Willem van Mechelen

Sedentary Behaviors and Health Outcomes Among Adults: A Systematic Review of Prospective Studies

CONTEXT Nowadays, people spend a substantial amount of time per day on sedentary behaviors and it is likely that the time spent sedentary will continue to rise. To date, there is no review of prospective studies that systematically examined the relationship between diverse sedentary behaviors and various health outcomes among adults. PURPOSE This review aimed to systematically review the literature as to the relationship between sedentary behaviors and health outcomes considering the methodologic quality of the studies. EVIDENCE ACQUISITION In February 2010, a search for prospective studies was performed in diverse electronic databases. After inclusion, in 2010, the methodologic quality of each study was assessed. A best-evidence synthesis was applied to draw conclusions. EVIDENCE SYNTHESIS 19 studies were included, of which 14 were of high methodologic quality. Based on inconsistency in findings among the studies and lack of high-quality prospective studies, insufficient evidence was concluded for body weight-related measures, CVD risk, and endometrial cancer. Further, moderate evidence for a positive relationship between the time spent sitting and the risk for type 2 diabetes was concluded. Based on three high-quality studies, there was no evidence for a relationship between sedentary behavior and mortality from cancer, but strong evidence for all-cause and CVD mortality. CONCLUSIONS Given the trend toward increased time in sedentary behaviors, additional prospective studies of high methodologic quality are recommended to clarify the causal relationships between sedentary behavior and health outcomes. Meanwhile, evidence to date suggests that interventions aimed at reducing sedentary behavior are needed.

The Effect of a Proprioceptive Balance Board Training Program for the Prevention of Ankle Sprains A Prospective Controlled Trial

Background Ankle sprains are the most common injuries in a variety of sports. Hypothesis A proprioceptive balance board program is effective for prevention of ankle sprains in volleyball players. Study Design Prospective controlled study. Methods There were 116 male and female volleyball teams followed prospectively during the 2001-2002 season. Teams were randomized by 4 geographical regions to an intervention group (66 teams, 641 players) and control group (50 teams, 486 players). Intervention teams followed a prescribed balance board training program; control teams followed their normal training routine. The coaches recorded exposure on a weekly basis for each player. Injuries were registered by the players within 1 week after onset. Results Significantly fewer ankle sprains in the intervention group were found compared to the control group (risk difference = 0.4/1000 playing hours; 95% confidence interval, 0.1-0.7). A significant reduction in ankle sprain risk was found only for players with a history of ankle sprains. The incidence of overuse knee injuries for players with history of knee injury was increased in the intervention group. History of knee injury may be a contraindication for proprioceptive balance board training. Conclusions Use of proprioceptive balance board program is effective for prevention of ankle sprain recurrences.

Physical activity questionnaires for adults: a systematic review of measurement properties

Many questionnaires have been developed to measure physical activity (PA), but an overview of the measurement properties of PA questionnaires is lacking. A summary of this information is useful for choosing the best questionnaire available. Therefore, the objective of this study was to evaluate and compare measurement properties of self-administered questionnaires assessing PA in adults. We searched MEDLINE, EMBASE and SportDiscus®, using ‘exercise’, ‘physical activity’, ‘motor activity’ and ‘questionnaire’ as keywords. We included studies that evaluated the measurement properties of self-report questionnaires assessing PA. Article selection, data extraction and quality assessment were performed by two independent reviewers. The quality and results of the studies were evaluated using the Quality Assessment of Physical Activity Questionnaires (QAPAQ) checklist. Construct validity, reliability and responsiveness were rated as positive, negative or indeterminate, depending on the methods and results. We included 85 (versions of) questionnaires. Overall, the quality of the studies assessing measurement properties of PA questionnaires was rather poor. Information on content validity was mostly lacking. Construct validity was assessed in 76 of the questionnaires, mostly by correlations with accelerometer data, maximal oxygen uptake or activity diaries. Fifty-one questionnaires were tested for reliability. Only a few questionnaires had sufficient construct validity and reliability, but these need to be further validated. Responsiveness was studied for only two questionnaires and was poor. There is a clear lack of standardization of PA questionnaires, resulting in many variations of questionnaires. No questionnaire or type of questionnaire for assessing PA was superior and therefore could not be strongly recommended above others. In the future, more attention should be paid to the methodology of studies assessing measurement properties of PA questionnaires and the quality of reporting.

Effect of school based physical activity programme (KISS) on fitness and adiposity in primary schoolchildren: cluster randomised controlled trial

Objective To assess the effectiveness of a school based physical activity programme during one school year on physical and psychological health in young schoolchildren. Design Cluster randomised controlled trial. Setting 28 classes from 15 elementary schools in Switzerland randomly selected and assigned in a 4:3 ratio to an intervention (n=16) or control arm (n=12) after stratification for grade (first and fifth grade), from August 2005 to June 2006. Participants 540 children, of whom 502 consented and presented at baseline. Intervention Children in the intervention arm (n=297) received a multi-component physical activity programme that included structuring the three existing physical education lessons each week and adding two additional lessons a week, daily short activity breaks, and physical activity homework. Children (n=205) and parents in the control group were not informed of an intervention group. For most outcome measures, the assessors were blinded. Main outcome measures Primary outcome measures included body fat (sum of four skinfolds), aerobic fitness (shuttle run test), physical activity (accelerometry), and quality of life (questionnaires). Secondary outcome measures included body mass index and cardiovascular risk score (average z score of waist circumference, mean blood pressure, blood glucose, inverted high density lipoprotein cholesterol, and triglycerides). Results 498 children completed the baseline and follow-up assessments (mean age 6.9 (SD 0.3) years for first grade, 11.1 (0.5) years for fifth grade). After adjustment for grade, sex, baseline values, and clustering within classes, children in the intervention arm compared with controls showed more negative changes in the z score of the sum of four skinfolds (−0.12, 95 % confidence interval −0.21 to −0.03; P=0.009). Likewise, their z scores for aerobic fitness increased more favourably (0.17, 0.01 to 0.32; P=0.04), as did those for moderate-vigorous physical activity in school (1.19, 0.78 to 1.60; P<0.001), all day moderate-vigorous physical activity (0.44, 0.05 to 0.82; P=0.03), and total physical activity in school (0.92, 0.35 to 1.50; P=0.003). Z scores for overall daily physical activity (0.21, −0.21 to 0.63) and physical quality of life (0.42, −1.23 to 2.06) as well as psychological quality of life (0.59, −0.85 to 2.03) did not change significantly. Conclusions A school based multi-component physical activity intervention including compulsory elements improved physical activity and fitness and reduced adiposity in children. Trial registration Current Controlled Trials ISRCTN15360785.

Review and special articleSedentary Behaviors and Health Outcomes Among Adults: A Systematic Review of Prospective Studies

CONTEXT Nowadays, people spend a substantial amount of time per day on sedentary behaviors and it is likely that the time spent sedentary will continue to rise. To date, there is no review of prospective studies that systematically examined the relationship between diverse sedentary behaviors and various health outcomes among adults. PURPOSE This review aimed to systematically review the literature as to the relationship between sedentary behaviors and health outcomes considering the methodologic quality of the studies. EVIDENCE ACQUISITION In February 2010, a search for prospective studies was performed in diverse electronic databases. After inclusion, in 2010, the methodologic quality of each study was assessed. A best-evidence synthesis was applied to draw conclusions. EVIDENCE SYNTHESIS 19 studies were included, of which 14 were of high methodologic quality. Based on inconsistency in findings among the studies and lack of high-quality prospective studies, insufficient evidence was concluded for body weight-related measures, CVD risk, and endometrial cancer. Further, moderate evidence for a positive relationship between the time spent sitting and the risk for type 2 diabetes was concluded. Based on three high-quality studies, there was no evidence for a relationship between sedentary behavior and mortality from cancer, but strong evidence for all-cause and CVD mortality. CONCLUSIONS Given the trend toward increased time in sedentary behaviors, additional prospective studies of high methodologic quality are recommended to clarify the causal relationships between sedentary behavior and health outcomes. Meanwhile, evidence to date suggests that interventions aimed at reducing sedentary behavior are needed.

Psychosocial risk factors for neck pain: A systematic review

BACKGROUND Neck pain, which is assumed to be a multifactorial disease, is a major problem in modern society. METHODS To identify the most important psychosocial risk factors for neck pain, a systematic review of the literature was carried out. The methodological quality of all studies in the review was assessed. Four levels of evidence were defined to assess the strength of evidence for potential risk factors for neck pain (strong, moderate, some or inconclusive evidence). RESULTS Some evidence was found for a positive relationship between neck pain and high quantitative job demands, low social (coworker) support, low job control, high and low skill discretion and low job satisfaction. Inconclusive evidence was found for high job strain, low supervisor support, conflicts at work, low job security, and limited rest break opportunities. CONCLUSIONS The procedure of the assessment of the methodological quality and the rating system applied to distinguish between high- and low-score studies, had a considerable influence on the level of evidence, indicating that changes in this procedure may have a major impact on the overall conclusions of this review.

Physical Activity and Performance at School A Systematic Review of the Literature Including a Methodological Quality Assessment

OBJECTIVE To describe the prospective relationship between physical activity and academic performance. DATA SOURCES Prospective studies were identified from searches in PubMed, PsycINFO, Cochrane Central, and Sportdiscus from 1990 through 2010. STUDY SELECTION We screened the titles and abstracts for eligibility, rated the methodological quality of the studies, and extracted data. MAIN EXPOSURE Studies had to report at least 1 physical activity or physical fitness measurement during childhood or adolescence. MAIN OUTCOME MEASURES Studies had to report at least 1 academic performance or cognition measure during childhood or adolescence. RESULTS We identified 10 observational and 4 intervention studies. The quality score of the studies ranged from 22% to 75%. Two studies were scored as high quality. Methodological quality scores were particularly low for the reliability and validity of the measurement instruments. Based on the results of the best-evidence synthesis, we found evidence of a significant longitudinal positive relationship between physical activity and academic performance. CONCLUSIONS Participation in physical activity is positively related to academic performance in children. Because we found only 2 high-quality studies, future high-quality studies are needed to confirm our findings. These studies should thoroughly examine the dose-response relationship between physical activity and academic performance as well as explanatory mechanisms for this relationship.

Tracking of activity and fitness and the relationship with cardiovascular disease risk factors

PURPOSE To analyze tracking of daily physical activity and physical fitness (both cardiopulmonary [VO2max] and neuromotor fitness) and the longitudinal relationship with biological risk factors for cardiovascular disease (CVD), i.e., total serum cholesterol (TC), high-density lipoprotein (HDL), the TC:HDL ratio, systolic and diastolic blood pressure, and the sum of four skinfolds. METHODS Data were obtained from the Amsterdam Growth and Health Study; an observational longitudinal study with six repeated measurements over a period from 13 to 27 yr of age (N = 181). The statistical analyses were carried out with generalized estimating equations. RESULTS Low to moderate tracking (both stability and predictability of early measurements) was observed for daily physical activity and VO2max, whereas good tracking was observed for neuromotor fitness. Daily physical activity was positively related to HDL (P < 0.01), and inversely to the TC:HDL ratio (P < 0.05) and to the sum of four skinfolds (P < 0.01). VO2max was also inversely related to the TC:HDL ratio (P < 0.01) and to the sum of four skinfolds (P < 0.01). In addition, VOmax was also inversely related to TC (P < 0.01). Neuromotor fitness was inversely related to the sum of four skinfolds (P < 0.01), and positively to systolic blood pressure (P < 0.01). CONCLUSIONS The longitudinal development of physical activity and VO2max were related to a healthy CVD risk profile. For the development of neuromotor fitness, the picture was less clear. The relationships among physical activity, physical fitness, and lipoproteins and blood pressure were highly influenced by body fatness.

The economic burden of physical inactivity: a global analysis of major non-communicable diseases

BACKGROUND The pandemic of physical inactivity is associated with a range of chronic diseases and early deaths. Despite the well documented disease burden, the economic burden of physical inactivity remains unquantified at the global level. A better understanding of the economic burden could help to inform resource prioritisation and motivate efforts to increase levels of physical activity worldwide. METHODS Direct health-care costs, productivity losses, and disability-adjusted life-years (DALYs) attributable to physical inactivity were estimated with standardised methods and the best data available for 142 countries, representing 93·2% of the worlds population. Direct health-care costs and DALYs were estimated for coronary heart disease, stroke, type 2 diabetes, breast cancer, and colon cancer attributable to physical inactivity. Productivity losses were estimated with a friction cost approach for physical inactivity related mortality. Analyses were based on national physical inactivity prevalence from available countries, and adjusted population attributable fractions (PAFs) associated with physical inactivity for each disease outcome and all-cause mortality. FINDINGS Conservatively estimated, physical inactivity cost health-care systems international

Physical Activity Questionnaires for Youth: A Systematic Review of Measurement Properties

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