Comparison of two Actigraph models for assessing free-living physical activity in Indian adolescents

Abstract

This aim of this study was to compare the new Actigraph (GT1M) with the widely used Model 7164. Seven days of free-living physical activity were measured simultaneously using both the Model 7164 and GT1M in 30 Indian adolescents (mean age 15.8 years, s = 0.6). The GT1M was on average 9% lower per epoch than model 7164, thus a correction factor of 0.91 is suggested for comparison between the two monitors. The differences between monitors increased in magnitude with intensity of activity (P < 0.001) but remained randomly distributed (r = 0.01, P = 0.96). No significant difference was observed between monitors for time spent in moderate (P = 0.31) and vigorous (P = 0.34) physical activity when using the same epoch length. The Model 7164 classified less time as sedentary (P < 0.001) and more time as light-intensity activity (P < 0.001) than the GT1M. In conclusion, data from the GT1M can be compared with historical data using average counts per minute with a correction factor, and the two models might be comparable for assessing time spent in moderate to vigorous physical activity in children when using the same epoch length.     

Comparison of two Actigraph models for assessing free-living physical activity in Indian adolescents

This aim of this study was to compare the new Actigraph (GT1M) with the widely used Model 7164. Seven days of free-living physical activity were measured simultaneously using both the Model 7164 and GT1M in 30 Indian adolescents (mean age 15.8 years, s = 0.6). The GT1M was on average 9% lower per epoch than model 7164, thus a correction factor of 0.91 is suggested for comparison between the two monitors. The differences between monitors increased in magnitude with intensity of activity (P < 0.001) but remained randomly distributed (r = 0.01, P = 0.96). No significant difference was observed between monitors for time spent in moderate (P = 0.31) and vigorous (P = 0.34) physical activity when using the same epoch length. The Model 7164 classified less time as sedentary (P < 0.001) and more time as light-intensity activity (P < 0.001) than the GT1M. In conclusion, data from the GT1M can be compared with historical data using average counts per minute with a correction factor, and the two models might be comparable for assessing time spent in moderate to vigorous physical activity in children when using the same epoch length.     

The accuracy of the 24-h activity recall method for assessing sedentary behaviour: the physical activity measurement survey (PAMS) project

Sedentary behaviour (SB) has emerged as a modifiable risk factor, but little is known about measurement errors of SB. The purpose of this study was to determine the validity of 24-h Physical Activity Recall (24PAR) relative to SenseWear Armband (SWA) for assessing SB. Each participant (n = 1485) undertook a series of data collection procedures on two randomly selected days: wearing a SWA for full 24-h, and then completing the telephone-administered 24PAR the following day to recall the past 24-h activities. Estimates of total sedentary time (TST) were computed without the inclusion of reported or recorded sleep time. Equivalence testing was used to compare estimates of TST. Analyses from equivalence testing showed no significant equivalence of 24PAR for TST (90% CI: 443.0 and 457.6 min · day^–1) relative to SWA (equivalence zone: 580.7 and 709.8 min · day^–1). Bland–Altman plots indicated individuals that were extremely or minimally sedentary provided relatively comparable sedentary time between 24PAR and SWA. Overweight/obese and/or older individuals were more likely to under-estimate sedentary time than normal weight and/or younger individuals. Measurement errors of 24PAR varied by the level of sedentary time and demographic indicators. This evidence informs future work to develop measurement error models to correct for errors of self-reports.     

Evaluation of low-cost, objective instruments for assessing physical activity in 10-11-year-old children

This study compared step counts detected by four, low-cost, objective, physical-activity-assessment instruments and evaluated their ability to detect moderate-to-vigorous physical activity (MVPA) compared to the ActiGraph accelerometer (AG). Thirty-six 10-11-year-old children wore the NL-1000, Yamax Digiwalker SW 200, Omron HJ-151, and Walk4Life MVP concurrently with the AG during school hours on a single day. AG MVPA was derived from activity count data using previously validated cut points. Two of the evaluated instruments provided similar group mean MVPA and step counts compared to AG (dependent on cut point). Low-cost instruments may be useful for measurement of both MVPA and steps in children's physical activity interventions and program evaluation.     

Measuring physical activity in field studies: Comparison of a questionnaire, 24-hour recall and an accelerometer

Abstract

In a field setting, we compared a physical activity questionnaire (SQUASH), a 24-hour recall measure (Physical Activity Scale; PAS), and an accelerometer to: (1) quantify the amount of time spent in light, moderate, and vigorous physical activity; (2) calculate activity scores; and (3) categorize participants by physical activity tertiles. For 7 consecutive days, 103 participants (61% males, 39% females; mean age 36.8 years, mean body mass index 26.6 kg·m^?2) wore an accelerometer and completed the PAS. Immediately before these 7 days, the participants completed the SQUASH and underwent anthropometric measurements (weight and height). Time spent in light (<3 METs), moderate (3–6 METs), and vigorous (≥6 METs) activity was calculated. Significant correlations were observed between the PAS and accelerometer in the population as a whole (r=0.66, P<0.001), the males (r=0.76, P<0.001), participants of normal weight (r=0.62, P<0.05), and those who were overweight (r=0.53, P<0.01). Correlations between the SQUASH and accelerometer were only significant for males (r=0.62, P<0.05) and overweight individuals (r=0.40, P<0.05). Moderate agreement was observed between tertiles for the accelerometer and PAS activity scores in the overall population (weighted kappa =0.47; 95% confidence interval =0.27–0.67) but not between the accelerometer and SQUASH. In conclusion, a 7-day administration of the PAS is a useful measure for classification of physical activity in the population studied. The SQUASH has practical advantages in terms of convenience of administration, but its usefulness in estimating physical activity is limited.     

Validating the multimedia activity recall for children and adolescents in a large New Zealand sample

Abstract

The aim of the study was to validate the self-report Multimedia Activity Recall for Children and Adolescents (MARCA) against accelerometry for the assessment of physical activity in New Zealand children. Participants (n = 716, 10–18 years) recalled 3–4 days of activity using the MARCA and underwent a partially overlapping 7-day accelerometry protocol during a national survey. Spearman correlation coefficients (ρ) assessed the association between accelerometer-derived counts per minute and MARCA-derived physical activity level and time in locomotion. Both data sources estimated time spent in light and moderate–vigorous physical activity. Association and agreement between methods for light physical activity and moderate–vigorous physical activity was assessed using correlations and Bland–Altman plots respectively, and paired t-tests conducted. Accelerometer-derived activity counts were moderately correlated with both MARCA-derived physical activity level and locomotion (ρ = 0.38, P < 0.0001). The correlation between methods was –0.14 for light physical activity and 0.28 for moderate–vigorous physical activity (P < 0.0001). The MARCA overestimated moderate–vigorous physical activity compared with accelerometry (120 min, P < 0.0001), which increased as moderate–vigorous physical activity time increased. Some sex and ethnicity (Māori [indigenous] versus non-Māori) differences were observed. Overall, the MARCA indicated moderate validity for assessment of physical activity level, locomotion and moderate–vigorous physical activity and poor validity for assessment of light physical activity. This was comparable to other self-report tools. The MARCA has utility for future large-scale research.     

A prospective study of pedometer-determined physical activity and physical self-perceptions in children

There have been limited prospective studies investigating physical activity and physical self-perceptions in children. In this investigation, mean steps/day did not significantly change from late elementary to junior high for either boys or girls; however; boys accumulated more steps both at baseline and follow-up. Physical self-perception measures were significantly related to changes in steps/day and accounted for 21% (15% adjusted) of the variance after controlling for demographic/biological variables, R2 change = .21, adjusted R2 change = .15, F (5,88) = 4.66, p < .001. Sport competence emerged as the most important predictor t (88) = -3.76, p < .001, and was inversely related to physical activity change. The lack of opportunities to participate in sport activities normally found at the onset of adolescence may help explain this unexpected result.     

Validation of a short physical activity recall questionnaire completed by Spanish adolescents

Abstract

Self-report recall questionnaires are commonly used to measure physical activity in children and adolescents. However, they have been shown to have low to moderate validity, mainly due to inaccuracies in recall activity. The purpose of the present study was to determine the reliability and validity of an adapted version of the Assessment of Physical Activity Levels Questionnaire (APALQ) among a sample of Spanish adolescents. Test–retest reliability of the APALQ was assessed using a sample of 150 adolescents (72 males, 78 females), aged 13.6±1.1 years, who answered the APALQ twice within 7 days. Criterion validity was assessed using a sample of 77 adolescents (50 males, 27 females), aged 13.6±1.1 years, by comparing the APALQ against the Computer Science and Application (CSA) monitor. All participants were volunteers recruited from local schools in the Aragon region of Spain. Test–retest reliability for all items was high with intra-class coefficients of 0.77 for boys and 0.74 for girls. The APALQ demonstrated modest criterion validity with Pearson correlation coefficients (r) ranging from 0.53 between Physical Activity Index (PAI) and CSA minutes of moderate and vigorous physical activity, and 0.47 between PAI and CSA steps per day. When the data were analysed by gender, girls had higher correlations than boys (P < 0.01). The Spanish APALQ seems to be a valid and reliable short self-report physical activity questionnaire.     

The measurement of physical activity in young children

Two studies were conducted to determine the validity of various measures of physical activity in young children. In Study 1, 21 preschool children were utilized to explore how well measures of children's activity obtained from parents, teachers, and the children predicted observed behavior at school and in the home. Study 2 (n = 51 preschool children) focused on the predictive validity of the Caltrac motion sensor. In both studies, detailed minute-by-minute ratings of children's activity in Study 1 were generally ineffective in predicting observed physical activity. Children's activity preferences, however, were significantly related to the proportion of high intensity physical activity performed. In Study 2, there was a significant relationship (r = .86, p less than .0001) between Caltrac readings and observed physical activity. This correlation was similar for boys and girls, normal and overweight children, and younger and older children. These findings suggest that the Caltrac monitor may provide a valid index of individual differences in physical activity in young children.     

Creating community, assessing need: preparing for a community physical activity intervention

This paper describes the preliminary steps needed to begin a community physical activity intervention in a rural context, including forming a community coalition and assessing values, beliefs, and knowledge about physical activity. A random mail survey (N = 171) indicated relatively high activity rates, and perceived barriers consistent with the literature (time, program convenience, safety issues). Perceived benefits included improving/sustaining health and looking better/improving appearance. Five focus groups added additional barriers (e.g., physical isolation, lack of transportation). Residents were unaware of many existing services and indicated a desire for more walking trails, health-related activities, and low-cost exercise facilities. The discussion focuses on the importance of establishing a community coalition and implications for future program development and research.     

Adiposity,physical activity and neuromuscular performance in children

We investigated the associations of body fat percentage (BF%), objectively assessed moderate-to-vigorous physical activity (MVPA) and different types of physical activity assessed by a questionnaire with neuromuscular performance. The participants were 404 children aged 6–8 years. BF% was assessed using dual-energy x-ray absorptiometry and physical activity by combined heart rate and movement sensing and a questionnaire. The results of 50-m shuttle run, 15-m sprint run, hand grip strength, standing long jump, sit-up, modified flamingo balance, box-and-block and sit-and-reach tests were used as measures of neuromuscular performance. Children who had a combination of higher BF% and lower levels of physical activity had the poorest performance in 50-m shuttle run, 15-m sprint run and standing long jump tests. Higher BF% was associated with slower 50-m shuttle run and 15-m sprint times, shorter distance jumped in standing long jump test, fewer sit-ups, more errors in balance test and less cubes moved in box-and-block test. Higher levels of physical activity and particularly MVPA assessed objectively by combined accelerometer and heart rate monitor were related to shorter 50-m shuttle run and 15-m sprint times. In conclusion, higher BF% and lower levels of physical activity and particularly the combination of these two factors were associated with worse neuromuscular performance.     

Calibration of two objective measures of physical activity for children

A calibration study was conducted to determine the threshold counts for two commonly used accelerometers, the ActiGraph and the Actical, to classify activities by intensity in children 5 to 8 years of age. Thirty-three children wore both accelerometers and a COSMED portable metabolic system during 15 min of rest and then performed up to nine different activities for 7 min each, on two separate days in the laboratory. Oxygen consumption was measured on a breath-by-breath basis, and accelerometer data were collected in 15-s epochs. Using receiver operating characteristic curve (ROC) analysis, cutpoints that maximised both sensitivity and specificity were determined for sedentary, moderate and vigorous activities. For both accelerometers, discrimination of sedentary behaviour was almost perfect, with the area under the ROC curve at or exceeding 0.98. For both the ActiGraph and Actical, the discrimination of moderate (0.85 and 0.86, respectively) and vigorous activity (0.83 and 0.86, respectively) was acceptable, but not as precise as for sedentary behaviour. This calibration study, using indirect calorimetry, suggests that the two accelerometers can be used to distinguish differing levels of physical activity intensity as well as inactivity among children 5 to 8 years of age.     

Health-enhancing physical activity and sedentary behaviour in children and adolescents

We provide a wide-ranging review of health-related physical activity in children and adolescents using a behavioural epidemiology framework. In contrast to many other reviews, we highlight issues associated with true sedentary behaviours alongside physically active behaviours. Specifically, we review the evidence concerning the links between physical activity and cardiovascular disease, overweight and obesity, psychosocial measures, type II diabetes, and skeletal health. Although the evidence is unconvincing at times, several factors lead to the conclusion that promoting physical activity in youth is desirable. A review of the prevalence of physical activity and sedentary behaviours shows that many young people are active, but this declines with age. A substantial number are not adequately active for health benefits and current trends in juvenile obesity are a cause for concern. Prevalence data on sedentary behaviours are less extensive but suggest that total media use by young people has not changed greatly in recent years. Most children and adolescents do not exceed recommended daily hours of TV viewing. Physical activity is unrelated to TV viewing. We also identified the key determinants of physical activity in this age group, highlighting demographic, biological, psychological, behavioural, social and environmental determinants. Interventions were considered for school, family and community environments. Finally, policy recommendations are offered for the education, governmental, sport and recreation, health, and mass media sectors.     

Health-enhancing physical activity and sedentary behaviour in children and adolescents

We provide a wide-ranging review of health-related physical activity in children and adolescents using a behavioural epidemiology framework. In contrast to many other reviews, we highlight issues associated with true sedentary behaviours alongside physically active behaviours. Specifically, we review the evidence concerning the links between physical activity and cardiovascular disease, overweight and obesity, psychosocial measures, type II diabetes, and skeletal health. Although the evidence is unconvincing at times, several factors lead to the conclusion that promoting physical activity in youth is desirable. A review of the prevalence of physical activity and sedentary behaviours shows that many young people are active, but this declines with age. A substantial number are not adequately active for health benefits and current trends in juvenile obesity are a cause for concern. Prevalence data on sedentary behaviours are less extensive but suggest that total media use by young people has not changed greatly in recent years. Most children and adolescents do not exceed recommended daily hours of TV viewing. Physical activity is unrelated to TV viewing. We also identified the key determinants of physical activity in this age group, highlighting demographic, biological, psychological, behavioural, social and environmental determinants. Interventions were considered for school, family and community environments. Finally, policy recommendations are offered for the education, governmental, sport and recreation, health, and mass media sectors.     

Limitations of cadence-based walking for assessing bouts of moderate-to vigorous-intensity physical activity under free-living conditions

Abstract

The purpose of the present investigation was to examine the relationship between the accumulation of 1000 steps in 10 minutes (1K) and 3000 steps in 30 minutes (3K) with the amount and intensity of daily physical activity. Thirty-three adults (16 males and 17 females, 53 ± 19 years) wore an accelerometer (Lifecorder) for seven consecutive days in order to determine the number of steps and the time spent in physical activity at light intensity (LPA), moderate intensity (MPA), vigorous intensity (VPA) and moderate to vigorous intensity (MVPA). Furthermore, based on the minute-by-minute stepping rate, the number, intensity and duration of walking bouts (1K and 3K) were evaluated. The daily number of steps, LPA, MPA and VPA were significantly higher on the days with 1K or 3K compared with that observed on the days without 1K or 3K (P <0.05). The duration of 1K was not found to be correlated with an MVPA >10 minutes. An MVPA >10 minutes was less than 2 min · day^?1 on the days with 1K or 3K. Therefore, it is doubtful that the concept of cadence is an alternative indicator for the commonly used definition of MVPA. It remains unclear whether participation in 1K and 3K guarantees that an individual will meet the current MVPA guidelines.     

Validity and reliability of measures assessing social-cognitive determinants of physical activity in low-active Australian adults

This cross-sectional study of 504 community-dwelling Australian adults (328 females, 176 males, mean age 50.8 ± 13.0 years) sought to examine the reliability and validity of measurement scales for physical activity (PA) self-efficacy and outcome expectations. Participants completed demographic and anthropometric measurements, and a 23-item psychosocial questionnaire pertinent to an intervention target of 10,000 steps per day. Exploratory (n = 252) and confirmatory (n = 252) factor analyses were conducted to determine psychometric properties of the measures. Based on theory and goodness-of-fit indices, six factors were extracted from the questionnaire: PA self-efficacy; PA barriers self-efficacy (including general, personal, and conflict); and physical and mental outcome expectations. From confirmatory factor analysis, the model demonstrated good data fit in four out of five indices: CFI = 0.99; TLI = 0.99; SRMR = 0.03; RMSEA = 0.03, 90%CI = 0.01–0.05, χ² = 113.14 (88), p = 0.04; including good fit by sex, age, weight status, education, and birth country. PA interventions can employ our psychometrically sound social cognitive measures.     

The physical activity, fitness and health of children

It is clear that, despite their natural tendencies, children have become less physically active in recent decades, with children today expending approximately 600 kcal days' less than their counterparts 50 years ago. Although the health consequences of a reduced energy expenditure in adults is well documented, there is little direct evidence linking sedentariness with health in children. However, three main benefits arising from adequate childhood physical activity have been postulated. The first is direct improvements in childhood health status; evidence is accumulating that more active children generally display healthier cardiovascular profiles, are leaner and develop higher peak bone masses than their less active counterparts. Secondly, there is a biological carry-over effect into adulthood, whereby improved adult health status results from childhood physical activity. In particular, childhood obesity may be a precursor for a range of adverse health effects in adulthood, while higher bone masses in young people reduce the risk of osteoporosis in old age. Finally, there may be a behavioural carry-over into adulthood, whereby active children are more likely to become more active (healthy) adults. However, supporting evidence for this assertion is weak. Given this background, recent health guidelines suggesting that children should accumulate 60 min of moderate-intensity physical activity every day--supplemented by regular activities that promote strength flexibility and bone strength--appear to be justified. Future developments should include the implementation of large-scale, longitudinal studies spanning childhood and young adulthood, the further refinement of tools for measuring physical activity accurately in young people, and research into the relative strength of association between fitness--as well as activity--and health in children.     

The physical activity,fitness and health of children

It is clear that, despite their natural tendencies, children have become less physically active in recent decades, with children today expending approximately 600 kcal· day -1 less than their counterparts 50 years ago. Although the health consequences of a reduced energy expenditure in adults is well documented, there is little direct evidence linking sedentariness with health in children. However, three main benefits arising from adequate childhood physical activity have been postulated. The first is direct improvements in childhood health status; evidence is accumulating that more active children generally display healthier cardiovascular profiles, are leaner and develop higher peak bone masses than their less active counterparts. Secondly, there is a biological carryover effect into adulthood, whereby improved adult health status results from childhood physical activity. In particular, childhood obesity may be a precursor for a range of adverse health effects in adulthood, while higher bone masses in young people reduce the risk of osteoporosis in old age. Finally, there may be a behavioural carryover into adulthood, whereby active children are more likely to become more active (healthy) adults. However, supporting evidence for this assertion is weak. Given this background, recent health guidelines suggesting that children should accumulate 60 min of moderate-intensity physical activity every day - supplemented by regular activities that promote strength flexibility and bone strength - appear to be justified. Future developments should include the implementation of large-scale, longitudinal studies spanning childhood and young adulthood, the further refinement of tools for measuring physical activity accurately in young people, and research into the relative strength of association between fitness - as well as activity - and health in children.