlation (85.5+/-8.4%) between the GA-EMG envelope and the A/P COP. This EMG-COP relation was closest when using a …
Intensified job demands and job performance: does SOC strategy use make a difference?
2019
We examined intensified job demands (IJDs) and selecting-optimizing-compensating (SOC) strategies as predictors of job performance (task performance, organizational citizenship behavior). We also investigated SOC strategy use as a moderator in the linkages between IJDs and performance. We sampled three disparate occupational groups (N=4,582). We found that certain dimensions of IJDs showed significant associations with the indicators of job performance but there were also scale-based variations in these linkages, depending on the type of performance and on the sub-scale of IJDs. Specifically, some dimensions of IJDs (e.g., work intensification) related to poorer task performance whereas som…
Physical and psychosocial prerequisites of functioning in relation to work ability and general subjective well-being among office workers
2002
Objectives The purpose of the study was to investigate the physical and psychological prerequisites of functioning, as well as the social environment at work and personal factors, in relation to work ability and general subjective well-being in a group of office workers. Methods The study was a descriptive cross-sectional investigation, using path analysis, of office workers. The subjects comprised 88 volunteers, 24 men and 64 women, from the same workplace [mean age 45.7 (SD 8.6) years]. The independent variables were measured using psychosocial and physical questionnaires and physical measurements. The first dependent variable, work ability, was measured by a work ability index. The secon…
The Use of Testosterone/Cortisol Ratio in Response to Acute Stress as an Indicator of Propensity to Anger in Informal Caregivers
2016
AbstractCaring for an offspring diagnosed with a psychological chronic disorder is used in research as a model of chronic stress. Indeed, it is usually associated with disturbances in the salivary cortisol (Csal) levels of the caregiver. An imbalance between salivary testosterone (Tsal) and Csal levels is a marker of proneness to social aggression. Given this, we aimed to establish whether the salivary testosterone/cortisol (Tsal/Csal) ratio response to acute stress could be employed as a marker of proneness to anger in informal caregivers of offspring with autism spectrum (ASD). Tsal/Csal ratio and anger responses to a set of different cognitive tasks as well as anger trait and expression …
Comparison of the 45-Second/15-Second Intermittent Running Field Test and the Continuous Treadmill Test
2012
Purposes:To compare the physiological responses and maximal aerobic running velocity (MAV) during an incremental intermittent (45-s run/15-s rest) field test (45-15FIT) vs an incremental continuous treadmill test (TR) and to demonstrate that the MAV obtained during 45-15FIT (MAV45-15) was relevant to elicit a high percentage of maximal oxygen uptake (VO2max) during a 30-s/30-s intermittent training session.Methods:Oxygen uptake (VO2), heart rate (HR), and lactate concentration ([La]) were measured in 20 subjects during 2 maximal incremental tests and four 15-min intermittent tests. The time spent above 90% and 95% VO2max (t90% and t95% VO2max, respectively) was determined.Results:Maximal ph…
Measuring Task-Switching Ability in the Implicit Association Test
2005
Abstract. Recently, the role of method-specific variance in the Implicit Association Test (IAT) was examined ( McFarland & Crouch, 2002 ; Mierke & Klauer, 2003 ). This article presents a new content-unspecific control task for the assessment of task-switching ability within the IAT methodology. Study 1 showed that this task exhibited good internal consistency and stability. Studies 2-4 examined method-specific variance in the IAT and showed that the control task is significantly associated with conventionally scored IAT effects of the IAT-Anxiety. Using the D measures proposed by Greenwald, Nosek, and Banaji (2003 ), the amount of method-specific variance in the IAT-Anxiety could b…
Effects of whole-body vertical shock-type vibration on human ability for fine manual control
1991
The effects of vertical (z-axis) whole-body shock-type vibration on the ability for fine manual control were examined. The amplitudes and frequency of the shocks was varied, but a constant frequency-weighted acceleration of 1.25 m/s2 r.m.s. was maintained. The examination of the shock's effects was carried out using an experimental system that simulated the actual workplace of earth-moving machinery. Control was measured using a first-order pursuit tracking-test, in which a seated subject was asked to use both hands to direct a cursor on a monitor using a steering wheel. Although the magnitude of shocks (peak amplitude of 6-10 m/s2) and the number of shocks per unit time (shock cycle of 10-…