Fully proportional actigraphy: A new instrument

Tryon, Warren W.; Williams, Robert E.

doi:10.3758/bf03200519

Cited by 166 publications

(147 citation statements)

References 28 publications

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“…Habitual physical activity was assessed with the Computer Science & Applications (CSA) accelerometer, now also known as the MTI actigraph (Manufacturing Technology, Fort Walton Beach, FL). The CSA is a uni-axial piezo-electric accelerometer with a dynamic range of Ϯ2.13g and a frequencydependent bandwidth filter that can be regarded as a mathematical weighting function (19,20). The CSA samples acceleration at 10 Hz and integrates this over the user-defined epoch.…”

Section: Data Collectionmentioning

confidence: 99%

Features of the Metabolic Syndrome Are Associated With Objectively Measured Physical Activity and Fitness in Danish Children

et al. 2004

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OBJECTIVE -Features of the metabolic syndrome are becoming increasingly evident in children. Decreased physical activity is likely to be an important etiological factor, as shown previously for subjective measures of physical activity in selected groups. The purpose of this study was to examine the relationship between the metabolic syndrome and objectively measured physical activity and whether fitness modified this relationship. (MTI actigraph) worn at the hip for at least 3 days (Ն10 h/day) and fitness with a maximal bike test. As outcomes, we measured sitting systolic and diastolic blood pressure, degree of adiposity (sum of four skinfolds), and, finally, insulin, glucose, triglicerides, and HDL cholesterol in fasting blood samples. The outcome variables were statistically normalized and expressed as the number of SDs from the mean. (i.e., Z scores). A metabolic syndrome risk score was computed as the mean of these Z scores. Multiple linear regression was used to test the association between physical activity and metabolic risk, adjusted primarily for age, sex, sexual maturation, ethnicity, parental smoking, socioeconomic factors, and the Computer Science & Applications unit, as well as for fitness. Robust SEs were computed by clustering on school. RESEARCH DESIGN AND METHODSRESULTS -All children were in the nondiabetic range of fasting glucose. Metabolic risk was inversely related to physical activity (P ϭ 0.008). The relationship was weakened after adjustment for fitness, but there was a significantly positive interaction between physical activity and fitness.CONCLUSIONS -Physical activity is inversely associated with metabolic risk, independently of potential confounders. The interaction between physical activity and fitness suggests that the potential beneficial effect of activity may be greatest in children with lower cardiorespiratory fitness.

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Section: Data Collectionmentioning

confidence: 99%

Features of the Metabolic Syndrome Are Associated With Objectively Measured Physical Activity and Fitness in Danish Children

et al. 2004

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“…45 g) and provides detailed information about the intensity, frequency and duration of PA with sufficient storage capacity for monitoring PA minute-by-minute for 3 weeks. The technical specifications of the monitor are described elsewhere 6 . Briefly, accelerations ranging in magnitude from 0.05 to 2.0 g are measured by a piezoelectric sensor, sampled at 10 Hz, and then summed over a selected time interval (epoch).…”

Section: Subjects and Designmentioning

confidence: 99%

Criterion-related validity of the last 7-day, short form of the International Physical Activity Questionnaire in Swedish adults

Ekelund

Sepp

Brage

et al. 2006

Public Health Nutr.

392

327

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Objective: To examine the validity of the short, last 7-day, self-administered form of the International Physical Activity Questionnaire (IPAQ). Design: All subjects wore an accelerometer for seven consecutive days and completed the IPAQ questionnaire on the eighth day. Criterion validity was assessed by linear regression analysis and by modified Bland -Altman analysis. Specificity and sensitivity were calculated for classifying respondents according to the physical activity guidelines of the American College of Sports Medicine/Centers for Disease Control and Prevention. Setting: Workplaces in Uppsala, Sweden. Subjects: One hundred and eighty-five (87 males) participants, aged 20 to 69 years. Results: Total self-reported physical activity (PA) (MET-min day 21 ) was significantly correlated with average intensity of activity (counts min 21 ) from accelerometry (r ¼ 0.34, P , 0.001). Gender, age, education and body mass index did not affect this relationship. Further, subcomponents of self-reported PA (time spent sitting, time in PA, time in moderate and vigorous activity (MVPA)) were significantly correlated with objectively measured PA (P , 0.05). Self-reported time in PA was significantly different from time measured by accelerometry (mean difference: 2 25.9 min day 21 ; 95% limits of agreement: 2 172 to 120 min day 21 ; P , 0.001). IPAQ identified 77% (specificity) of those who met the current PA guidelines of accumulating more than 30 min day 21 in MVPA as determined by accelerometry, whereas only 45% (sensitivity) of those not meeting the guidelines were classified correctly. Conclusions: Our results indicate that the short, last 7-days version of the IPAQ has acceptable criterion validity for use in Swedish adults. However, the IPAQ instrument significantly overestimated self-reported time spent in PA. The specificity to correctly classify people achieving current PA guidelines was acceptable, whereas the sensitivity was low.

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“…The CSA is a uniaxial piezoelectric accelerometer with a dynamic range of 72.13g and a frequency-dependent bandwidth filter, which can be regarded as a mathematical weighting function. 19,20 The CSA samples acceleration at 10 Hz and Relationship between physical activity and insulin resistance in Danish children S Brage et al integrates this over the user-defined epoch. In this study, the CSA was mailed to the children, preprogrammed to start at 0800 the following morning.…”

Section: Data Collectionmentioning

confidence: 99%

Objectively measured physical activity correlates with indices of insulin resistance in Danish children.

et al. 2004

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OBJECTIVE:To explore the association between measures of insulin resistance with objectively assessed physical activity. DESIGN: School-based, cross-sectional study. SUBJECTS: A randomly selected sample of 589 children (310 girls, 279 boys, mean (standard deviations, s.d.) age ¼ 9.7 (0.44) y, weight ¼ 33.6 (6.4) kg, height ¼ 1.39 (0.06) m) from Denmark. METHODS: Fasting blood samples were analysed for serum insulin and glucose. Physical activity was measured with the uniaxial Computer Science and Applications (CSA) model 7164 accelerometer, worn for at least 3 days (Z10 h day À1 ). Adiposity was assessed by the sum of four skinfolds. Multiple linear regression were performed to model insulin and glucose from average CSA output, adjusted for age, gender, puberty, ethnicity, birth weight, parental smoking, socioeconomic group, and CSA unit. In addition, we adjusted for skinfold thickness. RESULTS: Mean fasting serum glucose ranged from 4.1 to 6.5 mmol l À1 with a mean (s.d.) of 5.1 (0.37) mmol l À1 . Fasting insulin was negatively correlated with CSA output on levels of adjustment. Fasting glucose was not significantly associated with physical activity. However, in girls both indices of insulin resistance were significantly related to activity, whereas in boys none of the associations were significant. CONCLUSION: Physical activity is inversely associated with fasting insulin in the nondiabetic range of fasting glucose. The relationship was stronger for insulin than for glucose, indicating compensatory action by the b cells. Our data emphasise the importance of physical activity in children for the maintenance of metabolic control.

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Fully proportional actigraphy: A new instrument

Cited by 166 publications

References 28 publications

Features of the Metabolic Syndrome Are Associated With Objectively Measured Physical Activity and Fitness in Danish Children

Features of the Metabolic Syndrome Are Associated With Objectively Measured Physical Activity and Fitness in Danish Children

Criterion-related validity of the last 7-day, short form of the International Physical Activity Questionnaire in Swedish adults

Objectively measured physical activity correlates with indices of insulin resistance in Danish children.

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