RT3 Accelerometer Research Articles

Association of accelerometer-measured physical activity and its change with progression to chronic kidney disease in adults with type 2 diabetes and overweight/obesity

ObjectiveTo examine the long-term association of objectively measured moderate-to-vigorous physical activity (MVPA) and its longitudinal changes with progression to chronic kidney disease (CKD) in patients with type 2 diabetes (T2D)...

170-OR: Association of Timing of Physical Activity Bouts with Cardiorespiratory Fitness in Adults with Type 2 Diabetes in the Look AHEAD Study

Background: Moderate-to-vigorous physical activity (MVPA) is an important treatment in type 2 diabetes (T2D). Few studies examine the timing of MVPA, as there are no established methods to characterize the MVPA bout timing throughout the day. We determined the timing of MVPA bouts in adults with T2D, and examined whether cardiorespiratory fitness and odds of cardiovascular disease (CVD) history relate to timing of MVPA bouts in men and women. Methods: Baseline data from Look AHEAD participants (n=2153, 57% women) were analyzed. Cardiorespiratory fitness assessed by VO2max test was expressed as METs. MVPA bouts (≥3METs in ≥10mins bouts) were determined using the hip-worn RT3 accelerometer for 7 days. Participants were categorized into six groups based on the time of day with the major amount of MVPA bouts (MET-min): ≥50% of MVPA bouts during the same time window (Early morning, Late morning, Afternoon, or Evening, N=214-280/group), <50% of MVPA bouts in any time category (Mixed; reference group, N=436), and ≤1 day with MVPA bouts per week (Inactive, N=624). Results: Cardiorespiratory fitness differed by timing of MVPA bout category (P<0.0001). In a multivariate adjusted model, the association of timing of MVPA bouts with fitness varied by sex (P=0.002). In women, the evening group had higher fitness (β 0.35 [0.04, 0.66] METs). After further adjustment for individual total bout-MVPA (MET-min) per week, in men, the early morning group was associated with higher fitness (β 0.46 [0.06, 0.85] METs). Interestingly, in men, but not in women, the early morning group also had higher odds of CVD history (OR 2.4 [1.38, 4.21]). Conclusion: Higher cardiorespiratory fitness associated with evening MVPA bouts in women, and with early morning MVPA bouts in men independent of total amount of bout-MVPA. Prospective studies are needed to investigate the relationship between timing of MVPA and cardiovascular outcomes to optimize MVPA benefits in adults with T2D. Disclosure J. Qian: None. M.P. Walkup: None. S. Chen: None. P.H. Brubaker: None. D. Bond: None. P.A. Richey: None. J.M. Jakicic: Advisory Panel; Self; Weight Watchers International, Inc. K. Hu: None. F.A. Scheer: None. R. Middelbeek: None.

Association Between Objectively Measured Physical Activity and Opioid, Hypnotic, or Anticholinergic Medication Use in Older People: Data from the Physical Activity Cohort Scotland Study

Centrally acting medications cause cognitive slowing and incoordination, which could reduce older people's physical activity levels. This association has not been studied previously. The aim of this study was to examine the association between opioid, hypnotic and anticholinergic medication, and objectively measured physical activity, in a cohort of older people. We used data from the Physical Activity Cohort Scotland, a representative cohort of community-dwelling older people aged 65years and over who were assessed at baseline and again 2-3years later. Objective physical activity was measured using Stayhealthy RT3 accelerometers over 7days. Baseline medication use (opioid use, hypnotic use, modified Anticholinergic Risk Scale [mARS]) was obtained from linked, routinely collected community prescribing records. Cross-sectional and longitudinal associations between baseline medication use and both baseline activity and change in activity over time were analysed using unadjusted and adjusted linear regression models. Overall, 310 participants were included in the analysis; mean age 77years (standard deviation 7). No association was seen between baseline use of any medication class and baseline physical activity levels in unadjusted or adjusted models. For change in activity over time, there was no difference between users and non-users of hypnotics or opioids. Higher anticholinergic burden was associated with a steeper decline in activity over the follow-up period (mARS 0: -7051counts/24h/year; mARS1-2: -15,942counts/24h/year; mARS ≥ 3: -19,544counts/24h/year; p = 0.03) and this remained robust to multiple adjustments. Anticholinergic burden is associated with greater decline in objectively measured physical activity over time in older people, a finding not seen with hypnotic or opioid use.

Do adults with Down syndrome do the same amount of physical activity as adults without disability? A proof of principle study.

This study compared levels of physical activity completed by adults with and without Down syndrome. Fifteen adults with and 15 adults without Down syndrome matched for age and gender, took part. The intensity and duration of physical activity were measured using RT3 accelerometers worn for seven days. Only, 12 participants with Down syndrome had complete physical activity data, and these participants and their matched controls (total: six females, 18 males; aged 25.8±9.7) were included in the analyses. There were significantly lower levels of moderate and vigorous physical activity per day for people with Down syndrome (median=27min) compared to those without (median=101min) (p<.001). Participants without disability were twice more likely to achieve recommended levels of physical activity than people with Down syndrome. Adults with Down syndrome appear to participate in lower levels of physical activity than adults without Down syndrome. Further research should validate these estimates.

Factors associated with change in objectively measured physical activity in older people \u2013 data from the physical activity cohort Scotland study

BackgroundCross-sectional relationships between physical activity and health have been explored extensively, but less is known about how physical activity changes with time in older people. The aim of this study was to assess baseline predictors of how objectively measured physical activity changes with time in older people.MethodsLongitudinal cohort study using data from the Physical Activity Cohort Scotland. A sample of community-dwelling older people aged 65 and over were recruited in 2009–2011, then followed up 2–3 years later. Physical activity was measured using Stayhealthy RT3 accelerometers over 7 days. Other data collected included baseline comorbidity, health-related quality of life (SF-36), extended Theory of Planned Behaviour Questionnaire and Social Capital Module of the General Household Survey. Associations between follow-up accelerometer counts and baseline predictors were analysed using a series of linear regression models, adjusting for baseline activity levels and follow-up time.ResultsFollow up data were available for 339 of the original 584 participants. The mean age was 77 years, 185 (55%) were female and mean follow up time was 26 months. Mean activity counts fell by between 2% per year (age < =80, deprivation decile 5–10) and 12% per year (age > 80, deprivation decile 5–10) from baseline values. In univariate analysis age, sex, deprivation decile, most SF-36 domains, most measures of social connectedness, most measures from the extended Theory of Planned Behaviour, hypertension, diabetes mellitus, chronic pain and depression score were significantly associated with adjusted activity counts at follow-up. In multivariate regression age, satisfactory friend network, SF-36 physical function score, and the presence of diabetes mellitus were independent predictors of activity counts at follow up after adjustment for baseline count and duration of follow up.ConclusionsHealth status and social connectedness, but not extended Theory of Planned Behaviour measures, independently predicted changes in physical activity in community dwelling older people.

Reduced fitness and physical functioning are long-term sequelae after curative treatment for esophageal cancer: a matched control study.

Reduced physical functioning is common following resections for esophageal cancer; however, objective data on physical performance outcomes in this cohort are rare. The aim of this study was to assess the physical performance and health related quality of life (HRQOL) of disease free survivors and compare findings in a case matched noncancer control group. Twenty-five males (mean (±SD) aged 63 (±6) years) who were over 6 months postesophagectomy and disease-free were compared with 25 controls (60 ± 6 years). Physical functioning was assessed through hand grip strength (dynamometry), exercise capacity (incremental shuttle walk test), physical activity levels (RT3 accelerometer), and body composition (bio-electrical impedance analysis). Health-related quality of life was measured using the EORTC QLQ-C30 questionnaire. Esophageal cancer survivors demonstrated significantly lower fitness (P < 0.001) and time spent in moderate (P < 0.001) and vigorous (P < 0.001) intensity physical activity compared with controls. Global health status and quality of life were similar in both groups (P = 0.245); however, physical and role functioning domains were lower in the cancer survivors (P < 0.001, and P = 0.001, respectively). These data show that disease-free survivors of curative esophageal cancer treatment demonstrate a significant compromise in physical functioning compared with controls, thus highlighting the multiple, complex rehabilitative needs of this cohort.

An investigation into the daily level of voluntary activity of stabled riding school horses

The importance of correct feeding practice has been highlighted by the increasing prevalence of obesity in horses. Human research has suggested that voluntary activity (VA) levels may influence digestible energy (DE) requirements, accounting for 15-50% of human daily energy expenditure. Therefore, the aim of this study was to investigate whether levels of non-structured exercise differed between stabled horses with similar bodyweight (BW) and similar structured workloads, but with different estimated DE intakes to maintain their BW. Twelve mature horses were selected based on their estimated DE intake and BW, and were paired according to their BW, breed, estimated DE intake, and structured exercise. Within each pair, one horse (L) was fed a relatively lower estimated DE intake than the other horse (H) to maintain a similar, constant BW and performing similar levels of structured exercise. Estimated DE intake was therefore significantly (P&lt;0.01) different between Group L and Group H. Each pair was observed for 72 h during which structured exercise and non-structured exercise were measured. Heart rate was used as a measure of workload during the structured exercise. Two RT3 accelerometers, located on a roller (RT3-R) and head collar (RT3-H), were used to measure VA levels when stabled in addition to visual observations using focal sampling between 07:00 and 18:00 h. RT3-R and RT3-H activity levels were not significantly (P&gt;0.05) different between individual horses. Median activity counts were significantly (P≤0.001) higher during the day time (06:30-18:29 h) compared to the night time (18:30-06:29 h). However, measured activity using RT3 accelerometers did not show a significant difference between horses in Group L and Group H (P&gt;0.05). It was therefore concluded, that differences in VA levels during stabling could not explain the difference in estimated DE requirements between horses with a similar BW and workload.

Validation of the AX3 triaxial accelerometer in older functionally impaired people

BackgroundStudying physical activity (PA) trends in older populations and potential interventions for increasing PA is important, as PA is a factor in many age-related health outcomes such as chronic disease, premature mortality, physical function and injuries from falls. Objective measures of PA provide valuable information regarding the functional impact that ageing and chronic disease states may have on a patient’s life.AimsThe purpose of this study was to test the validity of the AX3 PA monitor in an older population and to investigate whether the AX3 is a valid measure of distinct types or levels of activity in older people with a spectrum of mobility.MethodsValidity of the AX3 PA monitor was tested using the RT3 as a means of cross-validating the AX3. Study participants wore both the AX3 and the RT3 accelerometers, positioned on their non-dominant side, whilst completing a series of standardised everyday activities.ResultsAlthough overall correlation was high (r > 0.8) between the RT3 and lower-limb-mounted AX3 counts, the correlation between the two devices was much stronger for walking activity than for any of the non-walking activities.DiscussionActivity counts at all lower limb positions for the AX3 and RT3 were highly correlated. Correlation between wrist-mounted AX3 counts and lower limb AX3 counts was only moderate, and worsened when walking aids were in use.ConclusionsThe results of this study indicate that the AX3 monitor is a valid tool, which might be used to objectively measure walking activity in older functionally impaired adults, a welcome finding for this under-researched area.

Physical Activity, Physical Fitness and Overweight in Early Schoolchildren

Purpose: The aim of this study was to evaluate physical activity and physical fitness levels in children 7-8 years old with different body mass index (BMI). Methods: Eighty nine children (age 7.6 ± 0.4) participated in this study. BMI was used as obesity indicator and children were categorized in normal-weight and overweight/obese groups. Daily physical activity was assessed by RT3 accelerometer (Stayhealthy Inc, Monrovia, CA) and physical fitness was assessed using the European physical fitness test battery (Eurofit). Results: Analysis of variance (ANOVA) indicated no significant differences in the average daily total counts of physical activity and in scores of four fitness tests between the overweight/obese and normal-weight group (p>0.05). However, boys were significantly more physically active than girls (p<0.05) and the level of physical activity was higher on weekdays than on weekend for both BMI groups (p<0.05). Conclusion: The results indicate that physical activity is not the main contributing factor for childhood overweight at this age. Sufficient levels of daily physical activity were also shown to lead in good physical performance.

Development of an accelerometer-linked online intervention system to promote physical activity in adolescents.

Most adolescents do not achieve the recommended levels of moderate-to-vigorous physical activity (MVPA), placing them at increased risk for a diverse array of chronic diseases in adulthood. There is a great need for scalable and effective interventions that can increase MVPA in adolescents. Here we report the results of a measurement validation study and a preliminary proof-of-concept experiment testing the impact of Zamzee, an accelerometer-linked online intervention system that combines proximal performance feedback and incentive motivation features to promote MVPA. In a calibration study that parametrically varied levels of physical activity in 31 12-14 year-old children, the Zamzee activity meter was shown to provide a valid measure of MVPA (sensitivity in detecting MVPA = 85.9%, specificity = 97.5%, and r = .94 correspondence with the benchmark RT3 accelerometer system; all p < .0001). In a subsequent randomized controlled multi-site experiment involving 182 middle school-aged children assessed for MVPA over 6 wks, intent-to-treat analyses found that those who received access to the Zamzee intervention had average MVPA levels 54% greater than those of a passive control group (p < 0.0001) and 68% greater than those of an active control group that received access to a commercially available active videogame (p < .0001). Zamzee’s effects on MVPA did not diminish significantly over the course of the 6-wk study period, and were statistically significant in both females and males, and in normal- vs. high-BMI subgroups. These results provide promising initial indications that combining the Zamzee activity meter with online proximal performance feedback and incentive motivation features can positively impact MVPA levels in adolescents.

Intermonitor Variability of RT3 Accelerometer during Different Activities

Purpose of this study was to analyze reliability and variability of the RT3 accelerometers. The RT3 was administrated to two repeated trials of six activities; rest, two steps, walking, and two running. One person performed all trials (male: age 28 yr, 169cm, 63kg). Each activity lasted 12min. Data were analyzed for activity, monitor, and trial effects. The replacement of monitors also analyzed for left and right side differences and association between heart rate and accelerometer counts was analyzed. A three-way interaction was found for vector magnitude (F35.0 = 190732.08 p<0.029) and X (F35.0 = 267589.97, p<0.001) and Y (F35.0 = 182169.56, p<0.001) and Z axes (F35.0 = 815995.11, p<0.001). A two way interaction was found for VM (p<0.002), X, Y, and Z axes (p<0.001). Placement differences between right and left monitors were found for vector magnitude, X and Z axes. At both trials 1 and 2 there was no significant heart rate differences. The Y axis of the RT3 accelerometer was the most reliable in this study. RT3 accelerometer is reliable for physical activity level.

Ability of RT3 accelerometer cut points to detect physical activity intensity in ambulatory children with cerebral palsy.

This study investigated the ability of published cut points for the RT3 accelerometer to differentiate between levels of physical activity intensity in children with cerebral palsy (CP). Oxygen consumption (metabolic equivalents; METs) and RT3 data (counts/min) were measured during rest and 5 walking trials. METs and corresponding counts/min were classified as sedentary, light physical activity (LPA), and moderate to vigorous physical activity (MVPA) according to MET thresholds. Counts were also classified according to published cut points. A published cut point exhibited an excellent ability to classify sedentary activity (sensitivity=89.5%, specificity=100.0%). Classification accuracy decreased when published cut points were used to classify LPA (sensitivity=88.9%, specificity=79.6%) and MVPA (sensitivity=70%, specificity=95-97%). Derivation of a new cut point improved classification of both LPA and MVPA. Applying published cut points to RT3 accelerometer data collected in children with CP may result in misclassification of LPA and MVPA.

A review of preschool children's physical activity and sedentary time using objective measures.

Identifying current physical activity levels and sedentary time of preschool children is important for informing government policy and community initiatives. This paper reviewed studies reporting on physical activity and time spent sedentary among preschool-aged children (2-5 years) using objective measures. Databases were searched for studies published up to and including April 2013 that reported on, or enabled the calculation of, the proportion of time preschool children spent sedentary and in light- and moderate to vigorous-intensity physical activity. A total of 40 publications met the inclusion criteria for physical activity and 31 met the inclusion criteria for sedentary time. Objective measures included ActiGraph, Actiwatch, Actical, Actiheart, and RT3 accelerometers, direct observation, and Quantum XL telemetry heart rate monitoring. Data were analyzed in May 2013. Considerable variation in prevalence estimates existed. The proportion of time children spent sedentary ranged from 34% to 94%. The time spent in light-intensity physical activity and moderate to vigorous-intensity physical activity ranged from 4% to 33% and 2% to 41%, respectively. The considerable variation of prevalence estimates makes it difficult to determine the "true" prevalence of physical activity and sedentary time in preschool children. Future research should aim to reduce inconsistencies in the employed methodologies to better understand preschoolers' physical activity levels and sedentary behavior.

Shoulder physical activity, functional disability and task difficulties in patients with stiff shoulders: Interpretation from RT3 accelerator

We determined whether the degree of symptom-related functional disability was related to daily physical activity of the shoulder in subjects with stiff shoulders (SSs). Responsiveness and a clinically meaningful level of discrimination between improvement and non-improvement for shoulder physical activity (SPA) were determined. Twenty-six subjects with SSs participated. Shoulder physical activity was assessed by RT3 accelerometers fixed on the humerus during daily 14-h data collection periods twice a week for 2 weeks. A moderate correlation coefficient was found between SPA and functional disability (β = .47). Based on our cohort design and sample, we suggest that SPA (higher than 101.8 counts, hard-moderate or hard tasks) during daily activity are associated with (with at least 83% probability) non-improvement in an individual with SS. Compared to the non-improvement group, the improvement group had less duration of sedentary activity, less frequency and duration of hard tasks, and more frequency and duration of easy tasks (p < 0.01). Appropriate guidance on shoulder physical activities for subjects with SS is important to consider in rehabilitation strategies for these subjects. In our sample, a hard level of shoulder physical activity and sedentary activity should be cautious for these subjects. Further study is needed to validate therapeutic effect of physical activity on the course of patient improvement in subjects with SSs.

Testing the ‘teachable moment’ premise: does physical activity increase in the early survivorship phase?

Little is known about objectively measured physical activity during the early survivorship period. This study measured physical activity, fatigue, and quality of life (QOL) in breast cancer patients over the first year after completion of chemotherapy and compared results to a matched non-cancer group. Data was obtained from 24 breast cancer subjects (mean ± SD) 50.9 ± 12.8 years at time points of 6 weeks, 6 months and 1 year after completion of adjuvant chemotherapy and from 20 matched women. The following variables were assessed, physical activity (RT3 accelerometer and International Physical Activity Questionnaire), quality-of-life (EORTC QLQ C-30) and fatigue (Brief Fatigue Inventory). At 6 weeks after completion of chemotherapy, high levels of sedentary behaviour were found (6.8 ± 1.9 h sedentary per day), which did not improve, and was no different to the comparison group (6.5 ± 1.4 h). Less light activity was performed in the cancer cohort compared to the comparison group (p = 0.003). Body mass index (BMI) increased significantly in the cancer cohort (p = 0.015) and 1 year after chemotherapy finished only 13% (n = 3) had a BMI <25, while the comparable value was 45% (n = 9) in the non-cancer group. The QOL domain of cognitive function improved over the first 6 months (p = 0.034) but physical functioning declined (p = 0.008) over this time period. Fatigue did not change, and at the 1-year time point, 38% of the cancer patients (n = 11) reported high levels of fatigue. This study highlighted the unchanging sedentary behaviour and weight gain of breast cancer survivors during the first year after completion of chemotherapy, which may inform rehabilitation models in this population.

Comparison of intensity-based cut-points for the RT3 accelerometer in youth

To compare the classification accuracy of previously published RT3 accelerometer cut-points for youth using energy expenditure, measured via portable indirect calorimetry, as a criterion measure. Cross-sectional cross-validation study. 100 children (mean age 11.2 ± 2.8 years, 61% male) completed 12 standardized activities trials (3 sedentary, 5 lifestyle and 4 ambulatory) while wearing an RT3 accelerometer. VO2 was measured concurrently using the Oxycon Mobile portable calorimeter. Cut-points by Vanhelst (VH), Rowlands (RW), Chu (CH), Kavouras (KV) and the RT3 manufacturer (RT3M) were used to classify PA intensity as sedentary (SED), light (LPA), moderate (MPA) or vigorous (VPA). Classification accuracy was evaluated using the area under the Receiver Operating Characteristic curve (ROC-AUC) and weighted Kappa (κ). For moderate-to-vigorous PA (MVPA), VH, KV and RW exhibited excellent accuracy classification (ROC-AUC ≥ 0.90), while the CH and RT3M exhibited good classification accuracy (ROC-AUC>0.80). Classification accuracy for LPA was fair to poor (ROC-AUC<0.76). For SED, VH exhibited excellent classification accuracy (ROC-AUC>0.90), while RW, CH, and RT3M exhibited good classification accuracy (ROC-AUC>0.80). Kappa statistics ranged from 0.67 (VH) to 0.55 (CH). All cut-points provided acceptable classification accuracy for SED and MVPA, but limited accuracy for LPA. On the basis of classification accuracy over all four levels of intensity, the use of the VH cut-points is recommended.

Global Positioning System Watches for Estimating Energy Expenditure

Global positioning system (GPS) watches have been introduced commercially, converting frequent measurements of time, location, speed (pace), and elevation into energy expenditure (EE) estimates. The purpose of this study was to compare EE estimates of 4 different GPS watches (Forerunner, Suunto, Polar, Adeo), at various walking speeds, with EE estimate from a triaxial accelerometer (RT3), which was used as a reference measure in this study. Sixteen healthy young adults completed the study. Participants wore 4 different GPS watches and an RT3 accelerometer and walked at 6-minute intervals on an outdoor track at 3 speeds (3, 5, and 7 km/hr). The statistical significance of differences in EE between the 3 watches was assessed using linear contrasts of the coefficients from the overall model. Reliability across trials for a given device was assessed using intraclass correlation coefficients as estimated in the mixed model. The GPS watches demonstrated lower reliability (intraclass correlation coefficient) across trials when compared with the RT3, particularly at the higher speed, 7 km/hr. Three GPS watches (Forerunner, Polar, and Suunto) significantly and consistently underestimated EE compared with the reference EE given by the RT3 accelerometer (average mean difference: Garmin, -50.5%; Polar, -41.7%; and Suunto, -41.7%; all p < 0.001). Results suggested that caution should be exercised when using commercial GPS watches to estimate EE in athletes during field-based testing and training.

Does a patient’s physical activity predict recovery from an episode of acute low back pain? A prospective cohort study

BackgroundAdvice to remain active and normalisation of activity are commonly prescribed in the management of low back pain (LBP). However, no research has assessed whether objective measurements of physical activity predict outcome and recovery in acute low back pain.MethodThe aims of this study were to assess the predictive relationship between activity and disability at 3 months in a sub-acute LBP population. This prospective cohort study recruited 101 consenting patients with sub-acute LBP (< 6 weeks) who completed the Roland Morris Disability Questionnaire (RMDQ), the Visual Analogue Scale, and resumption of full ‘normal’ activity question (Y/N), at baseline and 3 months. Physical activity was measured for 7 days at both baseline and at 3 months with an RT3 accelerometer and a recall questionnaire.ResultsObserved and self-reported measures of physical activity at baseline and change in activity from baseline to 3 months were not independent predictors of RMDQ (p > 0.05) or RMDQ change (p > 0.05) over 3 months. A self-report of a return to full ‘normal’ activities was significantly associated with greater RMDQ change score at 3 months (p < 0.001). Paired t-tests found no significant change in activity levels measured with the RT3 (p = 0.57) or the recall questionnaire (p = 0.38) from baseline to 3 months.ConclusionsThese results question the predictive role of physical activity in LBP recovery, and the assumption that activity levels change as LBP symptoms resolve. The importance of a patient’s perception of activity limitation in recovery from acute LBP was also highlighted.Trial registrationClinical Trial Registration Number, ACTRN12609000282280

Concurrent Validity of the Modified International Physical Activity Questionnaire for French Obese Adolescents

Physical activity is an important component of a healthy lifestyle. Evaluating and promoting this activity warrants careful attention, particularly in the context of preventing obesity associated with low physical activity. The aim of the present study was to assess the concurrent validity of a modified, long, self-administered version of the International Physical Activity Questionnaire (IPAQ) using triaxial accelerometry in 56 youth with obesity. The participants' physical activity was measured with an RT3 accelerometer (objective measure) and with the International Physical Activity Questionnaire for Adolescents (IPAQ-A; subjective measure). Although the two methods were correlated strongly (r = .84), there was a significant difference between the two methods. The participants' subjective ratings on the IPAQ-A overestimated the objective measure. Although activity questionnaires are simple and widely used in assessing physical activity, alternative methods should be used when measuring physical activity in youth with obesity.

Calibration of ActiGraph GT3X, Actical and RT3 accelerometers in Brazilian adolescents

Introduction: The use of accelerometers to investigate physical activity has increased sharply in the last years, even outside high-income countries. However, there is no evidence that thresholds of accelerometers counts developed from high income countries can be valid for other settings. The different types of physical activities practiced across populations might play a role in this issue. The objective of this study was to develop thresholds for counts of ActiGraph GT3X, RT3 and Actical accelerometers in order to classify different physical activity intensities in Brazilian adolescents.