Search results for "adaptation"
showing 10 items of 1775 documents
Voluntary activation and mechanical performance of human triceps surae muscle after exhaustive stretch-shortening cycle jumping exercise.
2003
The purpose of this study was to examine neuromuscular factors that may contribute to post exercise force loss and subsequent recovery after exhaustive stretch-shortening cycle (SSC) exercise. Six subjects were fatigued on a sledge apparatus by 100 maximal rebound jumps followed by continuous submaximal jumping until complete exhaustion. Exercise-induced changes in neuromuscular performance were followed up to 7 days post exercise. The total number of jumps in the SSC exercise ranged from 336 to 1392. The SSC exercise induced a significant immediate plantarflexion torque decline of 29, 38 and 44% (P<0.05) in maximal voluntary contraction and evoked maximal twitch and low-frequency (LF) stim…
Do low burnout and high work engagement always go hand in hand? Investigation of the energy and identification dimensions in longitudinal data
2011
The aim of the present 2-year follow-up study among young managers (N=433) was to investigate the intraindividual developmental patterns of burnout and work engagement as well as their interconnections. More specifically, we examined the interconnectedness of the varying patterns (i.e., latent classes) of exhaustion and vigor (i.e., the energy dimension) and cynicism and dedication (i.e., the identification dimension) across time. The latent class solutions supported by the growth mixture modeling indicated four latent classes for exhaustion and five for vigor. In addition, four latent classes were found for cynicism and six for dedication. Cynicism and dedication represented opposites with…
Association between vigor and exhaustion during the workweek: a person-centered approach to daily assessments.
2014
The purpose of this quantitative diary study was to investigate daily vigor and exhaustion using a person-centered approach. The study also investigated whether and how experiences of vigor and exhaustion relate to a state of being recovered. A total of 256 Finnish employees filled in a diary questionnaire during five consecutive workdays. Vigor and exhaustion showed strong negative interdependence within and between days. However, by applying a person-centered analysis, we were able to differentiate three groups with meaningful variation in vigor and exhaustion. The groups were labeled as Constantly vigorous (n = 179), Concurrently vigorous and exhausted (n = 30) and Constantly exhausted (…
Tracing patterns of activity in the human skeleton: an overview of methods, problems, and limits of interpretation.
2009
Studies of patterns of activity in human skeletal remains have grown in number over the last few years. Different methods have been used to reconstruct activity patterns in past populations. In this review of the available literature the common themes of these studies have been isolated in order to show that many studies do not truly conform to the standards of the field. Inadequate sample size, too far-reaching conclusions and neglect of other possible explanations are among the problems easily recognised in the literature. Many assumptions are lacking a sound experimental basis, and it becomes increasingly evident that there are many more problems and limits of interpretations than have b…
Methodological Aspects of the Application of the Naka-Rushton Equation to Clinical Electroretinogram
1993
The nonlinear relation between stimulus intensity and response amplitude of the electroretinogram (ERG) scotopic b wave can be described by a curve based on the Naka-Rushton (NR) equation. Up to now, the NR equation has been used to assess the features of the normal and pathological ERG, but the best approach for a correct evaluation of the parameters is still debatable. The parameters are thought to be related to the different conditions of retinal activities. The method is well known in experimental laboratories but is quite unusual at the clinical level. In the present paper the derivative analysis of the NR function is proposed as an easier approach to understand the variations of the N…
Oxidative stress in marathon runners: interest of antioxidant supplementation
2006
We have recently reported that xanthine oxidase is involved in the generation of free radicals in exhaustive exercise. Allopurinol, an inhibitor of xanthine oxidase, prevents it. The aim of the present work was to elucidate the role of exercise-derived reactive oxygen species in the cell signalling pathways involved in the adaptation to exercise in man. We have found that exercise causes an increase in the activity of plasma xanthine oxidase and an activation of NF-κB in peripheral blood lymphocytes after marathon running. This activation is dependent on free radical formation in exercise: treatment with allopurinol completely prevents it. In animal models, we previously showed that NF-κB a…
Improvement in altitude performance test after further acclimatization in pre-acclimatized soldiers.
2013
The Altitude Performance Test is a measure designed to assess an individual's degree of acclimatization to reduce the risk of acute mountain sickness during high-altitude activities. The aim of this study was to investigate the hypothesis that test results will improve in pre-acclimatized soldiers after several days of further acclimatization. The Altitude Performance Test consists of an uphill run at high altitude. The event is timed and performed with continuous oxygen saturation (SpO2) monitoring. The individual's time and lowest SpO2 measurement are recorded. This test was performed on the first day of arriving at 11,060 ft, and after 9 days at the same location. The 37 male soldiers we…
Prismatic Adaptation Modulates Oscillatory EEG Correlates of Motor Preparation but Not Visual Attention in Healthy Participants.
2017
Prismatic adaption (PA) has been proposed as a tool to induce neural plasticity and is used to help neglect rehabilitation. It leads to a recalibration of visuomotor coordination during pointing as well as to aftereffects on a number of sensorimotor and attention tasks, but whether these effects originate at a motor or attentional level remains a matter of debate. Our aim was to further characterize PA aftereffects by using an approach that allows distinguishing between effects on attentional and motor processes. We recorded EEG in healthy human participants (9 females and 7 males) while performing a new double step, anticipatory attention/motor preparation paradigm before and after adaptat…
Preattentive and attentive responses to changes in small numerosities of tones in adult humans
2016
The brain hosts a primitive number sense to non-symbolically represent numerosities of objects or events. Small exact numerosities (~4 or less) can be individuated in parallel. In contrast, large numerosities (more than ~4) can only be approximated. However, whether small numerosities can be approximated without their parallel individuation remains unclear. Parallel individuation is suggested to be an attentive process and numerical approximation an automatic process. We, therefore, tested whether small numerosities can be represented preattentively. We recorded adult humans׳ event-related potentials (ERPs) and behavioral responses to 300-ms sequences of six tones (each of either 440 Hz or …
Myocardial and peripheral vascular functional adaptation to exercise training.
2007
Exercise training seems to restore impaired vascular function in both peripheral and myocardial vessels in patients with coronary artery and peripheral vascular disease or in patients with risk factors for these diseases. However, the results on the effects of exercise training on vascular function in apparently healthy subjects are controversial. We studied the effects of long-term volitionally increased physical activity on peripheral and myocardial vascular function in nine young healthy male monozygotic twin pairs discordant for physical activity and fitness. The brothers were divided into more (MAG) and less active groups according to physical activity and fitness. The difference betwe…