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Biomedical subjects

P Ekkekakis

Publications and source records attributed to P Ekkekakis.

7 recordsLinked to original sources
PubMed2006

Exercise does not feel the same when you are overweight: the impact of self-selected and imposed intensity on affect and exertion.

OBJECTIVE: The lower rates of adherence to physical activity commonly found among overweight adults compared to their normal-weight counterparts might be due to the activity being experienced as more laborious and less pleasant, particularly when its intensity is prescribed (or imposed) rather than self-selected. DESIGN: Within-subject design, with two 20-min sessions of treadmill exercise, one at self-selected speed and one at imposed speed, 10% higher than the self-selected. SUBJECTS: A total of 16 overweight (BMI: 31 kg/m2) and 9 normal-weight (BMI: 22 kg/m2) previously sedentary but healthy women (age: 43 years). MEASUREMENTS: Heart rate, oxygen uptake relative to body weight, and ratings of perceived exertion and pleasure-displeasure were assessed every 5 min. RESULTS: The overweight women showed higher oxygen uptake and perceived exertion than the normal-weight women during both sessions. Although the two groups did not differ in ratings of pleasure-displeasure during the session at self-selected speed, only the overweight women showed a significant decline when the speed was imposed. CONCLUSIONS: Imposing a speed that is just 10% higher than what overweight women would have self-selected led to a significant decline in reported pleasure. Over time, this could diminish the enjoyment of and intrinsic motivation for physical activity, reducing adherence.

Adult↗
PubMed2005

The exercise-induced enhancement of influenza immunity is mediated in part by improvements in psychosocial factors in older adults.

The primary goal of this study was to determine whether exercise-associated improvements of the immune response to influenza vaccination were mediated by improvements in psychosocial factors in older adults. At baseline, prior to the exercise intervention, older adult participants were immunized with influenza vaccine. Blood samples collected pre-immunization, 1, 4, and 12 weeks post-immunization were analyzed for anti-influenza antibody, whereas influenza-specific cytokine (IFNgamma) was evaluated at 1 week post-immunization. Depression and sense of coherence were measured pre-immunization. Four weeks post-immunization, participants were randomly assigned to either an aerobic exercise group (n=14) or a control group (n=14). After a 10-month exercise intervention, the immunization, blood collections, and psychosocial measures were repeated. At the post-intervention evaluation, exercise participants had improved scores on depression and sense of coherence. Also post-intervention, exercise participants had a greater increase in antibody and IFNgamma production. After controlling for the effect of both psychosocial measures, the exercise treatment remained significant with respect to antibody titer suggesting that the increases in antibody were not mediated by improvement in the psychosocial factors. In contrast, the enhancement of IFNgamma appeared to be mediated at least in part by the psychosocial factors. After controlling for psychosocial factors, exercise treatment was no longer significantly related to the change in IFNgamma. Taken together, our findings may suggest that the mechanism(s) of exercise-induced improvement in immunocompetence involve both physiological and psychological pathways.

Affect↗
PubMed2001

Regional brain activation as a biological marker of affective responsivity to acute exercise: influence of fitness.

Previous research has shown that regional brain activation, assessed via frontal electroencephalographic (EEG) asymmetry, predicts affective responsivity to aerobic exercise. To replicate and extend this work, in the present study we examined whether resting brain activation was associated with affective responses to an acute bout of aerobic exercise and the extent to which aerobic fitness mediated this relationship. Participants (high-fit, n = 22; low/moderate-fit, n = 45) ran on a treadmill for 30 min at 75% VO2max. EEG and affect were assessed pre- and 0-, 10-, 20-, and 30-min postexercise. Resting EEG asymmetry predicted positive affect (as measured by the energetic arousal subscale of the Activation Deactivation Adjective Check List) postexercise. Furthermore, resting frontal EEG asymmetry predicted affect only in the high-fit group, suggesting the effect might be mediated by some factor related to fitness. It was also shown that subjects with relatively greater left frontal activation had significantly more energy (i.e., activated pleasant affect) following exercise than subjects with relatively greater right frontal activation. In conclusion, aerobic fitness influenced the relationship between resting frontal asymmetry and exercise-related affective responsivity.

Adult↗
PubMed2000

Walking in (affective) circles: can short walks enhance affect?

Recent physical activity recommendations call for activities that are of moderate intensity and can be performed intermittently during the day, such as walking. These proclamations were based partly on the assumption that moderate activities are generally more enjoyable than physically demanding ones, and they are, therefore, also more likely to be continued over the long haul. However, little is actually known about the affective outcomes of short bouts of walking and extant findings are equivocal. Four experimental studies examined the affective responses associated with short (10- to 15-min) bouts of walking using a dimensional conceptual model of affect, namely, the circumplex. Results consistently showed that walking was associated with shifts toward increased activation and more positive affective valence. Recovery from walking for 10-15 min was associated with a return toward calmness and relaxation. This pattern, was robust across different self-report measures of the circumplex affective dimensions, across ecological settings (field and laboratory), across time, and across samples.

Adult↗
PubMed1999

Acute aerobic exercise and affect: current status, problems and prospects regarding dose-response.

One of the assumptions underlying recent physical activity recommendations is that lower doses of activity (i.e. intensity and duration) are more enjoyable for the average person, thus leading to higher involvement and adherence rates. However, the veracity of this hypothesis can be questioned, since little is actually known regarding the association between activity doses and affective responses. The few preliminary attempts at the conceptual delineation of the dose-response relationship, all centred around an 'inverted-U' notion, are reviewed and criticised as lacking empirical foundation. Available meta-analyses, as well as the empirical literature on the role of exercise intensity and duration, are examined. Increased intensity appears to be associated with reduced positivity of affect during and immediately following an exercise bout. Intensity effects appear to be attenuated during recovery. Fitness and training status appear to become significant mediators of the exercise-affect relationship only at high intensities. With intensity being kept constant, different exercise bout durations have not been shown to have a differential impact on pre- to post-exercise affective changes. Recommendations for future research include: (i) a shift from categorical to dimensional conceptualisations and operationalisations of affect; (ii) the examination of psychological theories on the association between activation and affect (e.g. extraversion-introversion, sensation seeking, type A behaviour pattern and related self-evaluative tendencies, reversal theory, optimal stimulation theory, multidimensional activation theory and self-efficacy); (iii) the systematic and theory-based examination of in-task and post-exercise affective responses; (iv) the incorporation of the parameter of fitness and/or activity status in research designs; and (v) the re-evaluation of methods for selecting exercise intensity levels.

Emotions↗
PubMed1999

A Web-based digitized video image system for the study of motor coordination.

A Web-based instructional project for the study of motor coordination is presented. The project includes two components: a tutorial on motor coordination and an interactive digitized video image system developed for the analysis of motion, including topics in biomechanics, motor coordination, motor control, and motor skill. This interactive system allows for the quantitative analysis of stored video images that are accessible from the World-Wide Web. The use of this digitizing system for the measurement and analysis of human locomotion coordination patterns is presented.

Computer-Assisted Instruction↗