Effects of walking speed and step frequency on estimation of physical activity using accelerometers

Data Analytics in Physical Activity Studies With Accelerometers: Scoping Review

BACKGROUND

Monitoring free-living physical activity (PA) through wearable devices enables the real-time assessment of activity features associated with health outcomes and provision of treatment recommendations and adjustments. The conclusions of studies on PA and health depend crucially on reliable statistical analyses of digital data. Data analytics, however, are challenging due to the various metrics adopted for measuring PA, different aims of studies, and complex temporal variations within variables. The application, interpretation, and appropriateness of these analytical tools have yet to be summarized.

OBJECTIVE

This research aimed to review studies that used analytical methods for analyzing PA monitored by accelerometers. Specifically, this review addressed three questions: (1) What metrics are used to describe an individual's free-living daily PA? (2) What are the current analytical tools for analyzing PA data, particularly under the aims of classification, association with health outcomes, and prediction of health events? and (3) What challenges exist in the analyses, and what recommendations for future research are suggested regarding the use of statistical methods in various research tasks?

METHODS

This scoping review was conducted following an existing framework to map research studies by exploring the information about PA. Three databases, PubMed, IEEE Xplore, and the ACM Digital Library, were searched in February 2024 to identify related publications. Eligible articles were classification, association, or prediction studies involving human PA monitored through wearable accelerometers.

RESULTS

After screening 1312 articles, 428 (32.62%) eligible studies were identified and categorized into at least 1 of the following 3 thematic categories: classification (75/428, 17.5%), association (342/428, 79.9%), and prediction (32/428, 7.5%). Most articles (414/428, 96.7%) derived PA variables from 3D acceleration, rather than 1D acceleration. All eligible articles (428/428, 100%) considered PA metrics represented in the time domain, while a small fraction (16/428, 3.7%) also considered PA metrics in the frequency domain. The number of studies evaluating the influence of PA on health conditions has increased greatly. Among the studies in our review, regression-type models were the most prevalent (373/428, 87.1%). The machine learning approach for classification research is also gaining popularity (32/75, 43%). In addition to summary statistics of PA, several recent studies used tools to incorporate PA trajectories and account for temporal patterns, including longitudinal data analysis with repeated PA measurements and functional data analysis with PA as a continuum for time-varying association (68/428, 15.9%).

CONCLUSIONS

Summary metrics can quickly provide descriptions of the strength, frequency, and duration of individuals' overall PA. When the distribution and profile of PA need to be evaluated or detected, considering PA metrics as longitudinal or functional data can provide detailed information and improve the understanding of the role PA plays in health. Depending on the research goal, appropriate analytical tools can ensure the reliability of the scientific findings.

Physical Activity and Its Diurnal Fluctuations Vary by Non-Motor Symptoms in Patients with Parkinson's Disease: An Exploratory Study

Background: This exploratory study investigated the association between non-motor symptoms (NMS) and both physical activity and diurnal activity patterns in patients with Parkinson’s disease (PwPD). Methods: Participants included PwPD with modified Hoehn and Yahr stages 1−3. The presence of NMS was assessed with Movement Disorder Society-Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) Part I. Physical activity was measured using a waist-mounted triaxial accelerometer. Logistic regression analyses evaluated associations between NMS and physical activity; furthermore, diurnal fluctuation in physical activity due to NMS was examined by ANCOVA. Results: Forty-five PwPD were included in the study. Among the domains of NMS, pain and other sensations (OR, 8.36; 95% CI, 1.59−43.94) and fatigue (OR, 14.26; 95% CI, 1.85−109.90) were associated with low daily step count (<4200 steps/day). Analysis by time of day showed no characteristic variability in physical activity but had constant effect sizes for pain and other sensations (p = 0.20, ES = 0.36) and fatigue (p = 0.08, ES = 0.38). Conclusion: Our exploratory study suggested that PwPD with pain and other sensations and fatigue recorded lower step counts than their asymptomatic counterparts. Therefore, PwPD with pain and fatigue may need more support in promoting physical activity.

Association between low level of physical activity and mobility limitation in older adults: evidence from the SABE study

Several studies are limited by verifying the level of physical activity with questionnaires and not through objective measurement in older adults. This article aims to analyze the association between a low level of physical activity with accelerometry) and mobility limitation in older adults. A population-based cross-sectional study conducted with 543 older adults. Multiple regression analysis was performed using hierarchical analysis, grouping the variables into two blocks ordered according to the precedence with which they acted on the outcomes. Among the evaluated older adults, 13.7% presented mobility limitations and among these 60.39% were in the low level of physical activity group. Older adults with a low level of physical activity (OR = 3.49 [2.0 - 6.13]), aged 75 and over (OR = 1.97 [1.03 - 3.72]), living without a partner (OR = 2.01 [1.09 - 3.68]), having difficulty performing basic (OR = 2.49 [1.45 - 4.28]) and instrumental (OR = 2.28) [1.18 - 4.36]) activities of daily life, and multimorbidity (OR = 2.06 [1.04 - 4.08]) were independently associated with mobility limitation. A low level of physical activity increases the chance of mobility limitation in older adults, regardless of sociodemographic and clinical variables.

Factors Associated with Reduction of Sedentary Time Following Tiotropium/Olodaterol Therapy in Treatment-Naïve Chronic Obstructive Pulmonary Disease

Background

Prolonged sedentary behavior is associated with worse prognosis in patients with chronic obstructive pulmonary disease (COPD). Our previous study found that first-line dual therapy with tiotropium/olodaterol significantly reduces sedentary time compared to tiotropium monotherapy in Japanese patients with treatment-naïve COPD, although the characteristics of responders to dual-therapy versus monotherapy for COPD are still unclear.

Methods

Patients with treatment-naïve COPD were randomized to receive either tiotropium or tiotropium/olodaterol treatment for 12 weeks. Physical activity was assessed using a triaxle accelerometer for 2 weeks before and after treatment. This analysis focused on the change in sedentary time, indicated by physical activity of 1.0–1.5 metabolic equivalents (METs), with stratification for the following factors: age, body mass index (BMI), pulmonary function, COPD assessment test (CAT), the 6-minute walk distance (6MWD), and physical activity level at study entry.

Results

Thirty-five patients received tiotropium/olodaterol and 34 patients received tiotropium. In patients with lower inspiratory capacity at study entry, a significant reduction in sedentary time was observed in the tiotropium/olodaterol group compared with the tiotropium group (Tio: −12.8 ± 13.5 min, Tio/Olo: −65.1 ± 21.0 min, mean difference, −52.2 min, 95% CI −103.6 to 0.88, p = 0.046). In patients with a shorter duration of physical activity of ≥2 METs at study entry, a significant reduction of sedentary time was observed in the tiotropium/olodaterol group compared with the tiotropium group (Tio: −3.3 ± 17.5 min, Tio/Olo: −72.9 ± 23.1 min, mean difference, −69.7 min, 95% CI −128.7 to −10.6, p = 0.02). There were no differences in terms of age, BMI, CAT score, 6MWD, FEV1, FVC, VC, and physical activity of 1.0–1.5 METs and ≥3.0 METs.

Conclusion

This study showed that COPD patients with lower inspiratory capacity or shorter active time of ≥2.0 METs at study entry are likely to exhibit significantly greater reduction in sedentary time with tiotropium/olodaterol treatment.

Associations between psychological factors and daily step count in patients with lumbar spinal stenosis

Background: Body mass index, pain, female sex, and age have been reported as predictors of physical activity in patients with lumbar spinal stenosis (LSS). However, no reports have examined the psychological factors associated with physical activity in people with LSS.Purpose: To use psychological assessments to identify the factors associated with physical activity measured as daily step count in people with LSS.Methods: Seventy-one patients who received outpatient physical therapy were included. All patients completed the following scales at baseline: Zurich Claudication Questionnaire; self-paced walking test (SPWT); numerical rating scale of low back pain, leg pain, and leg numbness; Hospital Anxiety and Depression Scale (HADS); Pain Catastrophizing Scale; Pain Anxiety Symptoms Scale (PASS-20); and Tampa Scale for Kinesiophobia. Physical activity was measured using a pedometer as the average number of daily steps.Results: Daily step count was significantly associated with age, number of stenoses, severity of stenosis at L3-L4, walking distance on the SPWT, PASS-20 total score, cognitive anxiety, escape/avoidance, fear, and HADS depression score (p < .05). Multiple regression analysis showed that age, severity of stenosis at L3-L4, walking distance on the SPWT, and PASS-20 fear predicted daily step count (r² = 0.414).Conclusion: Older age, fewer stenoses, less severe stenosis at L3-L4, lower walking capacity, higher anxiety, and fear-avoidance beliefs about pain and depression are more closely associated with lower daily step count than are back and leg pain. Assessment and treatment of psychological factors might help to increase physical activity in patients with LSS.

Random forest algorithms for recognizing daily life activities using plantar pressure information: a smart-shoe study

Background

Wearable activity trackers are regarded as a new opportunity to deliver health promotion interventions. Indeed, while the prediction of active behaviors is currently primarily relying on the processing of accelerometer sensor data, the emergence of smart clothes with multi-sensing capacities is offering new possibilities. Algorithms able to process data from a variety of smart devices and classify daily life activities could therefore be of particular importance to achieve a more accurate evaluation of physical behaviors. This study aims to (1) develop an activity recognition algorithm based on the processing of plantar pressure information provided by a smart-shoe prototype and (2) to determine the optimal hardware and software configurations.

Method

Seventeen subjects wore a pair of smart-shoe prototypes composed of plantar pressure measurement insoles, and they performed the following nine activities: sitting, standing, walking on a flat surface, walking upstairs, walking downstairs, walking up a slope, running, cycling, and completing office work. The insole featured seven pressure sensors. For each activity, at least four minutes of plantar pressure data were collected. The plantar pressure data were cut in overlapping windows of different lengths and 167 features were extracted for each window. Data were split into training and test samples using a subject-wise assignment method. A random forest model was trained to recognize activity. The resulting activity recognition algorithms were evaluated on the test sample. A multi hold-out procedure allowed repeating the operation with 5 different assignments. The analytic conditions were modulated to test (1) different window lengths (1–60 seconds), (2) some selected sensor configurations and (3) different numbers of data features.

Results

A window length of 20 s was found to be optimum and therefore used for the rest of the analysis. Using all the sensors and all 167 features, the smart shoes predicted the activities with an average success of 89%. “Running” demonstrated the highest sensitivity (100%). “Walking up a slope” was linked with the lowest performance (63%), with the majority of the false negatives being “walking on a flat surface” and “walking upstairs.” Some 2- and 3-sensor configurations were linked with an average success rate of 87%. Reducing the number of features down to 20 does not alter significantly the performance of the algorithm.

Conclusion

High-performance human behavior recognition using plantar pressure data only is possible. In the future, smart-shoe devices could contribute to the evaluation of daily physical activities. Minimalist configurations integrating only a small number of sensors and computing a reduced number of selected features could maintain a satisfying performance. Future experiments must include a more heterogeneous population.

A validation study of the use of smartphones and wrist-worn ActiGraphs to measure physical activity at different levels of intensity and step rates in older people

BACKGROUND

Physical activity promotes healthy ageing in older people. Accurate measurement of physical activity in free-living environment is important in evaluating physical activity interventions.

RESEARCH QUESTION

What is the criterion validity of 1)an ActiGraph to identify physical activity at different intensity levels and 2)an ActiGraph and a smartphone to measure step rate?

METHODS

Community-dwelling older people aged≥60 were recruited. The index tests were using ActiGraph worn in different positions (i.e.,both wrists and hip) to measure physical activity intensity and step rate and using smartphone (i.e., Samsung J2 pro and Google Fit) worn in different positions (i.e.,trousers pocket and waist pouch) to measure the step rate. The reference standards were using indirect calorimetry (i.e.,CosMedK4b 2) to measure physical activity intensity and using direct observation for step rate. Subjects were exposed in different physical activity intensity levels (i.e.,sedentary:MET < 1.5,light: MET = 1.5-2.99, moderate:MET = 3.0-6.0, vigorous:MET>6) and step rates through walking on a treadmill at different speeds (i.e.,2-8 km) for approximately 30 min. Spearman's rho, ROC analysis, and percentage error were employed to report the criterion validity.

RESULTS

31 participants completed the tests. ActiGraphs worn in different body positions could significantly differentiate physical activity intensity at the levels of "light- or-above" (VM cut-off = 279.5-1959.1,AUC = 0.932-0.954), "moderate-or-above" (VM cut- off = 1051.0-4212.9,AUC = 0.918-0.932), and "vigorous" (VM cut-off = 3335.4-5093.0, AUC = 0.890-0.907) well with different cut-off points identified. The step rate measured by direct observation correlated significantly with ActiGraph and smartphone (rho = 0.415-0.791). Both ActiGraph and smartphone at different positions generally underestimated the step rate (%error= -20.5,-30.3).

SIGNIFICANCE

A wrist-worn ActiGraph can accurately identify different physical activity intensity levels in older people, but lower cut-off points in older people should be adopted. To measure step rate, a hip-mounted ActiGraph is preferable than a wrist- worn one. A smartphone employing Google Fit generally underestimates step rate but it gives a relatively more accurate estimation of step rate when the older people walk at a speed of 4-8 km/h.

First-Line Treatment with Tiotropium/Olodaterol Improves Physical Activity in Patients with Treatment-Naïve Chronic Obstructive Pulmonary Disease

Background

Comparative effects on physical activity of mono and dual bronchodilators remain unclear in patients with treatment-naïve chronic obstructive pulmonary disease (COPD). We sought to compare the changes in physical activity before and after tiotropium and tiotropium/olodaterol treatment in treatment-naïve COPD patients.

Methods

A prospective, multicenter, randomized, open-labeled, and parallel interventional study was conducted. Eighty Japanese patients with treatment-naïve COPD were randomized to receive either tiotropium or tiotropium/olodaterol treatment for 12 weeks. Spirometry and dyspnea index were assessed, and COPD assessment test (CAT) and the 6-minute walk distance (6MWD) were conducted before and after treatment. Evaluation of physical activity was assessed by a triaxle accelerometer over a 2-week period before and after treatment.

Results

There were no differences in the mean age (69.8 vs 70.4 years), body mass index (BMI) (22.5 vs 22.6 kg/m²) and mean % forced expiratory volume in 1 second (%FEV1) at baseline (61.5 vs 62.6%) between the two groups. Changes in FEV1 (mean±standard error, 242.8±28.8 mL) and transient dyspnea index (TDI) (2.4±0.3 points) before and after tiotropium/olodaterol treatment were greater than with tiotropium treatment (104.1±31.9 mL, p<0.01 and 1.5±0.3, p=0.02, respectively). Changes in the duration of physical activity with 1.0–1.5 metabolic equivalents (METs) estimated in the sedentary position following tiotropium/olodaterol treatment (−38.7±14.7 min) tended to be reduced more than with tiotropium treatment (−4.6±10.6 min) (p=0.06), although those with ≥2.0 METs numerically increased with both treatments (+10.8±7.6 min for tiotropium/olodaterol vs +8.3±7.6 min for tiotropium, p=0.82). Tiotropium/olodaterol treatment reduced the duration of physical activity with 1.0–1.5 METs (regression coefficient, −43.6 [95% CI −84.1, −3.1], p=0.04) in a multiple regression model adjusted for cofounding factors such as age, FEV1, total CAT scores, 6MWD, and TDI.

Conclusion

This is the first study to report the impact of dual bronchodilator on physical activity in treatment-naïve COPD patients of Japanese with low BMI.

Diurnal Profiles of Locomotive and Household Activities Using an Accelerometer in Community-Dwelling Older Adults with Musculoskeletal Disorders: A Cross-Sectional Survey

The present study investigates the diurnal profiles of locomotive and household activities in older adults with musculoskeletal disorders (MSDs) using an accelerometer. Furthermore, we examined the effect of chronic pain on their diurnal profiles in both activities. Seventy-one older adults with MSDs (73-89 years) were included in this cross-sectional survey, and 25 age-matched older adults (75-86 years) were selected as healthy older adults. The daily physical activities, including steps walked and locomotive and household activity intensities, were recorded using a triaxial accelerometer in terms of metabolic equivalent task-hours per week (MET-h/week). The diurnal profiles of steps and locomotive activities in older adults with MSDs were considerably lower than those of healthy older adults. In contrast, there was no significant decline in household activity. However, the locomotive and household activities were reduced by severe chronic pain. This survey demonstrated that the diurnal profiles of household activity in older people with MSDs as well as those in age-matched healthy older adults were maintained. Furthermore, severe chronic pain influenced both activities. Therefore, the maintenance of household activity throughout the day, as well as the management of chronic pain, may be important strategies for the promotion of physical activity in older people with MSDs.

Using physical activity levels to estimate energy requirements of female athletes

[Purpose]

The goal of this study was to review data on physical activity level (PAL), a crucial index for determining estimated energy requirement (EER), calculated as total energy expenditure (TEE, assessed with doubly labeled water [DLW]) divided by resting metabolic rate (RMR, PAL = TEE/RMR) in female athletes and to understand the methods of assessing athletes’ EERs in the field.

[Methods]

For the PAL data review among female athletes, we conducted a PubMed search of the available literature related to the DLW method. DLW studies measuring TEE and RMR were included for the present review.

[Results]

Briefly, the mean PAL was 1.71 for collegiate swimmers with moderate training, which was relatively low, but the mean PAL was 3.0 for elite swimmers during summer training camp. This shows that PAL can largely vary even within the same sport depending on the amount of training, and the differences in PAL were remarkable depending on the sport. Aside from the DLW method, there is currently no research tool related to athletes’ EERs that can be used in the field.

[Conclusion]

Briefly, the mean PAL was 1.71 for collegiate swimmers with moderate training, which was relatively low, but the mean PAL was 3.0 for elite swimmers during summer training camp. This shows that PAL can largely vary even within the same sport depending on the amount of training, and the differences in PAL were remarkable depending on the sport. Aside from the DLW method, there is currently no research tool related to athletes’ EERs that can be used in the field.

Validity of estimating physical activity intensity using a triaxial accelerometer in healthy adults and older adults

Background

A triaxial accelerometer with an algorithm that could discriminate locomotive and non-locomotive activities in adults has been developed. However, in the elderly, this accelerometer has not yet been validated. The aim were to examine the validity of this accelerometer in the healthy elderly, and to compare the results with those derived in a healthy younger sample.

Methods

Twenty-nine healthy elderly subjects aged 60–80 years (Elderly), and 42 adults aged 20–59 years (Younger) participated. All subjects performed 11 activities, including locomotive and non-locomotive activities with a Douglas bag while wearing the accelerometer (Active style Pro HJA-750C). Physical activity intensities were expressed as metabolic equivalents (METs). The relationship between the METs measured using the Douglas bag and METs predicted using the accelerometer was evaluated.

Results

A significant correlation between actual and predicted METs was observed in both Elderly (r=0.85, p<0.001) and Younger (r=0.88, p<0.001). Predicted METs significantly underestimated compared with actual METs in both groups (p<0.001). The mean of the errors was −0.6±0.6 METs in Elderly and −0.1±0.5 METs in Younger. The degree of underestimation increased with increasing METs in Elderly (p<0.001). A stepwise multiple regression analysis revealed that predicted METs, age, and weight were related to actual METs in both groups.

Conclusion

The degree of correlation between predicted and actual METs was comparable in elderly and younger participants, but the prediction errors were greater in elderly participants, particular at higher-intensity activities, which suggests that different predicting equations may be needed for the elderly.

Physical Activity and Sedentary Behavior Assessment: A Laboratory-Based Evaluation of Agreement between Commonly Used ActiGraph and Omron Accelerometers

Different models of accelerometer have the potential to provide a different estimate of the same physical activity or sedentary behavior. Our study compared the outputs of the Active Style Pro (ASP) and ActiGraph (AG) devices in assessing predicted metabolic equivalents (METs) for specific activities under laboratory conditions. Thirty healthy young adults wore two hip accelerometers (ASP and AG), simultaneously while performing twenty-two activities (eight sedentary, eight household, and six ambulatory activities) in a controlled laboratory setting. For the AG, predicted METs for each activity was calculated using four equations based on vertical-axis and vector magnitude data. Separate paired t-tests and Bland–Altman analysis examined the difference and agreement in METs between AG using four commonly used equations and ASP measurements for each activity. AG devices using different equations calculated significantly different outcomes for most activities compared with ASP devices. The smallest differences in predicted METs estimates between ASP and AG were observed for ambulatory activities. Ambulatory activities demonstrated the best agreement between ASP and AG regardless of which AG equation was used. Our findings can be used to assist researchers in their selection of accelerometer and output estimation equations for measuring physical activity and sedentary behavior in adults.

Assessing Physical Activity and Sedentary Behavior under Free-Living Conditions: Comparison of Active Style Pro HJA-350IT and ActiGraphTM GT3X

Various accelerometers have been used in research measuring physical activity (PA) and sedentary behavior (SB). This study compared two triaxial accelerometers—Active style Pro (ASP) and ActiGraph (AG)—in measuring PA and SB during work and nonwork days in free-living conditions. A total of 50 working participants simultaneously wore these two accelerometers on one work day and one nonwork day. The difference and agreement between the ASP and AG were analyzed using paired t-tests, Bland–Altman plots, and intraclass coefficients, respectively. Correction factors were provided by linear regression analysis. The agreement in intraclass coefficients was high among all PA intensities between ASP and AG. SB in the AG vertical axis was approximately 103 min greater than ASP. Regarding moderate-to-vigorous-intensity PA (MVPA), ASP had the greatest amount, followed by AG. There were significant differences in all variables among these devices across all day classifications, except for SB between ASP and AG vector magnitude. The correction factors decreased the differences of SB and MVPA. PA time differed significantly between ASP and AG. However, SB and MVPA differences between these two devices can be decreased using correction factors, which are useful methods for public health researchers.

Supervised physical therapy vs. home exercise for patients with lumbar spinal stenosis: a randomized controlled trial

BACKGROUND CONTEXT

Exercise has been reported to improve short-term outcomes for patients with LSS in terms of disability and back and leg pain. However, no studies have compared supervised exercise with unsupervised exercise or quantified physical activity using a pedometer to confirm compliance with a home exercise program.

PURPOSE

To compare the effectiveness of supervised physical therapy (PT) with unsupervised exercise for patients with lumbar spinal stenosis (LSS).

STUDY DESIGN/SETTING

A single-center, open-label, randomized controlled trial.

PATIENT SAMPLE

Patients presenting with symptoms of neurogenic claudication caused by LSS, which was confirmed by magnetic resonance imaging.

OUTCOME MEASURES

The primary outcome was improvement in symptom severity scores on the Zurich Claudication Questionnaire (ZCQ) at 6 weeks. Secondary outcomes included physical function on the ZCQ, self-paced walking test (SPWT) performance, pain indicated using a numerical rating scale (NRS), and the number of daily steps measured by pedometer.

METHODS

Patients with LSS were randomized to a PT group, who performed supervised PT twice a week for 6 weeks, or a home exercise (HE) group. PT sessions included manual therapy, individually tailored stretching and strengthening exercises, cycling, and body weight-supported treadmill walking.

RESULTS

Forty-three patients were randomly allocated to the PT group and 43 patients to the HE group. Compared with the HE group, the PT group had greater percentage of responders achieving minimum clinically important difference in ZCQ symptom severity (difference for percentage between groups [95%confidence interval], 30.2% [9.1-48.6], p=.01), ZCQ physical function (32.6% [11.6-50.6], p<.01), walking distance on the SPWT (39.5% [18.8-56.7], p<.01), leg pain on the NRS (34.9% [13.9-52.7], p<.01), and number of daily steps (25.6% [4.9-43.9], p=.01).

CONCLUSIONS

Supervised PT for patients with LSS resulted in significant short-term improvements in symptom severity, physical function, walking distance, pain, and physical activity compared with unsupervised exercise.

Metabolic Costs of Standing and Walking in Healthy Military-Age Adults: A Meta-regression

INTRODUCTION

The Load Carriage Decision Aid (LCDA) is a U.S. Army planning tool that predicts physiological responses of soldiers during different dismounted troop scenarios. We aimed to develop an equation that calculates standing and walking metabolic rates in healthy military-age adults for the LCDA using a meta-regression.

METHODS

We searched for studies that measured the energetic cost of standing and treadmill walking in healthy men and women via indirect calorimetry. We used mixed effects meta-regression to determine an optimal equation to calculate standing and walking metabolic rates as a function of walking speed (S, m·s). The optimal equation was used to determine the economical speed at which the metabolic cost per distance walked is minimized. The estimation precision of the new LCDA walking equation was compared with that of seven reference predictive equations.

RESULTS

The meta-regression included 48 studies. The optimal equation for calculating normal standing and walking metabolic rates (W·kg) was 1.44 + 1.94S + 0.24S. The economical speed for level walking was 1.39 m·s (~ 3.1 mph). The LCDA walking equation was more precise across all walking speeds (bias ± SD, 0.01 ± 0.33 W·kg) than the reference predictive equations.

CONCLUSION

Practitioners can use the new LCDA walking equation to calculate energy expenditure during standing and walking at speeds <2 m·s in healthy, military-age adults. The LCDA walking equation avoids the errors estimated by other equations at lower and higher walking speeds.

Daily step count of British military males with bilateral lower limb amputations: A comparison of in-patient rehabilitation with the consecutive leave period between admissions

BACKGROUND:

Reduced function and health in individuals with lower limb amputation is well documented. Step count measurement could facilitate rehabilitation and help monitor functional health outcomes.

OBJECTIVES:

To determine whether mean daily step count changed between in-patient rehabilitation and consecutive leave periods.

STUDY DESIGN:

Observational study.

METHODS:

Nine individuals with bilateral traumatic amputations attending rehabilitation at the Defence Medical Rehabilitation Centre during a 4-month period were invited to participate in the study (two bilateral transfemoral, two bilateral transfemoral/knee disarticulation, two transfemoral/transtibial, one bilateral transfemoral plus transradial, one bilateral transfemoral plus transhumeral and one transfemoral/transtibial/transradial). Prostheses worn by each participant were fitted with an activity monitor (LAM2^TM; PAL Technologies Ltd, Glasgow). Mean daily step count was analysed for each participant following 2 weeks in-patient rehabilitation and consecutive 2 weeks away from rehabilitation.

RESULTS:

Nine participants completed the study (time since injury: 19 ± 7 months, age: 26 ± 6 years). Mean daily step count significantly decreased from 2258 ± 192 during in-patient rehabilitation to 1387 ± 363 at home ( p < 0.01).

CONCLUSION:

The step count decreased when away from rehabilitation, confirming the hypothesis that the mean daily step count would change between in-patient rehabilitation and consecutive leave period.

CLINICAL RELEVANCE

These data provide an indication of the step count achievable by young, military male personnel with bilateral lower limb amputations and highlights differences between intensive in-patient rehabilitation and consecutive leave periods. It is suggested that further investigation and support of clinical monitoring could facilitate rehabilitation tailored to the individual.

Analyzing walking speeds with ankle and wrist worn accelerometers in a cohort with myotonic dystrophy

Background: Accelerometers are accurate tools to assess movement and physical activity. However, interpreting standardly used outputs is not straightforward for populations with impaired mobility.

Methods: The applicability of GENEActiv was explored in a group of 30 participants with myotonic dystrophy and compared to a group of 14 healthy-controls. All participants performed a set of tests while wearing four different accelerometers (wrists and ankles): [1] standing still; [2] ten-meters walk test; [3] six-minutes walking test; and, [4] ten-meters walk/run test.

Results: Relevant findings were: [1] high intra-accelerometer reliability (i.e. 0.97 to 0.99; p < 0.001); [2] each test acceleration values differ significantly between each other; [3] no inter-accelerometer reliability between wrist-worn devices and ankle-worn; and [4] a significant difference between the myotonic dystrophy group and the healthy-controls detectable at each test (i.e. Left-ankle values at six-minutes walking test: 48±17 for the myotonic dystrophy group, vs, 74±16 for the healthy-controls; p < 0.001).

Conclusions: GENEActiv demonstrated to be valid and reliable, capable of detecting walking periods and discriminating different speeds. However, inter-accelerometer reliability only applied when comparing opposite sides of the same limb. Specific movement characteristics of the myotonic dystrophy group were identified and muscle strength showed not to be a full determinant of limb acceleration.

Implications for rehabilitation

Rehabilitation professionals in the field of neuromuscular disorders should be aware of the potential use of objective monitoring tools such as accelerometers whilst acknowledging the implications of assessing populations with altered movement patterns.

Researchers should be cautious when translating accelerometry outputs previously validated in healthy populations to functionally impaired cohorts like myotonic dystrophy.

Accelerometers can objectively expose movement disturbances allowing further investigations for the source of these disturbances.

Comparison of daily physical activity parameters using objective methods between overweight and normal-weight children

PURPOSE

The purpose of the present study was to determine if there were any differences in various aspects of physical activity such as energy expenditure, intensity, and type of activity between normal-weight and overweight boys.

METHODS

Children aged 9-12 years were recruited from 2 elementary schools located in different urban districts in Republic of Korea. The present study included 45 Korean boys, of which 19 were normal-weight and 26 were overweight. Daily physical activity was estimated over the same 1-week study period under free-living conditions using the doubly labeled water (DLW) method and a tri-axial accelerometer. Resting metabolic rate (RMR) was measured using the Douglas bag method and open-circuit indirect calorimetry. We calculated the physical activity level (PAL) as the total energy expenditure (TEE)/RMR.

RESULTS

PAL was not significantly different between the groups. In the accelerometer data, time spent in locomotive moderate-to-vigorous physical activity (MVPA) was significantly lower in overweight boys than in normal-weight subjects, whereas other variables including non-locomotive activity did not differ between groups. In addition, among all participants, time spent in total locomotive activity was significantly associated with PAL. Time spent in locomotive MVPA was significantly associated with PAL.

CONCLUSION

Overweight boys may be less physically active based on locomotive MVPA, which was positively related with PAL. Our findings suggest that the contribution of locomotive MVPA to the increase in PAL was relatively significant.

The association of locomotive and non-locomotive physical activity measured by an accelerometer with functional fitness in healthy elderly men: a pilot study

PURPOSE

The purpose of this study was to investigate the relationship of various aspects of daily physical activity, such as the number of steps, time spent in moderate to vigorous intensity physical activity (MVPA), and locomotive and non-locomotive MVPA measured by a triaxial accelerometer, with the functional fitness in healthy elderly men.

METHODS

The subjects of this study were 22 healthy elderly men aged over 65 years. The participants wore a triaxial accelerometer for two weeks to estimate their daily physical activities. The level of functional fitness was measured based on "National Fitness Award 100 in Korea" immediately after the measurement of two weeks of daily physical activities.

RESULTS

The results showed that active healthy elderly men with more than 6,500 walking steps per day and more than 60 min per day spent in MVPA showed a significantly higher 2-min marching in place and index of cardiorespiratory endurance compared to less physically active participants. Particularly, locomotive MVPA was significantly associated with cardiorespiratory endurance levels (r = 0.50), whereas non-locomotive MVPA was not associated with other measurements of functional fitness.

CONCLUSION

Increased MVPA time, especially the locomotive MVPA, can effectively suppress the decrease in cardiorespiratory endurance level in elderly men. However, no association was observed between non-locomotive MVPA, such as household activities, and functional fitness in healthy elderly men.

A systematic literature review of reviews on techniques for physical activity measurement in adults: a DEDIPAC study

The links between increased participation in Physical Activity (PA) and improvements in health are well established. As this body of evidence has grown, so too has the search for measures of PA with high levels of methodological effectiveness (i.e. validity, reliability and responsiveness to change). The aim of this “review of reviews” was to provide a comprehensive overview of the methodological effectiveness of currently employed measures of PA, to aid researchers in their selection of an appropriate tool. A total of 63 review articles were included in this review, and the original articles cited by these reviews were included in order to extract detailed information on methodological effectiveness.

Self-report measures of PA have been most frequently examined for methodological effectiveness, with highly variable findings identified across a broad range of behaviours. The evidence-base for the methodological effectiveness of objective monitors, particularly accelerometers/activity monitors, is increasing, with lower levels of variability observed for validity and reliability when compared to subjective measures. Unfortunately, responsiveness to change across all measures and behaviours remains under-researched, with limited information available.

Other criteria beyond methodological effectiveness often influence tool selection, including cost and feasibility. However, researchers must be aware of the methodological effectiveness of any measure selected for use when examining PA. Although no “perfect” tool for the examination of PA in adults exists, it is suggested that researchers aim to incorporate appropriate objective measures, specific to the behaviours of interests, when examining PA in free-living environments.

Total energy expenditure of 10- to 12-year-old Japanese children measured using the doubly labeled water method

Background

To establish Japanese children's estimated energy requirements, total energy expenditure (TEE) data measured using the doubly labeled water (DLW) method is needed. This study aimed to 1) obtain basic TEE data from Japanese children measured using DLW (TEE_DLW), 2) compare TEE_DLW with TEE estimated by various estimation formulas to calculate their accuracy, and 3) develop a new equation to estimate TEE using body composition and pedometers.

Methods

TEE was measured using DLW in 56 10- to 12-year-old Japanese children (33 boys, 23 girls). Physical activity level (PAL) was calculated by dividing TEE_DLW by estimated resting energy expenditure. To assess their physical activity, participants wore pedometers during the 7-d DLW period. Total body water was calculated from ²H and ¹⁸O; fat-free mass (FFM) and fat mass (FM) were then determined.

Results

In boys and girls of normal weight, TEE_DLW was 2067 ± 230 kcal/d and 1830 ± 262 kcal/d, respectively. Average PAL was 1.58 ± 0.17. FFM was strongly related to TEE (r = 0.702, p < 0.01). After adjusting for FFM and FM, step count was significantly associated with TEE (r = 0.707, p < 0.01). The TEE estimation formula used in the Dietary Reference Intakes (DRI) for the United States and Canada estimated TEE_DLW with high accuracy (bias: 2.0%) in both sexes. We developed new equations for TEE consisting of FFM and step count, which accounted for 68% and 65% of TEE variance in boys and girls, respectively: boys, 47.1 × FFM (kg) + 0.0568 × step count (steps/d) - 122, and girls, 55.5 × FFM (kg) + 0.0315 × step count (steps/d) - 117.

Conclusions

The TEE in 10- to 12-year-old Japanese children measured using DLW was approximately 7% lower for boys and 12% lower for girls compared to the current Japanese DRI. If PAL can be accurately determined, the equation in the DRI for the United States and Canada may be applicable to Japanese children. In addition, TEE could be predicted using FFM and step count.

Extended, continuous measures of functional status in community dwelling persons with Alzheimer's and related dementia: Infrastructure, performance, tradeoffs, preliminary data, and promise

BACKGROUND

The past decades have seen phenomenal growth in the availability of inexpensive and powerful personal computing devices. Efforts to leverage these devices to improve health care outcomes promise to remake many aspects of healthcare delivery, but remain in their infancy.

NEW METHOD

We describe the development of a mobile health platform designed for daily measures of functional status in ambulatory, community dwelling subjects, including those who have Alzheimer's disease or related neurodegenerative disorders. Using Smartwatches and Smartphones we measure subject overall activity and outdoor location (to derive their lifespace). These clinically-relevant measures allow us to track a subject's functional status in their natural environment over prolonged periods of time without repeated visits to healthcare providers. Functional status metrics are integrated with medical information and caregiver reports, which are used by a caregiving team to guide referrals for physician/APRN/NP care. COMPARISON: with Existing Methods We describe the design tradeoffs involved in all aspects of our current system architecture, focusing on decisions with significant impact on system cost, performance, scalability, and user-adherence.

RESULTS

We provide real-world data from current subject enrollees demonstrating system accuracy and reliability.

CONCLUSIONS

We document real-world feasibility in a group of men and women with dementia that Smartwatches/Smartphones can provide long-term, relevant clinical data regarding individual functional status. We describe the underlying considerations of this system so that interested organizations can adapt and scale our approach to their needs. Finally, we provide a potential agenda to guide development of future systems.

Generating linear regression model to predict motor functions by use of laser range finder during TUG

PURPOSE

The purpose of this study was to investigate which spatial and temporal parameters of the Timed Up and Go (TUG) test are associated with motor function in elderly individuals.

METHODS

This study included 99 community-dwelling women aged 72.9 ± 6.3 years. Step length, step width, single support time, variability of the aforementioned parameters, gait velocity, cadence, reaction time from starting signal to first step, and minimum distance between the foot and a marker placed to 3 in front of the chair were measured using our analysis system. The 10-m walk test, five times sit-to-stand (FTSTS) test, and one-leg standing (OLS) test were used to assess motor function. Stepwise multivariate linear regression analysis was used to determine which TUG test parameters were associated with each motor function test. Finally, we calculated a predictive model for each motor function test using each regression coefficient.

RESULTS

In stepwise linear regression analysis, step length and cadence were significantly associated with the 10-m walk test, FTSTS and OLS test. Reaction time was associated with the FTSTS test, and step width was associated with the OLS test. Each predictive model showed a strong correlation with the 10-m walk test and OLS test (P < 0.01), which was not significant higher correlation than TUG test time.

CONCLUSION

We showed which TUG test parameters were associated with each motor function test. Moreover, the TUG test time regarded as the lower extremity function and mobility has strong predictive ability in each motor function test.

Application of a tri-axial accelerometry-based portable motion recorder for the quantitative assessment of hippotherapy in children and adolescents with cerebral palsy

[Purpose] This case series aims to evaluate the effects of hippotherapy on gait and balance ability of children and adolescents with cerebral palsy using quantitative parameters for physical activity. [Subjects and Methods] Three patients with gait disability as a sequela of cerebral palsy (one female and two males; age 5, 12, and 25 years old) were recruited. Participants received hippotherapy for 30 min once a week for 2 years. Gait parameters (step rate, step length, gait speed, mean acceleration, and horizontal/vertical displacement ratio) were measured using a portable motion recorder equipped with a tri-axial accelerometer attached to the waist before and after a 10-m walking test. [Results] There was a significant increase in step length between before and after a single hippotherapy session. Over the course of 2 year intervention, there was a significant increase in step rate, gait speed, step length, and mean acceleration and a significant improvement in horizontal/vertical displacement ratio. [Conclusion] The data suggest that quantitative parameters derived from a portable motion recorder can track both immediate and long-term changes in the walking ability of children and adolescents with cerebral palsy undergoing hippotherapy.

A pilot crossover study: effects of an intervention using an activity monitor with computerized game functions on physical activity and body composition

BACKGROUND

Wearing an activity monitor as a motivational tool and incorporating a behavior-based reward system or a computerized game element might have a synergistic effect on an increase in daily physical activity, thereby inducing body fat reduction. This pilot crossover study aimed to examine the effects of a short-term lifestyle intervention using an activity monitor with computerized game functions on physical activity and body composition.

METHODS

Twenty healthy volunteers (31 ± 3 years) participated in a 12-week crossover study. The participants were randomly assigned to either Group A (a 6-week game intervention followed by a 6-week normal intervention) or Group B (a 6-week normal intervention followed by a 6-week game intervention). The participants wore both a normal activity monitor (Lifecorder EX) and an activity monitor with computerized game functions (Yuuhokei) during the game intervention, whereas they only wore a normal activity monitor during the normal intervention. Before, during, and after the intervention, body composition was assessed.

RESULTS

Significantly more daily steps were recorded for the game intervention than for the normal intervention (10,520 ± 562 versus 8,711 ± 523 steps/day, P < 0.01). The participants performed significantly more physical activity at an intensity of ≥ 3 metabolic equivalents (METs) in the game intervention than in the normal intervention (3.1 ± 0.2 versus 2.4 ± 0.2 METs · hour/day, P < 0.01). Although body mass and fat were significantly reduced in both periods (P < 0.01), the difference in body fat reduction was significantly greater in the game intervention than in the normal intervention (P < 0.05).

CONCLUSIONS

A short-term intervention using an activity monitor with computerized game functions increases physical activity and reduces body fat more effectively than an intervention using a standard activity monitor.

Interaction between body weight status and walking speed in steps monitoring by GT3X accelerometer

The measurement error of the step count function of the ActiGraph GT3X accelerometer was assessed at different walking speeds in 12 obese and 16 nonobese individuals. In comparison with visual verification, the accelerometer step count function measurement error was larger for obese individuals walking at low speeds (2.5 km·h(-1)). This error equated to an approximate 50% underestimation at these speeds.

Recovering physical activity missing data measured by accelerometers: a comparison of individual and group-centered recovery methods

PURPOSE

The purpose of this study was to determine which method, individual information-centered (IIC) or group information-centered (GIC), is more efficient in recovering missing physical activity (PA) data.

METHOD

A total of 2,758 Chinese children and youth aged 9 to 17 years old (1,438 boys and 1,320 girls) wore ActiGraph GT3X/GT3X+ accelerometers for 7 consecutive days. Those with no missing data (n = 900) were used to form a nonmissing sample, which, based on a semisimulation approach, was used to create a missing data set to evaluate a set of recovery methods, including 2 IIC and 22 GIC methods. Root mean square difference (RMSD), mean signed difference, and paired t test were used to determine the effectiveness of the recovery methods.

RESULTS

The smallest RMSD values, which represent the most accurate recovery, were found with: (a) GIC-Expectation-maximization (GIC-EM) regardless of gender and by age (113,957.64); (b) GIC-EM regardless of gender and age (114,367.88); (c) GIC-EM regardless of age and by gender (114,697.06); (d) GIC-EM by gender and age (116,178.34); and (e) IIC averaging of remaining days (125,851.23).

CONCLUSION

To recover 7-day PA accelerometer-determined activity missing data, we recommend using the GIC-EM and IIC approaches.

Comparison of physical activity energy expenditure in Japanese adolescents assessed by EW4800P triaxial accelerometry and the doubly labelled water method

The present study compared the accuracy of triaxial accelerometry and the doubly labelled water (DLW) method for measuring physical activity (PA) in Japanese adolescents. A total of sixty adolescents aged 12–15 years were analysed. The total energy expenditure (TEE) was measured over 7 d by the DLW method and with an EW4800P triaxial accelerometer (Panasonic Corporation). The measured (RMRm) and predicted RMR (RMRp) were 5·7 (sd 0·9) and 6·0 (sd 1·0) MJ/d, respectively. TEE measured by the DLW method and accelerometry using RMRm or RMRp were 11·0 (sd 2·6), 10·3 (sd 1·9), and 10·7 (sd 2·1) MJ/d, respectively. The PA levels (PAL) measured by the DLW method using RMRm or RMRp were 1·97 (sd 0·31) and 1·94 (sd 0·31) in subjects who exercised, and 1·85 (sd 0·27) and 1·74 (sd 0·29) in subjects who did not exercise. The percentage of body fat correlated significantly with the percentage difference between RMRmv. RMRp, TEE, PA energy expenditure (PAEE) and PAL using RMRp, and PAL using RMRm assessed by the DLW method and accelerometry. The present data showed that while accelerometry estimated TEE accurately, it did not provide the precise measurement of PAEE and PAL. The error in accelerometry was attributed to the prediction error of RMR and assessment in exercise.

Measurement of human energy expenditure, with particular reference to field studies: an historical perspective

Over the years, techniques for the study of human movement have ranged in complexity and precision from direct observation of the subject through activity diaries, questionnaires, and recordings of body movement, to the measurement of physiological responses, studies of metabolism and indirect and direct calorimetry. This article reviews developments in each of these domains. Particular reference is made to their impact upon the continuing search for valid field estimates of activity patterns and energy expenditures, as required by the applied physiologist, ergonomist, sports scientist, nutritionist and epidemiologist. Early observers sought to improve productivity in demanding employment. Direct observation and filming of workers were supplemented by monitoring of heart rates, ventilation and oxygen consumption. Such methods still find application in ergonomics and sport, but many investigators are now interested in relationships between habitual physical activity and chronic disease. Even sophisticated questionnaires still do not provide valid information on the absolute energy expenditures associated with good health. Emphasis has thus shifted to use of sophisticated pedometer/accelerometers, sometimes combining their output with GPS and other data. Some modern pedometer/accelerometers perform well in the laboratory, but show substantial systematic errors relative to laboratory reference criteria such as the metabolism of doubly labeled water when assessing the varied activities of daily life. The challenge remains to develop activity monitors that are sufficiently inexpensive for field use, yet meet required accuracy standards. Possibly, measurements of oxygen consumption by portable respirometers may soon satisfy part of this need, although a need for valid longer term monitoring will remain.