Search results for " position"
showing 10 items of 548 documents
Variability in Lateral Positioning of Surface EMG Electrodes
2009
The positions of EMG electrodes over the knee extensor muscles were examined in 19 healthy men using MR images; electrodes were placed according to the SENIAM (surface electromyography for non-invasive assessment of muscles) guidelines. From axial images, the medial and lateral borders of the muscles were identified, and the arc length of the muscle surface was measured. The electrode location was expressed as a percentage value from the muscle’s medial border. EMGs were recorded during isometric maximal contraction, squat jumps, and countermovement jumps and analyzed for cross-correlation. The results showed that variations in lateral positioning were greatest in vastus medialis (47% SD 11…
Influence of Beach Chair Position on Cerebral Oxygen Saturation
2013
Although beach chair position (BCP) is frequently used for shoulder surgery, a potentially detrimental influence on cerebral oxygenation is discussed. Therefore, the present study investigated changes in regional cerebral oxygen saturation (rSO2/StO2) during BCP comparing 2 different devices for near-infrared spectroscopy measurement.Data were collected in 35 patients undergoing shoulder surgery in BCP and compared with a control group of 35 awake volunteers. The rSO2/StO2 was assessed using INVOS and FORE-SIGHT monitors. Mean arterial blood pressure (MAP), peripheral oxygen saturation (SpO2), PeCO2, FiO2, end-tidal sevoflurane concentration, and rSO2/StO2 were measured before positioning, …
Influence of St John's wort on catecholamine turnover and cardiovascular regulation in humans
2004
BACKGROUND: St John's wort (Hypericum perforatum) is a popular over-the-counter antidepressant. Its antidepressive effect has been attributed in part to inhibition of monoamine transporters and monoamine oxidase, on the basis of in vitro studies. METHODS: In a double-blind, randomized, placebo-controlled, crossover study, 16 healthy subjects (11 men and 5 women; mean age, 31 +/- 5 years) ingested either St John's wort (300 mg three times daily) or placebo for 7 days. Imipramine treatment (50 mg three times daily) in 7 subjects served as a positive control. After treatment, physiologic and biochemical tests included cardiovascular reflex testing, graded head-up tilt testing, and plasma catec…
Associations of parental education and parental physical activity (PA) with children's PA: The ENERGY cross‐sectional study
2012
OBJECTIVE The present study sought to examine the independent associations of parental education and physical activity (PA) with children's PA across Europe. METHODS A total of 7214 children (10-12 years) were recruited from a school-based cross-sectional survey during 2010 in seven European countries. Weight and height were measured. Parental educational level (PEL) and parents' and children's PA were collected using self-reported questionnaires. Multiple linear regression models were used, comparing children's PA with PEL and PA levels. RESULTS PEL was directly associated with children's PA in Greek and Spanish girls (all P < 0.01) and boys’ PA in Norway (all P < 0.05). Paternal education…
Intermediate nerve schwannoma: A rare tumour
2011
The intermediate nerve (IN), also called the nerve of Wrisberg, is a relatively small nerve with a variable anatomical course. Currently, this nerve is not addressed well in the pertinent literature. Pre-operative diagnosis of IN tumours is clinically challenging due to the lack of related symptoms. Symptoms are typically caused by the functional deterioration of neighbouring anatomical structures. In this report, we describe a patient with a schwannoma that arose at the porus acusticus of the internal auditory canal; during surgery, this proved to originate from the IN. We discuss our findings in the context of previously reported cases of IN schwannomas and analyse the vague characteristi…
Mechanisms of causal interaction between short-term RR interval and systolic arterial pressure oscillations during orthostatic challenge
2013
The transition from the supine to the upright position requires a reorganization of the mechanisms of cardiovascular control that, if not properly accomplished, may lead to neurally mediated syncope. We investigated how the patterns of causality between systolic arterial pressure (SAP) and cardiac RR interval were modified by prolonged head-up tilt using a novel nonlinear approach based on corrected conditional entropy (CCE) compared with the standard approach exploiting the cross-correlation function (CCF). Measures of coupling strength and delay of the causal interactions from SAP to RR and from RR to SAP were obtained in 10 patients with recurrent, neurally mediated syncope (RNMS) and 10…
Acute Physiological Responses to Four Running Sessions Performed at Different Intensity Zones
2020
AbstractThis study investigated acute responses and post 24-h recovery to four running sessions performed at different intensity zones by supine heart rate variability, countermovement jump, and a submaximal running test. A total of 24 recreationally endurance-trained male subjects performed 90 min low-intensity (LIT), 30 min moderate-intensity (MOD), 6×3 min high-intensity interval (HIIT) and 10×30 s supramaximal-intensity interval (SMIT) exercises on a treadmill. Heart rate variability decreased acutely after all sessions, and the decrease was greater after MOD compared to LIT and SMIT (p<0.001; p<0.01) and HIIT compared to LIT (p<0.01). Countermovement jump decreased only after …
Investigating centre of mass stabilisation as the goal of posture and movement coordination during human whole body reaching
2000
In the light of experimental results showing significant forward centre of mass (CoM) displacements within the base of support, this study investigated if whole body reaching movements can be executed whilst keeping the CoM fixed in the horizontal axis. Using kinematic simulation techniques, angular configurations were recreated from experimental data imposing two constraints: a constant horizontal position of the CoM and an identical trajectory of the hand to grasp an object. The comparison between recorded and simulated trials showed that stabilisation of the CoM was associated with greater backward hip displacements, which became more marked with increasing object distance. This was in c…
Pointing to double-step visual stimuli from a standing position: motor corrections when the speed-accuracy trade-off is unexpectedly modified in-flig…
2011
The time required to complete a fast and accurate movement is a function of its amplitude and the target size. This phenomenon refers to the well known speed-accuracy trade-off. Some interpretations have suggested that the speed-accuracy trade-off is already integrated into the movement planning phase. More specifically, pointing movements may be planned to minimize the variance of the final hand position. However, goal-directed movements can be altered at any time, if for instance, the target location is changed during execution. Thus, one possible limitation of these interpretations may be that they underestimate feedback processes. To further investigate this hypothesis we designed an ex…
The Effects of Hemianopia on Perception of Mutual Gaze
2019
Significance Individuals with left hemianopic field loss (HFL), especially with neglect history, may have greater difficulties than individuals with right HFL in judging the direction of another person's gaze. Purpose Individuals with HFL often show a spatial bias in laboratory-based perceptual tasks. We investigated whether such biases also manifest in a more real-world task, perception of mutual gaze direction, an important, nonverbal communication cue in social interactions. Methods Participants adjusted the eye position of a life-size virtual head on a monitor at a 1-m distance until (1) the eyes appeared to be looking straight at them, or (2) the eyes were perceived to be no longer loo…