Accelerometer data reduction: a comparison of four reduction algorithms on select outcome variables

Effects and costs of real-time cardiac telerehabilitation: randomised controlled non-inferiority trial

Objective

Compare the effects and costs of remotely monitored exercise-based cardiac telerehabilitation (REMOTE-CR) with centre-based programmes (CBexCR) in adults with coronary heart disease (CHD).

Methods

Participants were randomised to receive 12 weeks of telerehabilitation or centre-based rehabilitation. REMOTE-CR provided individualised exercise prescription, real-time exercise monitoring/coaching and theory-based behavioural strategies via a bespoke telerehabilitation platform; CBexCR provided individualised exercise prescription and coaching via established rehabilitation clinics. Outcomes assessed at baseline, 12 and/or 24 weeks included maximal oxygen uptake (V̇O₂max, primary) modifiable cardiovascular risk factors, exercise adherence, motivation, health-related quality of life and programme delivery, hospital service utilisation and medication costs. The primary hypothesis was a non-inferior between-group difference in V̇O₂max at 12 weeks (inferiority margin=−1.25 mL/kg/min); inferiority margins were not set for secondary outcomes.

Results

162 participants (mean 61±12.7 years, 86% men) were randomised. V̇O₂ max was comparable in both groups at 12 weeks and REMOTE-CR was non-inferior to CBexCR (REMOTE-CR-CBexCR adjusted mean difference (AMD)=0.51 (95% CI −0.97 to 1.98) mL/kg/min, p=0.48). REMOTE-CR participants were less sedentary at 24 weeks (AMD=−61.5 (95% CI −117.8 to −5.3) min/day, p=0.03), while CBexCR participants had smaller waist (AMD=1.71 (95% CI 0.09 to 3.34) cm, p=0.04) and hip circumferences (AMD=1.16 (95% CI 0.06 to 2.27) cm, p=0.04) at 12 weeks. No other between-group differences were detected. Per capita programme delivery (NZD1130/GBP573 vs NZD3466/GBP1758) and medication costs (NZD331/GBP168 vs NZD605/GBP307, p=0.02) were lower for REMOTE-CR. Hospital service utilisation costs were not statistically significantly different (NZD3459/GBP1754 vs NZD5464/GBP2771, p=0.20).

Conclusion

REMOTE-CR is an effective, cost-efficient alternative delivery model that could—as a complement to existing services—improve overall utilisation rates by increasing reach and satisfying unique participant preferences.

The relationship between objectively-measured attributes of the built environment and selected cardiovascular risk factors in a South African urban setting

BACKGROUND

Evidence concerning the relationship between objectively-measured attributes of the built environment with cardio-metabolic risk in populations from lower- and middle-income countries is lacking. In this paper, we describe the association between the objectively-measured built environment with body mass index, blood pressure and physical activity in adult South Africans.

METHODS

This cross-sectional study included 341 adults aged ≥35 years drawn from the Cape Town arm of the Prospective Urban Rural Epidemiology (PURE) cohort study. All Cape Town PURE participants were invited to take part in the study. Actigraph GT3X accelerometer and Geographic Information Systems were used to measure physical activity and built environment attributes (community center, shopping center and taxi rank).

RESULTS

In age and sex adjusted models (reference 500 m), access to community centers (1000 m) was positively related to body mass index [beta 4.70 (95%CI: 2.06 to 7.34)] and diastolic blood pressure [4.97 (0.00 to 9.95)]. Distance from a community center (1600 m) was positively related to diastolic blood pressure [6.58 (1.57 to 11.58)] and inversely with moderate-to-vigorous physical activity [- 69.30 (- 134.92 to - 3.70)]. Distance to a shopping center (1600 m) was positively related to body mass index [4.78 (1.11 to 8.45)] and shopping center (1000 m) was positively related to systolic blood pressure respectively [76.99 (0.03 to 83.95)].

CONCLUSION

Distance to community and shopping centers were significantly associated with BMI, systolic, diastolic blood pressure and moderate-to-vigorous physical activity. Future research should include multiple aspects of built environment variables in order to provide for a broader understanding of their effect on cardiovascular risk profile of African populations.

Successful and unsuccessful weight-loss maintainers: strategies to counteract metabolic compensation following weight loss

Adaptive thermogenesis and reduced fat oxidative capacity may accompany weight loss, continuing in weight maintenance. The present study aimed (1) to determine whether weight-reduced and weight-loss relapsed women are at greater metabolic risk for weight gain compared with BMI-matched controls with no weight-loss history, and (2) to identify protective strategies that might attenuate weight loss-associated adaptive thermogenesis and support successful weight-loss maintenance. Four groups of women were recruited: reduced-overweight/obese (RED, n 15), controls (low-weight stable weight; LSW, n 19) BMI <27 kg/m²; relapsed-overweight/obese (REL, n 11), controls (overweight/obese stable weight; OSW, n 11) BMI >27 kg/m². Body composition (bioelectrical impedance), 75 g oral glucose tolerance test, fasting and postprandial metabolic rate (MR) and substrate utilisation (RER) and physical activity (accelerometer (7 d)) were measured. Sociobehavioural questionnaires and 3 × 24 h diet recalls were completed. Fasting and postprandial MR, RER and total daily energy intake (TDEI) were not different between RED and REL v. controls (P > 0·05). RED consumed less carbohydrate (44·8 (sd 10·3) v. 53·4 (sd 10·0) % TDEI, P = 0·020), more protein (19·2 (sd 6·0) v. 15·6 (sd 4·2) % TDEI, P = 0·049) and increased physical activity, but behaviourally reported greater dietary restraint (P = 0·002) compared with controls. TDEI, macronutrient intake and physical activity were similar between OSW and REL. REL reported higher subjective fasting and lower postprandial ratings of prospective food consumption compared with OSW. Weight-reduced women had similar RMR (adjusted for fat-free mass) compared with controls with no weight-loss history. Increased physical activity, higher protein intake and greater lean muscle mass may have counteracted weight loss-associated metabolic compensation and highlights their importance in weight-maintenance programmes.

Predicting the Future Need of Walking Device or Assistance by Moderate to Vigorous Physical Activity: A 2-Year Prospective Study of Women Aged 75 Years and Above

Objective

To examine the association between daily moderate to vigorous physical activity (MVPA) and the change in mobility function among community-dwelling Japanese women aged 75 years and above.

Methods

This prospective study included 330 older women aged 75 years and above who could walk without a walking device or assistance. MVPA and light-intensity physical activity (LPA) were assessed using an accelerometer for seven consecutive days. MVPA was defined as an activity with an intensity of >3 metabolic equivalents. The study outcome was a change in mobility function, defined as the need of walking device or assistance, during the two-year period.

Results

The results of the logistic regression analysis showed that MVPA was inversely associated with a decline in mobility function after controlling for LPA and potential confounders (adjusted odds ratio (OR) = 0.93 per 1 min/d, 95% confidence interval (CI) = 0.88-0.99; P = 0.017), whereas LPA was not when adjusted for MVPA and confounders (adjusted OR = 0.99 per 1 min/d, 95% CI = 0.96-1.01; P = 0.245). The receiver operating characteristics analysis identified a 7.9 min/d of MVPA as the cut-off value.

Conclusions

The results of this study suggest the importance of promoting daily MVPA for preventing mobility limitation in older women aged 75 years and above.

Pattern of Daily Steps is Associated with Weight Loss: Secondary Analysis from the Step-Up Randomized Trial

OBJECTIVE

The aim of this study was to examine the association between the amount, intensity, and pattern of steps·day^-1 with weight loss.

METHODS

Participants (N = 260; age = 42.8 ± 8.9 y; BMI = 32.8 ± 3.5 kg/m² ) completed an 18-month weight-loss intervention that included a calorie-restricted diet and prescribed physical activity. Participants were categorized by 18-month weight loss as weight gain (GAIN), weight loss of 0% to < 5% (WL < 5%), 5% to < 10% (WL < 10%), or ≥ 10% (WL ≥ 10%). Steps·day^-1 were measured at 0, 6, 12, and 18 months and defined as total steps·day^-1 , total steps·day^-1 of moderate-to-vigorous physical activity (MVPA) (≥3 metabolic equivalents) in bouts of ≥ 10 minutes (BOUT-MVPA), MVPA in bouts of < 10 minutes (NON-BOUT-MVPA), or non-MVPA steps·day^-1 (NON-MVPA).

RESULTS

There was a weight-loss category by time interaction (P < 0.0001) for total and BOUT-MVPA steps·day^-1 . The total steps·day^-1 at 18 months were WL ≥ 10% = 9,822 (95% CI: 9,073-10,571), WL < 10% = 8,612 (7,613-9,610), WL < 5% = 7,802 (6,782-8,822), and GAIN = 7,801 (6,549-9,053). BOUT-MVPA steps·day^-1 at 18 months were WL ≥ 10% = 3,482 (2,982-3,981), WL < 10% = 1,949 (1,269-2,629), WL < 5% = 1,735 (1,045-2,426), and GAIN = 1,075 (210-1,941). Participants were also categorized based on achieving ≥ 10% weight loss at either 6 or 18 months, and a similar pattern was observed.

CONCLUSIONS

These findings show that 10,000 steps·day^-1 , with approximately 3,500 steps·day^-1 performed as BOUT-MVPA, are associated with enhanced weight loss in a behavioral intervention.

Classification and Processing of 24-Hour Wrist Accelerometer Data

Background: An important step in accelerometer data analysis is the classification of continuous, 24-hour data into sleep, wake, and non-wear time. We compared classification times and physical activity metrics across different data processing and classification methods.Methods: Participants (n = 576) from the Finnish Retirement and Aging Study (FIREA) wore an accelerometer on their non-dominant wrist for seven days and nights and filled in daily logs with sleep and waking times. Accelerometer data were first classified as sleep or wake time by log, and Tudor-Locke, Tracy, and ActiGraph algorithms. Then, wake periods were classified as wear or non-wear by log, Choi algorithm, and wear sensor. We compared time classification (sleep, wake, and wake wear time) as well as physical activity measures (total activity volume and sedentary time) across these classification methods.Results:M(SD) nightly sleep time was 467 (49) minutes by log and 419 (88), 522 (86), and 453 (74) minutes by Tudor-Locke, Tracy, and ActiGraph algorithms, respectively. Wake wear time did not differ substantially when comparing Choi algorithm and the log. The wear sensor did not work properly in about 29% of the participants. Daily sedentary time varied by 8–81 minutes after excluding sleep by different methods and by 1–18 minutes after excluding non-wear time by different methods. Total activity volume did not substantially differ across the methods.Conclusion: The differences in wear and sedentary time were larger than differences in total activity volume. Methods for defining sleep periods had larger impact on outcomes than methods for defining wear time.

Changes in Weight, Sedentary Behaviour and Physical Activity during the School Year and Summer Vacation

Background: To examine bidirectional associations between body weight and objectively assessed sedentary behaviour (SB) and physical activity (PA) during the school year and summer vacation. Methods: Participants were 209 Japanese boys and girls (9.0 ± 1.8 years at baseline). SB and PA were measured using triaxial accelerometry that discriminated between ambulatory and non-ambulatory PA, screen time measured by questionnaire during the school-term was evaluated in May and the summer vacation, and relative body weight measured in May and just after the end of summer vacation. Results: There were no significant relationships between changes in SB or PA and changes in body weight. However, higher relative body weight at baseline was associated with decreased non-ambulatory moderate PA (p = 0.049), but this association was slightly diminished after adjusting for change in SB (p = 0.056). Longer screen time at baseline was also associated with increased relative body weight (p = 0.033). Conclusions: The present study revealed that body weight might be particularly influential on non-ambulatory moderate PA while SB, PA or changes in these variables did not predict changes in body weight. Moreover, screen time during the school year is a predictor of change in relative body weight during the subsequent summer vacation.

Interactions between individual and perceived environmental factors on Latinas' physical activity

Background

Latinas have disproportionately low levels of physical activity (PA) and the ecological correlates of their PA remain unclear. This study aims to test interactions between individual and environmental factors on Latinas' PA.

Methods

We analyzed baseline data from 436 Latinas participating in a PA randomized controlled trial in San Diego, CA [Fe en Acción/Faith in Action]. Measures included demographics, perceived environment, PA and anthropometrics. Mixed effects models examined interactions between individual and environmental factors on self-reported leisure-time and transportation, and accelerometer-assessed PA.

Results

Significant positive associations were found between neighborhood aesthetics and leisure-time moderate-to-vigorous PA (MVPA) and between having destinations within walking distance from home and transportation PA (P < 0.05). We found significant interactions of income with aesthetics and sidewalk maintenance as well as between weight status and safety from crime. Favorable aesthetics was related to more leisure-time MVPA only among lower income women (odds ratio (OR) = 1.57; 95% confidence interval (CI): 1.18, 2.08); however, higher income women reporting better sidewalk maintenance reported more leisure-time MVPA (OR = 1.51; 95% CI: 1.06, 2.15). Higher perceived safety from crime was positively related to transportation PA only among overweight/obese women.

Conclusions

Subgroup differences should be considered when developing interventions targeting the neighborhood environment to promote Latinas' PA.

Defining Accelerometer Nonwear Time to Maximize Detection of Sedentary Time in Youth

PURPOSE

The present study examined various accelerometer nonwear definitions and their impact on detection of sedentary time using different ActiGraph models, filters, and axes.

METHODS

In total, 61 youth (34 children and 27 adolescents; aged 5-17 y) wore a 7164 and GT3X+ ActiGraph on a hip-worn belt during a 90-minute structured sedentary activity. Data from GT3X+ were downloaded using the Normal filter (N) and low-frequency extension (LFE), and vertical axis (V) and vector magnitude (VM) counts were examined. Nine nonwear definitions were applied to the 7164 model (V), GT3X+LFE (V and VM), and GT3X+N (V and VM), and sedentary estimates were computed.

RESULTS

The GT3X+LFE-VM was most sensitive to movement and could accurately detect observed sedentary time with the shortest nonwear definition of 20 minutes of consecutive "0" counts for children and 40 minutes for adolescents. The GT3X+N-V was least sensitive to movement and required longer definitions to detect observed sedentary time (40 min for children and 90 min for adolescents). VM definitions were 10 minutes shorter than V definitions. LFE definitions were 40 minutes shorter than N definitions in adolescents.

CONCLUSION

Different nonwear definitions are needed for children and adolescents and for different model-filter-axis types. Authors need to consider nonwear definitions when comparing prevalence rates of sedentary behavior across studies.

Variability and reliability study of overall physical activity and activity intensity levels using 24 h-accelerometry-assessed data

Background

24 h-accelerometry is now used to objectively assess physical activity (PA) in many observational studies like the German National Cohort; however, PA variability, observational time needed to estimate habitual PA, and reliability are unclear.

Methods

We assessed 24 h-PA of 50 participants using triaxial accelerometers (ActiGraph GT3X+) over 2 weeks. Variability of overall PA and different PA intensities (time in inactivity and in low intensity, moderate, vigorous, and very vigorous PA) between days of assessment or days of the week was quantified using linear mixed-effects and random effects models. We calculated the required number of days to estimate PA, and calculated PA reliability using intraclass correlation coefficients.

Results

Between- and within-person variance accounted for 34.4–45.5% and 54.5–65.6%, respectively, of total variance in overall PA and PA intensities over the 2 weeks. Overall PA and times in low intensity, moderate, and vigorous PA decreased slightly over the first 3 days of assessment. Overall PA (p = 0.03), time in inactivity (p = 0.003), in low intensity PA (p = 0.001), in moderate PA (p = 0.02), and in vigorous PA (p = 0.04) slightly differed between days of the week, being highest on Wednesday and Friday and lowest on Sunday and Monday, with apparent differences between Saturday and Sunday. In nested random models, the day of the week accounted for < 19% of total variance in the PA parameters. On average, the required number of days to estimate habitual PA was around 1 week, being 7 for overall PA and ranging from 6 to 9 for the PA intensities. Week-to-week reliability was good (intraclass correlation coefficients, range, 0.68–0.82).

Conclusions

Individual PA, as assessed using 24 h-accelerometry, is highly variable between days, but the day of assessment or the day of the week explain only small parts of this variance. Our data indicate that 1 week of assessment is necessary for reliable estimation of habitual PA.

Electronic supplementary material

The online version of this article (10.1186/s12889-018-5415-8) contains supplementary material, which is available to authorized users.

Impact of different recruitment strategies on accelerometry adherence and resulting physical activity data: A secondary analysis

Strategies for increasing adherence to physical activity assessments are often linked to extra financial or personal effort. This paper aims to investigate the influence of the recruitment strategy on participants' adherence to accelerometry and resulting PA data. Data were used from two previous studies conducted in 2013 and 2016 in Cologne, Germany, differing in recruitment strategy (N = 103, 40.8% male, mean age 20.9 ± 3.7 years, mean BMI 23.7 ± 4.1 kg/m²). In the passive recruitment (PR) group, vocational students took part in the accelerometry (ActiGraph GT3X+) in line with the main study unless they denied participation. In the active recruitment (AR) group, vocational students were invited to actively volunteer for the accelerometry. Impact of recruitment strategy on adherence and PA data was examined by regression analysis. Average adherence to the accelerometry was 66.7% (AR) and 74.0% (PR). No statistically significant influence of recruitment strategy on adherence and resulting PA was found (all p > 0.05). The difference in recruitment strategy did not affect adherence to accelerometry. The data imply that AR may be applicable. Future studies using larger sample sizes and diverse populations should further investigate these trends.

•

Active and passive volunteer recruitment strategy for accelerometry are presented.

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Active volunteer recruitment for accelerometry does not increase adherence.

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Active and passive volunteer recruitment do not differ in objective physical activity.

•

Active volunteer recruitment is applicable in large sample sizes.

Strategies for Dealing with Missing Accelerometer Data

Missing data is a universal research problem that can affect studies examining the relationship between physical activity measured with accelerometers and health outcomes. Statistical techniques are available to deal with missing data; however, available techniques have not been synthesized. A scoping review was conducted to summarize the advantages and disadvantages of identified methods of dealing with missing data from accelerometers. Missing data poses a threat to the validity and interpretation of trials using physical activity data from accelerometry. Imputation using multiple imputation techniques is recommended to deal with missing data and improve the validity and interpretation of studies using accelerometry.

Weight management in rural health clinics: The Midwest diet and exercise trial

Obesity prevalence is higher in rural compared to urban residents. Rural health clinics offer a potential venue for delivery of weight management. However, traditional programs require travel to attend on-site meetings which is impractical or inconvenient for rural residents. Clinic staff in most rural settings are unlikely to be trained to provide effective weight management. Remote delivery using group phone conferences (GP) or individual phone calls (IP), by staff associated with rural clinics eliminates the need for travel to attend on-site meetings. The effectiveness of these approaches will be the focus of this trial. Staff at five primary care clinics, serving primarily rural residents, will be trained to deliver GP and IP interventions and an enhanced usual care (EUC), (i.e., individual face-to-face meetings (~45 min) at clinic site, four times across 18 mos.). Two hundred overweight/obese adults (BMI ≥ 25.0-45.0 kg/m², age ≥ 21 yrs.) will be recruited through each clinic and randomized to GP (n = 80), IP (n = 80), or EUC (n = 40) to compare weight loss (0-6 mos.), weight maintenance (7-18 mos.), and weight change during a 6 mo. no contact follow-up (19-24 mos.) between intervention arms. The GP and IP interventions will be identical in lesson plan content, diet, and physical activity. The only difference between groups will be the delivery format (group vs. individual) and session duration (GP ~45 min/session; IP ~15 min/session). Primary (body weight) and secondary outcomes (waist circumference, energy/macronutrient intake, physical activity) will be assessed at baseline, 6, 12, 18 and 24 mos. Cost and contingent valuation analyses will also be completed.

NCT REGISTRATION

NCT02932748.

Monitoring Walker Assistive Devices: A Novel Approach Based on Load Cells and Optical Distance Measurements

This paper presents a measurement system intended to monitor the usage of walker assistive devices. The goal is to guide the user in the correct use of the device in order to prevent risky situations and maximize comfort. Two risk indicators are defined: one related to force unbalance and the other related to motor incoordination. Force unbalance is measured by load cells attached to the walker legs, while motor incoordination is estimated by synchronizing force measurements with distance data provided by an optical sensor. The measurement system is equipped with a Bluetooth link that enables local supervision on a computer or tablet. Calibration and experimental results are included in the paper.

Correlates of intensity-specific physical activity in children aged 9-11 years: a multilevel analysis of UK data from the International Study of Childhood Obesity, Lifestyle and the Environment

OBJECTIVES

Physical activity (PA) can provide numerous physical and psychological health gains, yet a low proportion of children in England are sufficiently active to accrue benefit. Analysing the correlates of PA from a socioecological perspective may help to identify factors that promote versus discourage PA. The purpose of the present study was to: (1) assess the relationships between a wide range of potential correlates and intensity-specific PA and (2) explore which correlates are associated with meeting government PA guidelines.

DESIGN, SETTING AND PARTICIPANTS

Cross-sectional study on children aged 9-11 years from the South West of England (n=425; 183 males).

OUTCOME MEASURES

A mixture of self-reported and objective measures (eg, body mass index (BMI), accelerometer-derived PA, self-reported sport participation, etc) were collected from child participants, parents and school teachers. After adjusting for covariates (ie, age, sex and accelerometer wear time), multilevel modelling techniques were employed to examine the relationships between potential correlates and light-intensity, moderate-intensity and vigorous-intensity PA, as measured with an ActiGraph GT3X+ accelerometer. Generalised linear mixed modelling was used to analyse the correlates associated with government-recommended levels of PA.

RESULTS

Computer use shared a negative association whereas parent support for PA showed a positive relationship with light-intensity PA. In terms of moderate-intensity PA, computer use and BMI z-score shared a negative association whereas positive relationships were found for sport participation, active transport and for outdoor time after school. Children at schools with 25%-49% of pupils attending school sport/PA clubs did more moderate-intensity PA than those attending schools with lower participation rates. For vigorous-intensity PA, a negative relationship was observed for BMI z-score, and positive associations for self-efficacy, active transport, parent support and the presence of crossing guards on routes to school. Correlates associated with meeting the PA guidelines were BMI z-score (negative), sport participation, active transport and outdoor time after school (all positive).

CONCLUSION

Results demonstrate that factors pertaining to the individual, home and school environment may play an important role in understanding the correlates of differing PA intensities in children.

TRIAL REGISTRATION NUMBER

NCT01722500.

Correlates of intensity-specific physical activity in children aged 9-11 years: a multilevel analysis of UK data from the International Study of Childhood Obesity, Lifestyle and the Environment

OBJECTIVES

Physical activity (PA) can provide numerous physical and psychological health gains, yet a low proportion of children in England are sufficiently active to accrue benefit. Analysing the correlates of PA from a socioecological perspective may help to identify factors that promote versus discourage PA. The purpose of the present study was to: (1) assess the relationships between a wide range of potential correlates and intensity-specific PA and (2) explore which correlates are associated with meeting government PA guidelines.

DESIGN, SETTING AND PARTICIPANTS

Cross-sectional study on children aged 9-11 years from the South West of England (n=425; 183 males).

OUTCOME MEASURES

A mixture of self-reported and objective measures (eg, body mass index (BMI), accelerometer-derived PA, self-reported sport participation, etc) were collected from child participants, parents and school teachers. After adjusting for covariates (ie, age, sex and accelerometer wear time), multilevel modelling techniques were employed to examine the relationships between potential correlates and light-intensity, moderate-intensity and vigorous-intensity PA, as measured with an ActiGraph GT3X+ accelerometer. Generalised linear mixed modelling was used to analyse the correlates associated with government-recommended levels of PA.

RESULTS

Computer use shared a negative association whereas parent support for PA showed a positive relationship with light-intensity PA. In terms of moderate-intensity PA, computer use and BMI z-score shared a negative association whereas positive relationships were found for sport participation, active transport and for outdoor time after school. Children at schools with 25%-49% of pupils attending school sport/PA clubs did more moderate-intensity PA than those attending schools with lower participation rates. For vigorous-intensity PA, a negative relationship was observed for BMI z-score, and positive associations for self-efficacy, active transport, parent support and the presence of crossing guards on routes to school. Correlates associated with meeting the PA guidelines were BMI z-score (negative), sport participation, active transport and outdoor time after school (all positive).

CONCLUSION

Results demonstrate that factors pertaining to the individual, home and school environment may play an important role in understanding the correlates of differing PA intensities in children.

TRIAL REGISTRATION NUMBER

NCT01722500.

Validity of Combination Use of Activity Record and Accelerometry to Measure Free-Living Total Energy Expenditure in Female Endurance Runners

Yoshida, A, Ishikawa-Takata, K, Tanaka, S, Suzuki, N, Nakae, S, Murata, H, Taguchi, M, and Higuchi, M. Validity of combination use of activity record and accelerometry to measure free-living total energy expenditure in female endurance runners. J Strength Cond Res 33(11): 2962-2970, 2019-Herein, we attempted to prove the validity of a new approach to assessing total energy expenditure (TEE) that combines activity recording and accelerometry in athletes. Eight female endurance runners participated in this study. We measured TEE over 8 days in the regular training season by using the doubly labeled water (DLW) method. In the combined method, an activity record of the rating of perceived exertion (RPE) was used to estimate energy expenditure (EE) during the training period, whereas a triaxial accelerometer was used to evaluate EE during the nontraining time over the TEE measurement period using the DLW method. Training EE was calculated from the subjects' individual rating of perceived exertion-EE correlations provided by the exercise tolerance test. Resting metabolic rate (RMR) was measured using indirect calorimetry. There were no significant differences in TEE, activity-induced EE (AEE), or physical activity level (PAL; TEE/RMR) between the DLW method and the combined method (TEE, 3,032 ± 344 vs. 3,033 ± 495 kcal·d; AEE, 1,585 ± 303 vs. 1,586 ± 442 kcal·d; and PAL, 2.68 ± 0.37 vs. 2.68 ± 0.48, respectively). Significant positive correlations and no systematic errors were observed in AEE and PAL. Intraclass correlation coefficients were high (TEE, 0.785; AEE, 0.841; and PAL, 0.779, respectively). These findings suggest that the combined method has high validity against the DLW method. Thus, the combined method would be able to estimate free-living TEE in the regular training season for female endurance runners.

The number of repeated observations needed to estimate the habitual physical activity of an individual to a given level of precision

Physical activity behavior varies naturally from day to day, from week to week and even across seasons. In order to assess the habitual level of physical activity of a person, the person must be monitored for long enough so that the level can be identified, taking into account this natural within-person variation. An important question, and one whose answer has implications for study- and survey design, epidemiological research and population surveillance, is, for how long does an individual need to be monitored before such a habitual level or pattern can be identified to a desired level of precision? The aim of this study was to estimate the number of repeated observations needed to identify the habitual physical activity behaviour of an individual to a given degree of precision. A convenience sample of 50 Swedish adults wore accelerometers during four consecutive weeks. The number of days needed to come within 5–50% of an individual's usual physical activity 95% of the time was calculated. To get an idea of the uncertainty of the estimates all statistical estimates were bootstrapped 2000 times. The mean number of days of measurement needed for the observation to, with 95% confidence, be within 20% of the habitual physical activity of an individual is highest for vigorous physical activity, for which 182 days are needed. For sedentary behaviour the equivalent number of days is 2.4. To capture 80% of the sample to within ±20% of their habitual level of physical activity, 3.4 days is needed if sedentary behavior is the outcome of interest, and 34.8 days for MVPA. The present study shows that for analyses requiring accurate data at the individual level a longer measurement collection period than the traditional 7-day protocol should be used. In addition, the amount of MVPA was negatively associated with the number of days required to identify the habitual physical activity level indicating that the least active are also those whose habitual physical activity level is the most difficult to identify. These results could have important implications for researchers whose aim is to analyse data on an individual level. Before recommendations regarding an appropriate monitoring protocol are updated, the present study should be replicated in different populations.

Effects of a Weight Loss Program on Metabolic Syndrome, Eating Disorders and Psychological Outcomes: Mediation by Endocannabinoids?

OBJECTIVE

To evaluate the effects of weight loss on endocannabinoids, cardiometabolic and psychological parameters, eating disorders (ED) as well as quality of life (QoL) and to elucidate the role of endocannabinoids in metabolic syndrome (MS).

METHODS

In total, 114 patients with obesity were prospectively included in a 12-month weight loss program. Plasma endocannabinoids were measured by mass spectrometry; ED, psychological and QoL-related parameters were evaluated by self-reported questionnaires; physical activity was measured by accelerometer. Nutritional assessment was done by a 3-day food diary.

RESULTS

Among completers (n = 87), body weight decreased in 35 patients (-9.1 ± 8.6 kg), remained stable in 39 patients, and increased in 13 patients (+5.8 ± 3.4 kg). 75% of patients with MS at baseline were free of MS at follow-up, and their baseline plasma N-palmitoylethanolamide (PEA) values were significantly lower when compared to patients with persisting MS. At baseline, there was a positive relationship between PEA and waist circumference (p = 0.005, R2 = 0.08), fasting glucose (p < 0.0001, R2 = 0.12), total cholesterol (p = 0.001, R2 = 0.11), triglycerides (p = 0.001, R2 = 0.11), LDL-cholesterol (p = 0.03, R2 = 0.05) as well as depression score (p = 0.002, R2 = 0.29).

CONCLUSION

Plasma PEA might play a role in metabolic improvement after weight loss. Even in subjects without weight loss, a multidisciplinary intervention improves psychological outcomes, ED, and QoL.

Late breast cancer treatment-related symptoms and functioning: associations with physical activity adoption and maintenance during a lifestyle intervention for rural survivors

PURPOSE

Physical activity may be difficult for survivors with poorer functioning following primary treatment. The study examined whether late symptoms of breast cancer treatment impact PA adoption (0-6 months) and maintenance (6-18 months) during a weight management intervention, and whether late symptoms influence PA when accounting for overall functioning.

METHODS

Secondary analyses were conducted using a sample of survivors participating in a weight management intervention and who provided valid weight and accelerometer data at baseline and 6 months (N = 176). The Breast Cancer Prevention Trial Symptom Checklist (BCPT) assessed late treatment-related symptoms. SF-12 Physical Component Scale (PCS) and Mental Component Scale (MCS) scores assessed functioning.

RESULTS

Change in bouted moderate to vigorous physical activity (MVPA) min/week from baseline to 6 months was not associated with BCPT scales (all p values > 0.05). When adding SF-12 scores to the model, change in bouted MVPA min/week was significantly associated with the PCS (p = 0.045). Change in MVPA min/week from 6 to 18 months was significantly associated with cognitive symptoms (p = 0.004), but not musculoskeletal or vasomotor symptoms (p values > 0.05). When adding 6-month SF-12 scores to the model, MVPA min/week was significantly associated with PCS (p = 0.001) and MCS (p = 0.028); however, BCPT cognitive problems score became non-significant (p > 0.05).

CONCLUSIONS

Poorer physical functioning was associated with lower PA adoption, and poorer mental and physical functioning was associated with lower maintenance of PA, while late symptoms generally were not. Interventionists should consider level of functioning when identifying individual PA goals during weight management interventions.

Amount, Distribution, and Quality of Protein Intake Are Not Associated with Muscle Mass, Strength, and Power in Healthy Older Adults without Functional Limitations-An enable Study

To maintain muscle mass in older age, several aspects regarding the amount and distribution of protein intake have been suggested. Our objective was to investigate single and combined associations of daily protein intake, evenness of protein distribution across the three main meals, number of meals providing ≥0.4 g protein/kg body weight (BW), and number of meals providing ≥2.5 g leucine, with muscle mass, strength, and power in successful agers. In this cross-sectional study in 97 healthy community-dwelling adults without functional limitations aged 75-85 years, protein intake was assessed using 7-day food records. Muscle mass, leg muscle strength, leg muscle power, and handgrip strength were measured according to standardized protocols. Mean daily protein intake was 0.97 ± 0.28 g/kg BW and the coefficient of variance between main meals was 0.53 ± 0.19. Per day, 0.72 ± 0.50 meals providing ≥0.4 g protein/kg BW and 1.11 ± 0.76 meals providing ≥2.5 g leucine were consumed. No correlations between single or combined aspects of protein intake and skeletal muscle index, leg muscle power, leg muscle strength, or handgrip strength were observed (Spearman's r of -0.280 to 0.291). In this sample of healthy older adults without functional limitations, aspects of protein intake were not associated with muscle mass, strength, or power.

Ease of walking associates with greater free-living physical activity and reduced depressive symptomology in breast cancer survivors: pilot randomized trial

PURPOSE

We hypothesized exercise training-induced improvements in ease of walking would associate with favorable changes in objectively measured physical activity (PA) and self-reported depressive symptoms following a PA behavior-change intervention in non-metastatic breast cancer survivors (BCS).

METHODS

Twenty-seven BCS received random assignment to an intervention (INT) or control group (CON). INT included counseling/group discussions coupled with supervised exercise tapered to unsupervised exercise. PA, depressive symptoms, and ease of walking were evaluated pre-/post-intervention using 10-day accelerometry, HADS depression subscale, and indirect calorimetry during a standardized treadmill test, respectively. PA composite score was calculated by converting weekly minutes of moderate-to-vigorous PA and average steps/day to z-scores then dividing the sum by 2. Cardiac efficiency was determined by dividing steady-state oxygen uptake by heart rate to evaluate the volume of oxygen consumed per heartbeat.

RESULTS

ANCOVA revealed a significant time by group interaction showing the INT group exhibited greater positive changes in the PA composite compared to the CON (INT, + 0.14 ± 0.66 au vs. CON, - 0.48 ± 0.49 au; p = 0.019; η _p² = 0.21). Changes occurring from baseline to follow-up, among all participants, revealed improved ease of walking (less oxygen uptake) associated with increased PA composite (r = - 0.52; p = 0.010) and lower depressive symptomology (r = 0.50; p = 0.012) adjusted for age, race, and months since cancer diagnosis. Increased cardiac efficiency during the standardized treadmill test also associated with less daily sedentary time (r = - 0.52; p = 0.021).

CONCLUSIONS

These data support the assertion that reducing the physiological difficulty of walking may contribute to greater engagement in free-living PA, less sedentary time, and decreased psychosocial distress among BCS.

Accelerometer-determined peak cadence and weight status in children from São Caetano do Sul, Brazil

The purpose of this study was to determine the relationship between peak cadence indicators and body mass index (BMI) and body fat percentage (BF%)-defined weight status in children. The sample comprised 485 Brazilian children. Minute-by-minute step data from accelerometry were rank ordered for each day to identify the peak 1-minute, 30-minute and 60-minute cadence values. Data were described by BMI-defined and bioelectrical impedance-determined BF% weight status. BMI-defined normal weight children had higher peak 1-minute (115.5 versus 110.6 and 106.6 steps/min), 30-minute (81.0 versus 77.5 and 74.0 steps/min) and 60-minute cadence (67.1 versus 63.4 and 60.7 steps/min) than overweight and obese children (p<.0001), respectively. Defined using %BF, normal weight children had higher peak 1-minute (114.5 versus 106.1 steps/min), 30-minute (80.4 versus 73.1 steps/min) and 60-minute cadence (66.5 versus 59.9 steps/min) than obese children (p<.0001). Similar relationships were observed in boys; however, only peak 1- minute cadence differed significantly across BMI and %BF-defined weight status categories in girls. Peak cadence indicators were negatively associated with BMI and BF% in these schoolchildren and significantly higher among normal weight compared to overweight or obese children.

Differences in Behavior, Time, Location, and Built Environment between Objectively Measured Utilitarian and Recreational Walking

OBJECTIVES

Utilitarian and recreational walking both contribute to physical activity. Yet walking for these two purposes may be different behaviors. We sought to provide operational definitions of utilitarian and recreational walking and to objectively measure their behavioral, spatial, and temporal differences in order to inform transportation and public health policies and interventions.

METHODS

Data were collected 2008-2009 from 651 Seattle-King County residents, wearing an accelerometer and a GPS unit, and filling-in a travel diary for 7 days. Walking activity bouts were classified as utilitarian or recreational based on whether walking had a destination or not. Differences between the two walking purposes were analyzed, adjusting for the nested structure of walking activity within participants.

RESULTS

Of the 4,905 observed walking bouts, 87.4% were utilitarian and 12.6% recreational walking. Utilitarian walking bouts were 45% shorter in duration (-12.1 min) and 9% faster in speed (+0.3km/h) than recreational walking bouts. Recreational walking occurred more frequently in the home neighborhood and was not associated with recreational land uses. Utilitarian walking occurred in areas having higher residential, employment, and street density, lower residential property value, higher area percentage of mixed-use neighborhood destinations, lower percentage of parks/trails, and lower average topographic slope than recreational walking.

CONCLUSION

Utilitarian and recreational walking are substantially different in terms of frequency, speed, duration, location, and related built environment. Policies that promote walking should adopt type-specific strategies. The high occurrence of recreational walking near home highlights the importance of the home neighborhood for this activity.

Patterns and Levels of Sedentary Behavior and Physical Activity in a General Japanese Population: The Hisayama Study

Background

The purpose of this cross-sectional study was to describe the patterns and levels of sedentary time and physical activity (PA) in a general Japanese population.

Methods

A total of 1,740 community-dwelling Japanese adults aged ≥40 years participated in this study. Sedentary time and PA were assessed for 7 consecutive days using a tri-axial accelerometer. Daily patterns and levels of sedentary time and PA were calculated by sex, age group (40–64, 65–74, and ≥75 years), and body mass index (BMI; <25 and ≥25 kg/m²).

Results

Participants spent half of their waking time being sedentary, 32.7% of which was accumulated in prolonged bouts ≥30 minutes, versus only 54.4 minutes/day (7% of waking time) as moderate-to-vigorous PA (MVPA) (11.8 minutes/day in bouts ≥10 minutes). In addition to total sedentary time, men had longer prolonged sedentary bouts and fewer breaks per sedentary hour than women. Similar trends were observed in participants aged ≥75 years and those with a higher BMI (≥25 kg/m²) compared to those with a younger age and lower BMI. Moreover, participants aged ≥75 years and those with a higher BMI accumulated fewer MVPA minutes in bouts ≥10 minutes. Only 34.8% of the population met the recommended level of ≥150 minutes/week MVPA in bouts ≥10 minutes.

Conclusion

Japanese adults accumulated a large proportion of total sedentary time in prolonged bouts but few minutes in sustained bouts of MVPA, and few of them met the current PA guideline.

Comparison of Measures of Maximal and Submaximal Fitness in Response to Exercise

INTRODUCTION

Adoption of physical activity (PA) consistent with current guidelines does not improve maximal cardiorespiratory fitness (mCRF; V˙O2peak) beyond the error of measurement for approximately 30% of adults. Whether PA improves measures of exercise tolerance at submaximal levels (submaximal cardiorespiratory fitness [sCRF]) independent of change in mCRF is unknown. Here we assessed the relationship between exercise-induced changes in mCRF and sCRF.

METHODS

Twenty-five physically inactive men 30-60 yrs old (mean ± SD = 44.3 ± 9.1 yr) completed 4 wk of supervised exercise consisting of 30 min of exercise, five times per week at 65% mCRF. mCRF was assessed using a maximal treadmill test. sCRF was measured as follows: 1) exercise tolerance, the distance traveled during a 12-min time trial on a treadmill, and 2) change in heart rate (HR) at submaximal work rates during the maximal treadmill test. Daily PA was measured by accelerometry at baseline and 4 wk.

RESULTS

mCRF (P = 0.009) and both measures of sCRF (P < 0.001) improved at 4 wk. No change in measures of daily PA was observed at 4-wk compared with baseline (P > 0.05). No association was observed between exercise-induced change in mCRF and change in either measure of sCRF (P > 0.05) after exercise training. In the group of participants who did not improve mCRF beyond the measurement error (n = 13, or 52%), we observed a significant improvement in both measures of sCRF (P < 0.001). Among these 13 individuals, all improved in at least one measure of sCRF.

CONCLUSION

Exercise-induced improvements in mCRF were not associated with improvements in either measure of sCRF. Improvements in submaximal measures of cardiorespiratory fitness are observed in the absence of change in mCRF. Measures of sCRF capture peripheral adaptations to exercise not captured by measures of mCRF alone.

Accelerometric estimates of physical activity vary unstably with data handling

Background

Because of unreliable self-report, accelerometry is increasingly used to objectively monitor physical activity (PA). However, results of accelerometric studies vary depending on the chosen cutpoints between activity intensities. Population-specific activity patterns likely affect the size of these differences. To establish their size and stability we apply three sets of cutpoints, including two calibrated to a single reference, to our accelerometric data and compare PA estimates.

Methods

1402 German adolescents from the GINIplus and LISAplus cohorts wore triaxial accelerometers (Actigraph GT3x) for one week (mean 6.23 days, 14.7 hours per day) at the hip. After validation of wear, we applied three sets of cutpoints for youth, including the most common standard (Freedson, 2005) and two calibrated to a single reference, (Romanzini uni- and triaxial, from Romanzini, 2014) to these data, estimating daily sedentary, light, moderate, vigorous and moderate-to-vigorous PA (MPA, VPA, MVPA). Stability of differences was assessed by comparing Romanzini’s two sets of cutpoints.

Results

Relative agreement between cutpoints was closer for activity of lower intensities (largest difference for sedentary behaviour 9%) but increased for higher intensities (largest difference for light activity 40%, MPA 102%, VPA 88%; all p<0.01). Romanzini’s uniaxial and triaxial cutpoints agreed no more closely with each other than with Freedson’s.

Conclusions

Estimated PA differed significantly between different sets of cutpoints, even when those cutpoints agreed perfectly on another dataset (i.e. Romanzini’s.) This suggests that the detected differences in estimated PA depend on population-specific activity patterns, which cannot be easily corrected for: converting activity estimates from one set of cutpoints to another may require access to raw data. This limits the utility of accelerometry for comparing populations in place and time. We suggest that accelerometric research adopt a standard for data processing, and apply and present the results of this standard in addition to those from any other method.

Validity of proximity sensor-based wear-time detection using the ActiGraph GT9X

Our study investigated the performance of proximity sensor-based wear-time detection using the GT9X under laboratory and free-living settings. Fifty-two volunteers (23.2 ± 3.8 y; 23.2 ± 3.7 kg/m²) participated in either a laboratory or free-living protocol. Lab participants wore and removed a wrist-worn GT9X on 3-5 occasions during a 3-hour directly observed activity protocol. The 2-day free-living protocol used an independent temperature sensor and self-report as the reference to determine if wrist and hip-worn GT9X accurately determined wear (i.e., sensitivity) and non-wear (i.e., specificity). Free-living estimates of wear/non-wear were also compared to Troiano 2007 and Choi 2012 wear/non-wear algorithms. In lab, sensitivity and specificity of the wrist-worn GT9X in detecting total minutes of wear-on and off was 93% and 49%, respectively. The GT9X detected wear-off more often than wear-on, but with a greater margin of error (4.8 ± 11.6 vs. 1.4 ± 1.4 min). In the free-living protocol, wrist and hip-worn GT9X's yielded sensitivity and specificity of 72 and 90% and 84 and 92%, respectively. GT9X estimations had inferior sensitivity but superior specificity to Troiano 2007 and Choi 2012 algorithms. Due to inaccuracies, it may not be advisable to singularly use the proximity-sensor-based wear-time detection method to detect wear-time.

Change in Physical Activity During a Weight Management Intervention for Breast Cancer Survivors: Association with Weight Outcomes

OBJECTIVE

This study examined the effects of a group phone-based weight management intervention on change in physical activity as measured via accelerometer and self-report in rural breast cancer survivors. The study also evaluated the role of physical activity on clinically meaningful cut points for weight loss (baseline to 6 months) and weight loss maintenance (6 to 18 months).

METHODS

Participants were breast cancer survivors in a weight management intervention who provided valid weight and accelerometer data (N = 142). Participants were categorized into four groups based on weight loss ≥10% and weight regain ≥5% at 18 months.

RESULTS

Accelerometer-measured moderate-to-vigorous physical activity (MVPA) significantly increased from baseline to 6 months (+46.9 minutes). MVPA declined during maintenance but remained significantly greater than baseline. Self-reported MVPA followed a similar pattern as accelerometer MVPA, but estimates were significantly higher. Participants in the high loss, low regain group had significantly higher MVPA at all points.

CONCLUSIONS

A distance-based weight management intervention for survivors improved physical activity outcomes over 18 months. Self-reported physical activity was substantially higher than accelerometer measured. Findings highlight the importance of device-based measurement for characterizing the magnitude of physical activity change as well as the role of physical activity in weight management outcomes.

Physical activity after outpatient surgery and enhanced recovery for total knee arthroplasty

PURPOSE AND HYPOTHESIS

The purpose of this study was to 'objectively' measure improvement of physical activity with the use of an activity monitor between patients who followed an enhanced recovery- or outpatient surgery pathway after total knee arthroplasty (TKA). It was hypothesized that both pathways will have comparable physical activity after TKA at 6-week follow-up.

METHODS

This prospective observational comparative case study was designed to investigate activity parameters (e.g. physical activity, number of steps, sit-stand transfers) of two different pathways after 6 weeks with the use of a non-invasive triaxial accelerometer activity monitor. This study included 20 patients with a mean age of 65.5 years (SD 6.1) undergoing TKA who were allocated to follow one of the two pathways: enhanced recovery (n = 10) or outpatient surgery (n = 10). Patients were monitored for 4 days pre-, 4 days during and 4 days after 5 weeks postoperatively. Patient-reported outcome measures (PROMs) and range of knee motion were obtained pre- and 6 weeks postoperatively.

RESULTS

The activity parameters recovered steeply during the first 4 postoperative days and continued to improve within both pathways (n.s.). Preoperative and during the first 4 days and 5 weeks postoperative, activity parameters were comparable (n.s.) between both pathways but did not reach preoperative levels of physical activity and range of motion (n.s.). PROMs improved within each pathway, and no difference between both pathways was observed (n.s.).

CONCLUSIONS

This study demonstrates that the early physical activity parameters of patients after TKA, following the outpatient surgery pathway, were similar to patients who followed the standard enhanced recovery pathway. The activity monitor is an added value for a more detailed and objective analysis of the physical performance in patients after TKA.

LEVEL OF EVIDENCE

III.

Increased Walking's Additive and No Substitution Effect on Total Physical Activity

PURPOSE

We assessed the associations between a change in time spent walking and a change in total physical activity (PA) time within an urban living adult sample to test for additive or substitution effects.

METHODS

Participants living in the greater Seattle area were assessed in 2008-2009 and again 1-2 yr later (2010-2011). At each time point, they wore accelerometers and GPS units and recorded trips and locations in a travel diary for seven consecutive days. These data streams were combined to derive a more objective estimate of walking and total PA. Participants also completed the International Physical Activity Questionnaire to provide self-reported estimates of walking and total PA. Regression analyses assessed the associations between within-participant changes in objective and self-reported walking and total PA.

RESULTS

Data came from 437 participants. On average, a 1-min increase in total walking was associated with an increase in total PA of 1 min, measured by objective data, and 1.2-min, measured by self-reported data. A similar additive effect was consistently found with utilitarian, transportation, or job-related walking, measured by both objective and self-reported data. For recreational walking, the effect of change was mixed between objective and self-reported results.

CONCLUSION

Both objective and self-reported data confirmed an additive effect of utilitarian and total walking on PA.

Physical activity in outpatients with mental disorders: status, measurement and social cognitive determinants of health behavior change

INTRODUCTION

Physical activity (PA) can play an important role in improving the mental and physical health in patients with mental disorders but is not well studied in this population. The aim of this study was to assess the status of PA in outpatients with mental disorders, compare the convergence of self-rating and accelerometer measurement and examine the influence of social cognitive variables from the Motivation-Volition (MoVo) model and clinical measures on PA.

METHODS

Eighty-four patients were recruited from three psychiatric outpatient clinics and local psychiatrists (Distribution of ICD-10-Diagnoses: F3.x = 59.5%, F4.x = 20.2%, F2.x = 17.9%, F1.x = 2.4%). PA, Self-efficacy, Outcome-expectancies, Intention, Self-concordance, Action- and Coping-planning, Health-related Quality of Life (SF-12) and Psychiatric Symptoms (SCL-27) were assessed through questionnaires. PA was assessed objectively by accelerometers.

RESULTS

Most of the participants did not reach PA recommendations. Subjective and objective measurement of PA showed good accordance for total PA on group level but lower accordance on individual level. Motivational and volitional determinants of health behavior change showed a similar pattern of correlations with PA as in populations without mental disorders.

CONCLUSION

Outpatients with mental disorders have the ability and are willing to perform PA but a large proportion of our sample did not meet PA recommendations. To assess group levels of PA, subjective and objective measurement seem equally apt, for individual diagnostics, a combination of both should be considered. Social cognitive determinants of health behavior change seem to be as helpful for the design of PA interventions for patients with mental disorders as they are in other populations.

The Impact of Low Accelerometer Wear Time on the Estimates and Application of Sedentary Behavior and Physical Activity Data in Adults

BACKGROUND

This investigation sought to determine how accelerometer wear (1) biased estimates of sedentary behavior (SB) and physical activity (PA), (2) affected misclassifications for meeting the Physical Activity Guidelines for Americans, and (3) impacted the results of regression models examining the association between moderate to vigorous physical activity (MVPA) and a clinically relevant health outcome.

METHODS

A total of 100 participants [age: 20.6 (7.9) y] wore an ActiGraph GT3X+ accelerometer for 15.9 (1.6) hours per day (reference dataset) on the hip. The BOD POD was used to determine body fat percentage. A data removal technique was applied to the reference dataset to create individual datasets with wear time ranging from 15 to 10 hours per day for SB and each intensity of PA.

RESULTS

Underestimations of SB and each intensity of PA increased as accelerometer wear time decreased by up to 167.2 minutes per day. These underestimations resulted in Physical Activity Guidelines for Americans misclassification rates of up to 42.9%. The regression models for the association between MVPA and body fat percentage demonstrated changes in the estimates for each wear-time adherence level when compared to the model using the reference MVPA data.

CONCLUSIONS

Increasing accelerometer wear improves daily estimates of SB and PA, thereby also improving the precision of statistical inferences that are made from accelerometer data.

Relationships between sleep duration, physical activity and body mass index in young New Zealanders: An isotemporal substitution analysis

BACKGROUND

The evidence regarding the unique effect of sedentary behaviour on obesity among children is unclear. Moreover, the effect of substituting sedentary behaviour with physical activity of different intensities on the body composition of children has received limited empirical study.

OBJECTIVE

To examine the mathematical effects on Body Mass Index (BMI) of substituting sedentary behaviours with physical activities of different intensities on children and youth aged 5-14 years old in New Zealand.

METHODS

Secondary analysis of accelerometer data from the National Survey of Children and Young People's Physical Activity and Dietary Behaviours in New Zealand (2008/09) was conducted. A total of 1812 children and youth aged 5-24 years provided accelerometer-derived data on daily sedentary time (SB), light intensity physical activity (LPA) and moderate to vigorous physical activity (MVPA). Sleep time was assessed with a validated computerised use-of-time tool. BMI was assessed using anthropometric measurements. Multiple linear regression models were used to examine the independent associations of SB, Sleep time, LPA, and MVPA on BMI. The isotemporal substitution approach was used to ascertain the mathematical effect of substituting each of the other behaviours on BMI. Analyses were stratified by age groups.

RESULTS

SB showed a unique (inverse) association with BMI across all age groups (p<0.05) but 20-24 years (p>0.05). Similarly, MVPA was positively associated (p<0.001) across all age groups. Among age groups 5-9 years, 10-14 years and 15-19 years, the estimated impact of replacing 60 min/day of SB with the same amount of MVPA time resulted in decreased BMI for all age groups (p<0.001), ranging from -1.26 (5-9 years) to -1.43 units (15-19 years). Similar results were achieved when SB was replaced with LPA or sleeping time for children (5-19 years). In young people (age group 20-24), the impact of replacing 30 min/day of SB with MVPA resulted in an estimated -1 BMI units decrease (p<0.001).

CONCLUSION

MVPA and SB have a unique effect on BMI. Further, substituting SB with LPA or MVPA was associated with a favourable effect on BMI across all age groups; with MVPA having the strongest association.

Promise of Wearable Physical Activity Monitors in Oncology Practice

Commercially available physical activity monitors provide clinicians an opportunity to obtain oncology patient health measures to an unprecedented degree. These devices can provide objective and quantifiable measures of physical activity, which are not subject to errors or bias of self-reporting or shorter duration of formal testing. Prior work on so-called quantified-self data was based on older-generation, research-grade accelerometers, which laid the foundation for consumer-based physical activity monitoring devices to be validated as a feasible and reliable tool in patients with cancer. Physical activity monitors are being used in chronic conditions including chronic obstructive pulmonary disease, congestive heart failure, diabetes mellitus, and obesity. Differing demographics, compounded with higher symptom and treatment burdens in patients with cancer, imply that additional work is needed to understand the unique strengths and weaknesses of physical activity monitors in this population. Oncology programs can systematically implement these tools into their workflows in an adaptable and iterative manner. Translating large amounts of data collected from an individual physical activity monitoring device into clinically relevant information requires sophisticated data compilation and reduction. In this article, we summarize the characteristics of older- and newer-generation physical activity monitors, review the validation of physical activity monitors with respect to health-related quality-of-life assessments, and describe the current role of these devices for the practicing oncologist. We also highlight the challenges and next steps needed for physical activity monitors to provide relevant information that can change the current state of oncology practice.

The Effect of Changes in Physical Activity on Sedentary Behavior: Results From a Randomized Lifestyle Intervention Trial

PURPOSE

To investigate whether changes in physical activity (PA) have an impact on sedentary behavior (SB) during a lifestyle intervention.

DESIGN

Study design was a randomized trial.

SETTING/SUBJECTS

Participants (n = 204) were individuals with low PA and high sedentary leisure screen time from the Chicago area.

INTERVENTION

Participants were randomized to either increase PA (iPA) or decrease sedentary leisure (dSED). The intervention consisted of decision support, coaching, and financial incentives. For iPA participants, the goal was at least 60 min/d of self-reported moderate-tovigorous-intensity PA (MVPA). For dSED participants the goal was less than 90 min/d of sedentary leisure screen time.

MEASURES

Daily accelerometer-based measures of SB and bout-corrected MVPA were obtained.

ANALYSIS

Linear mixed-effects models were fit to estimate the effect of the intervention on MVPA and total SB and to estimate the effect of daily changes in MVPA on daily SB.

RESULTS

The iPA participants increased their bout-corrected MVPA by 14 min/d (p < .001) and decreased their total SB by 18 min/d (p < .001). The dSED participants did not significantly change their PA or their total SB. On days when participants exercised, each 10-minute bout of MVPA was associated with a 6-minute decrease in SB on the same day (p < .001).

CONCLUSION

In an intervention study designed to increase MVPA, participants who increase their time spent exercising will obtain much of this time by reducing their SB.

Enhanced insulin sensitivity in successful, long-term weight loss maintainers compared with matched controls with no weight loss history

Background:

Weight gain is associated with deterioration in metabolic health, whereas weight loss improves insulin sensitivity. This study assesses the impact of long-term, successfully maintained weight loss and weight-loss relapse on measures of insulin sensitivity and identifies factors that explain variability in insulin sensitivity.

Methods:

Women (20–45 years) were recruited into four groups: reduced-overweight/obese (RED, n=15); body mass index (BMI)-matched controls (stable low-weight, n=19), BMI⩽27 kg m⁻²; relapsed-overweight/obese subjects (REL, n=11); and BMI-matched controls (obese stable weight, n=11), BMI⩾27 kg m⁻². A 75 g oral glucose tolerance test determined fasting and 2 h plasma glucose and insulin. Homeostatic Model Assessment (HOMA-IR) and insulin sensitivity index (ISI_(0,120)) assessed insulin sensitivity. Anthropometric measurements, fasting resting metabolic rate (RMR) and respiratory quotient (RQ) were measured. Questionnaires and dietary intake were recorded, and physical activity was measured using accelerometers.

Results:

RED were more insulin sensitive, characterised by lower fasting (P=0.001) and 2 h insulin (P=0.003) levels compared with all other groups. There were no significant differences in dietary intake, sedentary, light and moderate activity, RMR or RQ in the RED compared with the other three groups. % Body weight (BW) lost (P<0.001), % BW regained (P<0.05), body fat %, light activity (P<0.05, only log HOMA), vigorous activity (P<0.05) and RQ (P<0.01) predicted 61.4% and 59.7% of variability in log HOMA and log ISI_(0,120), respectively, in multiple linear regression models.

Conclusion:

This study showed sustained enhanced insulin sensitivity in successful weight loss maintainers compared with BMI-matched controls with no weight loss history. Weight-loss-relapsed individuals were indistinguishable from controls. Weight loss itself was the strongest predictor of improved insulin sensitivity, whereas weight regain significantly predicted reduced insulin sensitivity. Weight-loss maintenance programs are essential to retaining metabolic benefits acquired through weight loss. Being physically active, reducing sedentary behaviour and, in particular, including small amounts of vigorous physical activity significantly predicted improved insulin sensitivity.

Integrated Social- and Neurocognitive Model of Physical Activity Behavior in Older Adults with Metabolic Disease

BACKGROUND

Despite the proven benefits of physical activity to treat and prevent metabolic diseases, such as diabetes (T2D) and metabolic syndrome (MetS), most individuals with metabolic disease do not meet physical activity (PA) recommendations. PA is a complex behavior requiring substantial motivational and cognitive resources. The purpose of this study was to examine social cognitive and neuropsychological determinants of PA behavior in older adults with T2D and MetS. The hypothesized model theorized that baseline self-regulatory strategy use and cognitive function would indirectly influence PA through self-efficacy.

METHODS

Older adults with T2D or MetS (M age = 61.8 ± 6.4) completed either an 8-week physical activity intervention (n = 58) or an online metabolic health education course (n = 58) and a follow-up at 6 months. Measures included cognitive function, self-efficacy, self-regulatory strategy use, and PA.

RESULTS

The data partially supported the hypothesized model (χ2 = 158.535(131), p > .05, comparative fit index = .96, root mean square error of approximation = .04, standardized root mean square residual = .06) with self-regulatory strategy use directly predicting self-efficacy (β = .33, p < .05), which in turn predicted PA (β = .21, p < .05). Performance on various cognitive function tasks predicted PA directly and indirectly via self-efficacy. Baseline physical activity (β = .62, p < .01) and intervention group assignment via self-efficacy (β = -.20, p < .05) predicted follow-up PA. The model accounted for 54.4 % of the variance in PA at month 6.

CONCLUSIONS

Findings partially support the hypothesized model and indicate that select cognitive functions (i.e., working memory, inhibition, attention, and task-switching) predicted PA behavior 6 months later. Future research warrants the development of interventions targeting cognitive function, self-regulatory skill development, and self-efficacy enhancement.

TRIAL REGISTRATION NUMBER

The trial was registered with the clinical trial number NCT01790724.

Methodological considerations and impact of school-based interventions on objectively measured physical activity in adolescents: a systematic review and meta-analysis

OBJECTIVE

The aims of this systematic review and meta-analysis are (i) to determine the impact of school-based interventions on objectively measured physical activity among adolescents and (ii) to examine accelerometer methods and decision rule reporting in previous interventions.

METHODS

A systematic search was performed to identify randomized controlled trials targeting adolescents (age: ≥10 years), conducted in the school setting, and reporting objectively measured physical activity. Random effects meta-analyses were conducted to determine the pooled effects of previous interventions on total and moderate-to-vigorous physical activity. Potential moderators of intervention effects were also explored.

RESULTS

Thirteen articles met the inclusion criteria, and twelve were included in the meta-analysis. The pooled effects were small and non-significant for both total physical activity (standardized mean difference = 0.02 [95% confidence interval = -0.13 to 0.18]) and moderate-to-vigorous physical activity (standardized mean difference = 0.24 [95% confidence interval = -0.08 to 0.56]). Sample age and accelerometer compliance were significant moderators for total physical activity, with a younger sample and higher compliance associated with larger effects.

CONCLUSION

Previous school-based physical activity interventions targeting adolescents have been largely unsuccessful, particularly for older adolescents. There is a need for more high-quality research using objective monitoring in this population. Future interventions should comply with best-practice recommendations regarding physical activity monitoring protocols.

Comparison between logbook-reported and objectively-assessed physical activity and sedentary time in breast cancer patients: an agreement study

Background

Increasing physical activity (PA) and decreasing sedentary time (ST) have important health effects among breast cancer patients, a growing population group. PA and sedentary behaviors are complex multi-dimensional behaviors and are challenging to monitor accurately. To date few studies have compared self-reports and objective measurement in assessing PA and ST in women undergoing breast cancer treatments. The aim of the present study was to compare self-reports and objective measures for assessing daily time spent in moderate-intensity physical activity (MPA), vigorous-intensity physical activity (VPA) and ST in women undergoing breast cancer treatments.

Methods

Baseline data from 65 women with breast cancer scheduled to undergo adjuvant treatment was included. Daily time spent in MPA, VPA and ST was assessed by a study-specific logbook and the SenseWear Armband mini (SWA). The level of agreement between the two measurement methods was then determined by performing Bland-Altman plots with limits of agreements, and calculating Spearman’s rank correlation coefficients.

Results

The mean difference between the logbook and SWA with limits of agreement was 14 (±102) minutes for MPA, 1 (±21) minute for VPA and −196 (±408) minutes for ST, respectively. The logbook reported an average of 34 and 50% higher values than the SWA for MPA and VPA, as well as an average of 27% lower values for ST (P < 0.05). The Spearman’s rank correlation coefficients showed that the differences between the methods increased as the average amount of time spent in PA and ST increased (P < 0.01).

Conclusions

The results imply that the two measurement methods have limited agreement and cannot be used interchangeably.

Physical activity, sedentary behavior and their correlates in children with Autism Spectrum Disorder: A systematic review

Autism Spectrum Disorder affects up to 2.5% of children and is associated with harmful health outcomes (e.g. obesity). Low levels of physical activity and high levels of sedentary behaviors may contribute to harmful health outcomes. To systematically review the prevalence and correlates of physical activity and sedentary behaviors in children with Autism Spectrum Disorder, electronic databases (PsycINFO, SPORTDiscus, EMBASE, Medline) were searched from inception to November 2015. The review was registered with PROSPERO (CRD42014013849). Peer-reviewed, English language studies were included. Two reviewers screened potentially relevant articles. Outcomes of interest were physical activity and sedentary behaviour levels and their potential correlates. Data were collected and analysed in 2015. Of 35 included studies, 15 reported physical activity prevalence, 10 reported physical activity correlates, 18 reported sedentary behavior prevalence, and 10 reported sedentary behavior correlates. Estimates of children’s physical activity (34–166 mins/day, average 86 mins/day) and sedentary behavior (126–558 mins/day in screen time, average 271 mins/day; 428–750 mins/day in total sedentary behavior, average 479 mins/day) varied across studies. Age was consistently inversely associated, and sex inconsistently associated with physical activity. Age and sex were inconsistently associated with sedentary behavior. Sample sizes were small. All but one of the studies were classified as having high risk of bias. Few correlates have been reported in sufficient studies to provide overall estimates of associations. Potential correlates in the physical environment remain largely unexamined. This review highlights varying levels of physical activity and sedentary behavior in children with Autism Spectrum Disorder. Research is needed to consistently identify the correlates of these behaviors. There is a critical need for interventions to support healthy levels of these behaviors.

The Use of Functional Data Analysis to Evaluate Activity in a Spontaneous Model of Degenerative Joint Disease Associated Pain in Cats

Introduction and objectives

Accelerometry is used as an objective measure of physical activity in humans and veterinary species. In cats, one important use of accelerometry is in the study of therapeutics designed to treat degenerative joint disease (DJD) associated pain, where it serves as the most widely applied objective outcome measure. These analyses have commonly used summary measures, calculating the mean activity per-minute over days and comparing between treatment periods. While this technique has been effective, information about the pattern of activity in cats is lost. In this study, functional data analysis was applied to activity data from client-owned cats with (n = 83) and without (n = 15) DJD. Functional data analysis retains information about the pattern of activity over the 24-hour day, providing insight into activity over time. We hypothesized that 1) cats without DJD would have higher activity counts and intensity of activity than cats with DJD; 2) that activity counts and intensity of activity in cats with DJD would be inversely correlated with total radiographic DJD burden and total orthopedic pain score; and 3) that activity counts and intensity would have a different pattern on weekends versus weekdays.

Results and conclusions

Results showed marked inter-cat variability in activity. Cats exhibited a bimodal pattern of activity with a sharp peak in the morning and broader peak in the evening. Results further showed that this pattern was different on weekends than weekdays, with the morning peak being shifted to the right (later). Cats with DJD showed different patterns of activity from cats without DJD, though activity and intensity were not always lower; instead both the peaks and troughs of activity were less extreme than those of the cats without DJD. Functional data analysis provides insight into the pattern of activity in cats, and an alternative method for analyzing accelerometry data that incorporates fluctuations in activity across the day.

Patterns of Sedentary Behavior in US Middle-Age and Older Adults: The REGARDS Study

PURPOSE

The purposes of this study were to examine patterns of objectively measured sedentary behavior in a national cohort of US middle-age and older adults and to determine factors that influence prolonged sedentary behavior.

METHODS

We studied 8096 participants from the REasons for Geographic and Racial Differences in Stroke (REGARDS) Study, a population-based study of black and white adults 45 yr or older. Seven-day accelerometry was conducted. Prolonged sedentary behavior was defined as accumulating 50% or more of total sedentary time in bouts of 30 min or greater.

RESULTS

The number of sedentary bouts greater than or equal to 20, 30, 60, and 90 min were 8.8 ± 2.3, 5.5 ± 1.9, 1.9 ± 1.1, and 0.8 ± 0.7 bouts per day, respectively. Sedentary bouts greater than or equal to 20, 30, 60, and 90 min accounted for 60.0% ± 13.9%, 48.0% ± 15.5%, 26.0% ± 15.4%, and 14.2% ± 12.9% of total sedentary time, respectively. Several factors were associated with prolonged sedentary behavior in multivariate-adjusted models (odds ratio [95% confidence interval]): older age (65-74 yr: 1.99 [1.55-2.57]; 75 yr or older: 4.68 [3.61-6.07] vs 45-54 yr), male sex (1.41 [1.28-1.56] vs female), residence in nonstroke belt/buckle region of the United States (stroke belt: 0.87 [0.77-0.98]; stroke buckle: 0.86 [0.77-0.95] vs non-belt/buckle), body mass index (BMI) (overweight: 1.33 [1.18-1.51]; obese: 2.15 [1.89-2.44] vs normal weight), winter (1.18 [1.03-1.35] vs summer), and low amounts of moderate-to-vigorous physical activity (MVPA) [0 min·wk: 2.00 [1.66-2.40] vs ≥150 min·wk).

CONCLUSIONS

In this sample of US middle-age and older adults, a large proportion of total sedentary time was accumulated in prolonged, uninterrupted bouts of sedentary behavior as almost one-half was accumulated in sedentary bouts greater than or equal to 30 min. Several sociodemographic (age, sex, and BMI), behavioral (MVPA), environmental (region), and seasonal factors are associated with patterns of prolonged sedentary behavior.

Objectively Measured Physical Activity and Mortality Risk Among American Adults

INTRODUCTION

One major limitation of prior studies examining the influence of physical activity on mortality is use of self-reported measures. This study examined the association between objectively measured light physical activity (LPA) and moderate to vigorous physical activity (MVPA) and all-cause mortality.

METHODS

This study included 5,562 adults from the 2003-2006 National Health and Nutrition Examination Survey. LPA and MVPA were measured over 4-7 days using Actigraph AM-7164 accelerometers. For both activity intensities, the first quintile defined low participation and the remaining quintiles defined modest to high participation. Information on age, sex, race, SES, diet, smoking, and alcohol were collected and controlled for. Survival status through December 31, 2011, was determined. Average follow-up was 6.7 years. Data were analyzed in 2015.

RESULTS

In women, the all-cause mortality hazard ratio (HR) was 0.58 (95% CI=0.38, 0.88) for modest to high LPA and 0.34 (95% CI=0.20, 0.57) for modest to high MVPA. Corresponding HRs in men were 1.02 (95% CI=0.64, 1.61) and 0.39 (95% CI=0.27, 0.56). Compared with women with a low LPA/low MVPA combination, mortality risk was reduced in the modest to high LPA/low MVPA (HR=0.42, 95% CI=0.26, 0.70), low LPA/modest to high MVPA (HR=0.16, 95% CI=0.07, 0.34), and modest to high LPA/modest to high MVPA (HR=0.17, 95% CI=0.09, 0.36) combinations. In men, mortality risk was not reduced with modest to high LPA/low MVPA.

CONCLUSIONS

MVPA was associated with a substantially lower mortality risk. LPA was associated with lower mortality risk, but only within women with low MVPA.

Daily Physical Activity Patterns During the Early Stage of Alzheimer's Disease

BACKGROUND

Alzheimer's disease (AD) is a neurodegenerative disease that results in severe disability. Very few studies have explored changes in daily physical activity patterns during early stages of AD when components of physical function and mobility may be preserved.

OBJECTIVE

Our study explored differences in daily physical activity profiles, independent of the effects of non-cognitive factors including physical function and age, among individuals with mild AD compared to controls.

METHODS

Patients with mild AD and controls (n = 92) recruited from the University of Kansas Alzheimer's Disease Center Registry, wore the Actigraph GT3X+ for seven days, and provided objective physical function (VO2 max) and mobility data. Using multivariate linear regression, we explored whether individuals with mild AD had different daily average and diurnal physical activity patterns compared to controls independent of non-cognitive factors that may affect physical activity, including physical function and mobility.

RESULTS

We found that mild AD was associated with less moderate-intensity physical activity (p < 0.05), lower peak activity (p < 0.01), and lower physical activity complexity (p < 0.05) particularly during the morning. Mild AD was not associated with greater sedentary activity or less lower-intensity physical activity across the day after adjusting for non-cognitive covariates.

CONCLUSIONS

These findings suggest that factors independent of physical capacity and mobility may drive declines in moderate-intensity physical activity, and not lower-intensity or sedentary activity, during the early stage of AD. This underscores the importance of a better mechanistic understanding of how cognitive decline and AD pathology impact physical activity. Findings emphasize the potential value of designing and testing time-of-day specific physical activity interventions targeting individuals in the early stages of AD, prior to significant declines in mobility and physical function.