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At least 433 records · Page 24Linked to original sources
PubMed1976

Changes in muscle fibre size and physical performance in patients with rheumatoid arthritis after 7 months physical training.

Ten patients with rheumatoid arthritis of moderate severity were given 7 months' physical training. During the investigation period the patiens improved their physical performance capacity as well as they lowered their rate of perceived exertion during submaximum exercise. There was a small increase in muscle fibre size and a correlation was found between muscle strength and type II fibre size. Clinical examination and X-ray studies did not reveal any further joint destruction during the investigation period.

Adult↗
PubMed2002

Physics in cell biology: on the physics of biopolymers and molecular motors.

"What is Life?" is the title of a book by Erwin Schrödinger, first published in 1944. This book is a bold attempt to try to understand some of the wonders of life in terms of physics, in particular statistical mechanics. Since the publication of this visionary book, we have seen a revolution in molecular biology complemented by the development of new physical tools like single-molecule spectroscopy. The goal of this article is to highlight some examples where physics can contribute to questions in cell biology. One might hope that through interdisciplinary research one can get closer to answering Schrödinger's fundamental question.

Biophysical Phenomena↗
PubMed1979

Physical model evaluation of topical prodrug delivery-simultaneous transport and bioconversion of vidarabine-5'-valerate I: Physical model development.

A physical model approach to the topical delivery of a vidarabine ester prodrug was investigated. It involved modeling, theoretical simulations, experimental method development for factoring and quantifying parameters, and, finally, employment of the deduced parameters to determine the steady-state species fluxes and concentration profiles in the target tissue. The present report describes the physical modeling and theoretical simulation aspects. The physical model for the simultaneous transport and bioconversion of a topically delivered prodrug was formulated assuming homogeneous enzyme distributions and constant diffusivities in the membrane. The mathematical problem was solved, and the solution yielded concentration profiles and fluxes of all species in the biomembrane. These results provided the prevailing levels of the prodrug, the drug, and the metabolite at the target site and the transport rates of all species into the bloodstream. Computations of concentration profiles and fluxes were carried out for a reasonable range of the parameters. The relative activities of the esterase and the deaminase enzymes, as well as the stratum corneum permeabilities, were important in influencing the concentration profiles and fluxes of all species.

Administration, Topical↗
PubMed2006

Modeling individual and physical environmental factors with adolescent physical activity.

BACKGROUND: Recent calls have been made to consider both environmental factors and individual-level factors in the explanation of physical activity (PA). The present study tested a conceptual model that integrated past PA, relevant environmental-level and individual-level factors and their associations with adolescent PA, using the tenets of the Theory of Planned Behavior (TPB). METHODS: Data were gathered in an adolescent sample (n=221; 60% girls) using questionnaires. PA was assessed in May 2003 and November 2003. Theory of Planned Behavior cognitions regarding PA and the environmental factors under study were assessed in November 2003. Confirmatory factor analyses and path analyses were performed using AMOS software. RESULTS: The initial structural model did not provide an acceptable fit to the data. Including a direct path from past PA to current PA significantly improved model fit to an acceptable fit. Including a direct path from past PA to environmental perceptions did not significantly improve model fit. Including a direct path from the environmental variables to current PA did not significantly improve model fit. Current PA was most strongly influenced by past PA, while environmental aesthetics and distance to PA opportunities were indirectly related to adolescents' intention to be physically active. Significant standardized path coefficients ranged from 0.14 to 0.34 and explained 17% variance in current PA. CONCLUSIONS: Combining past PA, Theory of Planned Behavior cognitions, and environmental factors increased our understanding of their relative influences on adolescent PA. Implications for future research on physical activity are discussed.

Adolescent↗
PubMed2006

Effectiveness of physical counterpressure maneuvers in preventing vasovagal syncope: the Physical Counterpressure Manoeuvres Trial (PC-Trial).

OBJECTIVES: In this study, we assessed the effectiveness of physical counterpressure maneuvers (PCM) in daily life. BACKGROUND: There is presently no evidence-based therapy for vasovagal syncope. Current treatment consists of explanation and life-style advice. Physical counterpressure maneuvers have been shown to raise blood pressure and to control or abort vasovagal episodes in laboratory conditions. METHODS: We performed a multicenter, prospective, randomized clinical trial, which included 223 patients age 38.6 (+/-15.4) years with recurrent vasovagal syncope and recognizable prodromal symptoms. One hundred and seventeen patients were randomized to standardized conventional therapy alone, and 106 patients received conventional therapy plus training in PCM. RESULTS: The median yearly syncope burden during follow-up was significantly lower in the group trained in PCM than in the control group (p = 0.004). During a mean follow-up period of 14 months, overall 50.9% of the patients with conventional treatment and 31.6% of the patients trained in PCM experienced a syncopal recurrence (p = 0.005). Actuarial recurrence-free survival was better in the treatment group (log-rank p = 0.018), resulting in a relative risk reduction of 39% (95% confidence interval, 11% to 53%). No adverse events were reported. CONCLUSIONS: Physical counterpressure maneuvers are a risk-free, effective, and low-cost treatment method in patients with vasovagal syncope and recognizable prodromal symptoms, and should be advised as first-line treatment in patients presenting with vasovagal syncope with prodromal symptoms. (The PC-Trial; http://www.controlled-trials.com/isrctn/trial/45146526/0/45146526.html; ISRCTN45146526).

Actuarial Analysis↗
PubMed1998

The versatile nature of physical activity--on the psychological, behavioural and contextual characteristics of health-related physical activity.

This paper presents a comprehensive characterisation of physical activity based on psychological, behavioural and contextual aspects. Based on the characterisation it suggests a promotional classification of physical activity into five categories. The categories are: 1, Occupational activity; 2, Lifestyle activity; 3, Recreation activity; 4, Fitness activity; and 5, Sport activity. Examples are given of activities in each category and of the related emotional aspects, outcome expectations, degree of personal choice and health benefits. The importance of the emotional component and the relevance of the outcome expectations are discussed and contextual considerations are presented on the basis of the promotional classification. The implications of the classification for the practice of health-enhancing physical activity promotion are discussed.

Adult↗
PubMed1998

How can physical activity be changed--basic concepts and general principles in the promotion of health-related physical activity.

Basic concepts and general principles in the promotion of health-related physical activity are presented based on selected behavioral science theories, research findings and conceptual analysis. The concepts and principles selected include (1) a realistic and flexible concept of physical activity, (2) a pragmatic use of the determinants of physical activity, (3) targeting promotion to specific stages of adoption at a time, (4) a systematic facilitation of the change process by health communications and environmental changes, and (5) a stepwise organization of the promotional activities while respecting the target people's freedom of choice.

Adaptation, Psychological↗
PubMed2000

Physical activity and self-reported, physician-diagnosed osteoarthritis: is physical activity a risk factor?

This prospective study evaluated regular physical activity and self-reported physician-diagnosed osteoarthritis of the knee and/or hip joints among 16,961 people, ages 20-87, examined at the Cooper Clinic between 1970 and 1995. Among those aged 50 years and older, osteoarthritis incidence was higher among women (7.0 per 1000 person-years) than among men (4.9 per 1000 person-years, P = 0.001), while among those under 50 years of age, osteoarthritis incidence was similar between men (2.6) and women (2.7). High levels of physical activity (running 20 or more miles per week) were associated with osteoarthritis among men under age 50 after controlling for body mass index, smoking, and use of alcohol or caffeine (hazard ratio = 2.4, 95% CI: 1.5, 3.9), while no relationship was suggested among women or older men. These findings support the conclusion that high levels of physical activity may be a risk factor for symptomatic osteoarthritis among men under age 50.

Adult↗
PubMed1997

A four-year comparison of physical health benefit expenditures of mental and physical health claimants.

The pattern of covered physical health benefit expenditures before and after initiation of mental health treatment for a cohort of individuals with mild to moderate mental health problems was examined in this study. The results indicated the mental health treatment group (MHTG) began to have higher total covered benefits expenditures about one year prior to starting mental health treatment. Statistically significant differences between the MHTG and comparison groups (groups with no mental health treatments during the study period and matched on age and gender) began at the quarter just before treatment and continued through the seventh quarter after treatment initiation. The higher pattern of total health benefit expenditures of the MHTG declined gradually for two years before it returned to pretreatment levels. The study suggests the need for a better understanding of the types of physical health benefits expenditures preceding and following mental health treatment. It further indicates that the integration of physical and mental health benefits case management may have potential for reducing overall health benefit costs.

Adult↗
PubMed1998

Drug addiction as a physical disease: the role of physical dependence and other chronic drug-induced neurophysiological changes in compulsive drug self-administration.

Physical-dependence-based theories of addiction regard compulsive drug taking as the behavioral manifestation of a desperate need to relieve aversive autonomic withdrawal symptoms. In the present article, the withdrawal-relief paradigm, or opiate model of addiction, is critically examined in the light of recent experimental and clinical evidence for various addictive drugs. It is concluded that contrary to the opiate model, the constellation of pathological behaviors defining addiction (compulsive drug use, craving, loss of control, and a persistent tendency to relapse) does not primarily reflect a need to relieve actual or conditioned autonomic withdrawal symptoms. Recent theories of addiction emphasize the positive reinforcing properties of drugs and sensitization of brain dopamine systems rather than negative reinforcement or drug-opposing neuroadaptations. Despite the failure of the opiate model, recent evidence suggests that persistent drug-induced changes in the physical brain may underlie addictive behavior, consistent with the general notion of addiction as a physical disease.

Animals↗
PubMed2003

Spatial knowledge of a real school environment acquired from virtual or physical models by able-bodied children and children with physical disabilities.

In Experiment 1, 2 groups of able-bodied children were exposed to both a complex single-tier virtual environment (VE) and a physical model of a different environment. For 1 group, the VE accurately modeled a real school, and for the other group the physical model did so. In transfer testing in the real school, orientation accuracy was greater in the group exposed to the VE of the real school. In Experiment 2, children with physical disabilities explored the VE model of the real school and were tested as in the 1st experiment. Measures of orientation accuracy and map-placing were significantly better in this group than in the guessing adult control group. The results illustrate the potential for VEs as useful spatial training media.

Adolescent↗
PubMed2003

Physical activity in confined conditions as an indicator of free-living physical activity.

OBJECTIVE: The main determinants of daily energy expenditure are body size and physical activity. Activity energy expenditure is the most variable component of total energy expenditure. It was assessed whether the physical activity level in confined conditions is an indicator of free-living physical activity. RESEARCH METHODS AND PROCEDURES: Activity energy expenditure was measured over 1 day in a confined environment of a respiration chamber (floor space, 7.0 m(2)), where activities were restricted to low-intensity activities of daily living, and over 2 weeks in a free-living environment using doubly labeled water. Subjects were 16 women and 29 men (age, 31 +/- 10 years; BMI, 24.2 +/- 2.7 kg/m(2)). RESULTS: The free-living activity level of the subjects, as a multiple of resting energy expenditure, was 1.76 +/- 0.13. Activity energy expenditure in the chamber was 47 +/- 13% of the value in daily life, and the two values were correlated (r = 0.50, p < 0.001; partial correlation corrected for age, gender, and BMI: 0.40, p < 0.01). The chamber value explained 25% of the total variance in free-living activity energy expenditure. DISCUSSION: The activity level of a subject under sedentary conditions is an indicator of activity energy expenditure in daily life, showing the importance of nonexercise activity for daily energy expenditure.

Activities of Daily Living↗
PubMed1997

Assessment of Physics Quality Assurance in United States Radiotherapy Facilities and Comparison With American College of Radiology Standard for Radiation Oncology Physics for External Beam Therapy.

We have assessed radiation therapy physics quality assurance (QA) elements in the United States and compared the results with the Patterns of Care Study (PCS) Consensus Guidelines for Treatment Planning and the American College of Radiology (ACR) Standard for Radiation Oncology Physics for External Beam Therapy. Data were obtained during PCS site visits to 73 facilities randomly selected from the 1,321 radiation therapy facilities in the United States: 21 academic, 26 hospital, and 26 freestanding. The following is a representative sample of results. The estimated national averages for facilities having QA programs for treatment planning systems, simulators, accelerators, film processors, and blocking systems are 44%, 79%, 94%, 62%, and 55%, respectively. Only 63% of facilities obtain an independent check of their accelerator calibrations from a source outside the facilities obtain an independent check of their accelerator calibrations from a source outside the facility. Twenty-six percent of facilities surveyed did not have in vivo dosimetry capability. These results and others in the study were compared with PCS consensus guidelines and ACR standards, This is the first such study performed in the United States, and the results establish a baseline for future studies. A recommendation for a comprehensive national physics QA study is based on deficiencies found in this study and the implementation of new technologies in radiation therapy.

Journal Article↗
PubMed2003

Physical activity monitoring in Europe. The European Physical Activity Surveillance System (EUPASS) approach and indicator testing.

OBJECTIVES: The main objective of this paper is to describe the approach and specific findings of the European Physical Activity Surveillance System (EUPASS) research project. In particular, the analysis presented aims at testing the reliability, comparability and predictive power of different sets of physical activity (PA) indicators. DESIGN: First, a panel study based on computer-aided telephone interview (CATI) was designed to report PA data of a representative, selected group of about 100 persons per country at three points in time. Second, a CATI time series survey was carried out with the goal of realising about 100 interviews per month over six consecutive months. SETTING: The project was carried out in eight European countries to support the development of the European Union's (EU) Health Monitoring Programme. SUBJECTS: Random population samples (subjects aged 18 years and older) were drawn from each participating country. RESULTS: While many PA indicators used in EU countries to date as well as the psychosocial and environmental measures tested in the present study had acceptable to good reliability coefficients, the test-retest reliability scores of the International Physical Activity Questionnaire (IPAQ) version tested (the short (last 7 days) telephone interview IPAQ; IPAQ-S7T) were rather low. The comparability between extant national PA items and the IPAQ-S7T was low for all countries. The strongest predictors of perceived health were the psychosocial and environmental PA indicators. CONCLUSIONS: According to the results of the present study, more research is needed to further investigate and improve the quality of the IPAQ. In addition, the specific predictive power of the tested psychosocial and environmental PA indicators on perceived health should be of particular interest for designing health surveillance activities in the future.

Adolescent↗
PubMed2003

Using different physical activity measurements in eight European countries. Results of the European Physical Activity Surveillance System (EUPASS) time series survey.

OBJECTIVES: The European Physical Activity Surveillance System (EUPASS) research project compared several physical activity (PA) measures (including the International Physical Activity Questionnaire (IPAQ)) in a time series survey in eight countries of the European Union. The present paper describes first results provided by the different instruments regarding PA participation, frequency and duration, both at the European and national levels. The purpose of the present study is to explore and compare the specific quality and usefulness of different indicators rather than to provide valid and reliable prevalence data. Thus, the main focus is on discussion of the methodological implications of the results presented. METHODS: A time series survey based on computer-aided telephone interviewing (CATI) was carried out in eight European countries over a six-month period. The study provided for about 100 realised interviews per month in each country (i.e. approximately 600 per country). Descriptive statistical analysis was used to: (1) report IPAQ results on vigorous, moderate and light PA and sitting, as well as on the overall measure of calories expenditure (MET min-1), in the different countries; (2) compare these results with national PA indicators tested in EUPASS; and (3) compare IPAQ results with other European studies. RESULTS: First, the scores for the different PA categories as well as for the overall measure of calories expenditure provided by the IPAQ appeared rather high compared with previous studies and public health recommendations. Second, the different PA measurements used in EUPASS provided completely different results. For example, national indicators used in Germany and The Netherlands to date neither corresponded in absolute values (e.g. means of PA or sitting) nor correlated with the IPAQ in any significant way. Third, comparing EU countries, the ranking for vigorous, moderate and light activities by use of the IPAQ differed from that of other European studies. For example, in the present analysis, German respondents generally showed higher scores for PA than the Finns and the Dutch, while, in contrast, findings from other studies ranked Finland before The Netherlands and Germany. CONCLUSIONS: The present analysis highlights some methodological implications of the IPAQ instrument. Among other things, differences in overall scores for PA as well as in the ranking of nations between the present results using IPAQ and other measures and studies may partly be due to the concepts of PA behind the measurements. Further analysis should investigate if the range of PA-related categories provided by the IPAQ is fully appropriate to measure all relevant daily activities; it may also consider the public health implications of mixing up different contexts of PA (e.g. work, leisure-time, transportation) in the IPAQ short version.

Adult↗
PubMed2005

A pilot study of a web-based physical activity motivational program for adults with physical disabilities.

PURPOSE: Develop, deliver, and assess the efficacy of a 4-week web-based leisure-time physical activity (LTPA) motivational program based on the Transtheoretical Model and tailored to inactive adults with physical disabilities. METHOD: This was a pilot-based study incorporating a true experimental design with one treatment and one control group. The intervention program was delivered on the web and was based on the constructs of the Transtheoretical Model. From the 151 individuals who completed the LTPA standardized questionnaire at baseline, 75 people participated in the 1-month post-test assessment. RESULTS: The results of the analysis confirmed the pretest LTPA scores as the study covariate for the post-test assessment (F (1,72)=16.06, p=0.001, (2 )= 0.18). Based on the one-way ANCOVA, there were no statistically significant differences in LTPA scores between the treatment and control groups at post-test. However, the corresponding effect size and variance explained by the treatment approached a moderate level of significance (d=0.34 and (2 )= 0.04). CONCLUSIONS: Although conclusive statements about program effectiveness cannot be secured, several 'lessons learned' from this project may be 'key factors' for program improvement. Given the pilot nature of the study and the limited resources for program development and monitoring, continued examination of such motivational materials and delivery mechanisms for people with physical disabilities appear warranted.

Analysis of Variance↗
PubMed1998

Customary physical activity and physical health outcomes in later life.

OBJECTIVES: to explore associations between customary physical activity and three longitudinal outcomes: 12-year all-cause mortality, 12-year disease-specific mortality and 8-year change in general practitioner and personal social service use. DESIGN: longitudinal study. SUBJECTS: 1042 people originally aged 65 and over randomly sampled from general practitioner lists in Nottingham, UK. METHODS: Cox regression survival and logistic regression analyses. MAIN OUTCOME MEASURES: questionnaire-assessed levels of physical activity; 12-year mortality; reported health and personal social service contacts in month prior to interview. RESULTS: on the basis of factor scores derived from the interview questionnaire, activity levels were graded as high, intermediate or low, with respondents grouped accordingly. Relative to the high activity group, 12-year mortality was significantly increased in both the intermediate [adjusted hazard ratio (HR) = 1.53; 95% confidence interval (CI) = 1.10-2.14; P < 0.05] and low (HR = 1.75; 95% CI = 1.24-2.48; P < 0.005) activity groups for men, and in the low activity group (HR= 1.73; 95% CI = 1.28-2.33; P < 0.001) for women. Lower levels of activity were also associated with an increased likelihood of using health and personal social services 8 years after the initial interview, and an increased risk among men of having respiratory disease recorded as the primary cause of death. All models were adjusted for age, health and smoking status and weight category as measured at baseline. CONCLUSIONS: the results are consistent with the conclusion that, among elderly people, health gain resulting from higher customary physical activity levels can promote a longer and more independent later life.

Activities of Daily Living↗
PubMed1991

Validation of a three-month physical activity recall questionnaire with a seven-day food intake and physical activity diary.

We assessed the validity of a three-month physical activity questionnaire. The validation instrument was a seven-day self-report diary of physical activity and food intake, given to 113 randomly selected persons. We obtained Spearman correlations of 0.60, 0.48, and 0.91 and kappa scores of 0.36, 0.23, and 0.62 from the physical activity recall and diary for moderate, vigorous, and total activity. We conclude that the three-month recall questionnaire reasonably reflects activity in this community-based sample.

Diet↗