Search results for "analysis of variance"
showing 10 items of 1183 documents
Effect of body composition on the neuromuscular function of Finnish conscripts during an 8-week basic training period.
2008
The dropout rate in the Finnish military service has increased during the past two decades. At the same time, the physical fitness level of young Finnish males has decreased, possibly leading to overtraining in new conscripts. The purpose of the present study was to examine whether body composition would influence neuromuscular function during the 8-week basic training (BT) period. Eighteen healthy male subjects (19 +/- 1 years) were divided into three different groups according to their body fat %. Group 1 (10%), group 2 (10-13%) and group 3 (13%). The soleus H-reflex response was measured in the standing position. In the seated position (knee 160 degrees and hip 110 degrees), the V-wave r…
Postural Control Mechanisms in Healthy Adults in Sitting and Standing Positions
2015
This study explored differences in the center of pressure in healthy people in a sitting and standing position and with eyes open and closed. With this purpose, 32 healthy participants (16 men, 16 women; M age = 25.2 yr., SD = 10.0, range = 18–55) were measured with an extensiometric force plate. Using a two–way repeated-measures multivariate analysis of variance (MANOVA), the root mean square, velocity, range, and sway, in both visual conditions, had higher values in the standing task than in the sitting task. In the frequency domain, the low-frequency band had higher values during the standing task. For control mechanism variables, mean distance and time were greater when standing while …
Measurement invariance, validation and normative data of the Jenkins Sleep Scale-4 (JSS-4) in the German general population across the life span.
2019
Abstract Objective As sleep disorders have become a major concern in public health, there is strong need for a brief and sound measure for sleep problems. The purposes of the study were to 1) evaluate factor structure and measurement invariance, 2) validate the scale based on sociodemographic data and distress, and 3) provide norm values for the general population. Methods In a representative survey of the German population N = 2515 participants (14 to 95 years) filled in the 4-item Jenkins Sleep Scale (JSS-4), sociodemographic questions and the Brief Symptom Inventory-18 (anxiety, depression, somatic symptom load). The JSS-4 was analyzed by principal component analysis, confirmatory and mu…
Auditory Mismatch Negativity and Repetition Suppression Deficits in Schizophrenia Explained by Irregular Computation of Prediction Error
2015
Background The predictive coding model is rapidly gaining attention in schizophrenia research. It posits the neuronal computation of residual variance (‘prediction error’) between sensory information and top-down expectation through multiple hierarchical levels. Event-related potentials (ERP) reflect cortical processing stages that are increasingly interpreted in the light of the predictive coding hypothesis. Both mismatch negativity (MMN) and repetition suppression (RS) measures are considered a prediction error correlates based on error detection and error minimization, respectively. Methods Twenty-five schizophrenia patients and 25 healthy controls completed auditory tasks designed to el…
Global and regional cortical thinning in first-episode psychosis patients: relationships with clinical and cognitive features
2010
BackgroundThe thickness of the cortical mantle is a sensitive measure for identifying alterations in cortical structure. We aimed to explore whether first episode schizophrenia patients already show a significant cortical thinning and whether cortical thickness anomalies may significantly influence clinical and cognitive features.MethodWe investigated regional changes in cortical thickness in a large and heterogeneous sample of schizophrenia spectrum patients (n=142) at their first break of the illness and healthy controls (n=83). Magnetic resonance imaging brain scans (1.5 T) were obtained and images were analyzed by using brains2. The contribution of sociodemographic, cognitive and clinic…
Alliesthesia in visual and auditory sensations from environmental signals.
2007
'Alliesthesia' describes the fact that sensory stimuli can arouse pleasant or unpleasant sensations according to the internal state of a person. In the present work, the hedonicity aroused by stimuli from the environment in visual and auditory sensations was evaluated in 5 situations: 1) daytime without sensory stimulations (no video-tape); 2) daytime with poor sensory stimulations (uninteresting video-tape film); 3) daytime with rich sensory stimulations (interesting chosen movie on video-tape); 4) night-time without sensory stimulations (no video-tape); 5) night-time with poor sensory stimulations (uninteresting video-tape). During the day, hedonic ratings decreased with time in the no- a…
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…
Lower limb muscle weakness predicts use of a multiple- versus single-step strategy to recover from forward loss of balance in older adults.
2012
BACKGROUND: Older adults compared with young adults have reduced strength and balance recovery ability. The purpose of the present study was to investigate whether age, sex, and/or lower limb strength predicted the stepping strategy used to recover from a forward loss of balance. METHODS: Ninety-five, community-dwelling, older adults, aged 65-90 years, participated in the study. Loss of balance was induced by releasing participants from a static forward lean. Participants performed four trials at three initial lean magnitudes and were subsequently classified as using a single- or multiple-step strategy. Isometric strength of the ankle, knee, and hip joint flexors and extensors was assessed …
Decline in motor prediction in elderly subjects: right versus left arm differences in mentally simulated motor actions.
2008
This study investigates the effects of age upon the temporal features of executed and imagined movements performed with the dominant (D; right) and nondominant (ND; left) arms. Thirty right-handed subjects were divided into two groups: (i) the young group (n=15; mean age: 22.5+/-2.5 years) and (ii) the elderly group (n=15; mean age: 70.2+/-2.2 years). The motor task, involving arm pointing movements among four pairs of targets (.5cm, 1cm, 1.5cm and 2cm), imposed strong spatiotemporal constraints. During overt performance, young and elderly subjects modulated movement duration according to the size of targets, despite the fact that movement speed decreased with age as well as in the left arm…
Mentally represented motor actions in normal aging: III. Electromyographic features of imagined arm movements.
2009
Abstract Motor imagery is a cognitive process during which subjects mentally simulate movements without actually performing them. Here, we investigated the temporal and electromyographic (EMG) features of imagined arm movements in healthy elderly adults. Twelve young (mean age: 24.0 ± 1.3 years) and 12 elderly (mean age: 67.0 ± 4.5 years) participants executed and mentally simulated, with their right and left arms and as fast and as accurately as possible, arm pointing movements between three targets located in the frontal plane. We used the mental chronometry paradigm as an indicator of the accuracy of the motor imagery process (i.e. isochrony between executed and imagined movements) and t…