Validity of activity monitors in health and chronic disease: a systematic review

Agreement between self-reported and objectively assessed physical activity among out-of-hospital cardiac arrest survivors

BACKGROUND

Low level of physical activity is a risk factor for new cardiac events in out-of-hospital cardiac arrest (OHCA) survivors. Physical activity can be assessed by self-reporting or objectively by accelerometery.

AIM

To investigate the agreement between self-reported and objectively assessed physical activity among OHCA survivors HYPOTHESIS: Self-reported levels of physical activity will show moderate agreement with objectively assessed levels of physical activity.

METHOD

Cross-sectional study including OHCA survivors in Sweden, Denmark, and the United Kingdom. Two questions about moderate and vigorous intensity physical activity during the last week were used as self-reports. Moderate and vigorous intensity physical activity were objectively assessed with accelerometers (ActiGraph GT3X-BT) worn upon the right hip for 7 consecutive days.

RESULTS

Forty-nine of 106 OHCA survivors answered the two questions for self-reporting and had 7 valid days of accelerometer assessment. More physically active days were registered by self-report compared with accelerometery for both moderate intensity (median 5 [3:7] vs. 3 [0:5] days; p < 0.001) and vigorous intensity (1 [0:3] vs. 0 [0:0] days; p < 0.001). Correlations between self-reported and accelerometer assessed physical activity were sufficient (moderate intensity: rs  = 0.336, p = 0.018; vigorous intensity: rs  = 0.375, p = 0.008), and agreements were fair and none to slight (moderate intensity: k = 0.269, p = 0.001; vigorous intensity: k = 0.148, p = 0.015). The categorization of self-reported versus objectively assessed physical activity showed that 26% versus 65% had a low level of physical activity.

CONCLUSION

OHCA survivors reported more physically active days compared with the results of the accelerometer assessment and correlated sufficiently and agreed fairly and none to slightly.

Individually optimized estimation of energy expenditure in rescue workers using a tri-axial accelerometer and heart rate monitor

Objectives: This study aimed to provide an improved energy expenditure estimation for heavy-load physical labor using accelerometer data and heart rate (HR) measured by wearables and to support food preparation and supply management for disaster relief and rescue operations as an expedition team. Methods: To achieve an individually optimized estimation for energy expenditure, a model equation parameter was determined based on the measurements of physical activity and HR during simulated rescue operations. The metabolic equivalent of task (MET), which was measured by using a tri-axial accelerometer and individual HR, was used, where two (minimum and maximum) or three (minimum, intermediate, and maximum) representative reference points were selected for each individual model fitting. In demonstrating the applicability of our approach in a realistic situation, accelerometer-based METs and HR of 30 males were measured using the tri-axial accelerometer and wearable HR during simulated rescue operations over 2 days. Results: Data sets of 27 rescue operations (age:34.2 ± 7.5 years; body mass index (BMI):22.9 ± 1.5 kg/m2) were used for the energy expenditure estimation after excluding three rescue workers due to their activity type and insufficient HR measurement. Using the combined approach with a tri-axial accelerometer and HR, the total energy expenditure increased by 143% for two points and 133% for three points, compared with the estimated total energy expenditure using only the accelerometer-based method. Conclusion: The use of wearables provided a reasonable estimation of energy expenditure for physical workers with heavy equipment. The application of our approach to disaster relief and rescue operations can provide important insights into nutrition and healthcare management.

Movement efficiency in survivors of childhood acute lymphoblastic leukemia: a report from the St. Jude lifetime cohort study

PURPOSE

Movement efficiency, a measure of neuromuscular biomechanics, may be modified by physical activity. We aimed to assess the risk of and risk factors for low movement efficiency in survivors of childhood acute lymphoblastic leukemia (ALL).

METHODS

Participants underwent an assessment of activity energy expenditure (AEE) with actigraphy, and the gold standard doubly labeled water, where the differences between elimination rates of oxygen and hydrogen from body water are evaluated over a week. Movement efficiency was assessed using the raw residuals of a linear regression between AEEs from accelerometers and doubly labeled water. Elastic-net logistic regressions were used to identify demographic, treatment, and functional variables associated with movement efficiency.

RESULTS

The study cohort included 256 non-cancer controls and 302 ALL survivors (48% female), categorized as efficient (N = 24), normal (N = 245), or inefficient (N = 33) based on their movement efficiency. There was no difference in the odds for poor movement efficiency between survivors (n = 33, 10.9%) compared to controls (n = 23, 9.0%, odds ratio [OR]: 1.19, 95% confidence interval [CI]: 0.67, 2.10; p = 0.55). In survivors, neuropathy was associated with a higher risk of being inefficient compared to efficient (OR 4.30, 95% CI 1.03-17.96), while obesity (≥ 30 kg/m2) had a protective association (OR 0.18, 95% CI 0.04-0.87).

CONCLUSIONS

Neuropathy was associated with a higher risk of poor movement efficiency in survivors of childhood ALL.

IMPLICATIONS FOR CANCER SURVIVORS

These results further highlight impairments associated with treatment-induced neuropathy in survivors of childhood ALL.

Concurrent Validity of Four Activity Monitors in Older Adults

Sedentary behaviour (SB) and physical activity (PA) have been shown to be independent modulators of healthy ageing. We thus investigated the impact of activity monitor placement on the accuracy of detecting SB and PA in older adults, as well as a novel random forest algorithm trained on data from older persons. Four monitor types (ActiGraph wGT3X-BT, ActivPAL3c VT, GENEActiv Original, and DynaPort MM+) were simultaneously worn on five anatomical sites during ten different activities by a sample of twenty older adults (70.0 (12.0) years; 10 women). The results indicated that collecting metabolic equivalent (MET) data for 60 s provided the most representative results, minimising variability. In addition, thigh-worn monitors, including ActivPAL, Random Forest, and Sedentary Sphere-Thigh, exhibited superior performance in classifying SB, with balanced accuracies ≥ 94.2%. Other monitors, such as ActiGraph, DynaPort MM+, and GENEActiv Sedentary Sphere-Wrist, demonstrated lower performance. ActivPAL and GENEActiv Random Forest outperformed other monitors in participant-specific balanced accuracies for SB classification. Only thigh-worn monitors achieved acceptable overall balanced accuracies (≥80.0%) for SB, standing, and medium-to-vigorous PA classifications. In conclusion, it is advisable to position accelerometers on the thigh, collect MET data for ≥60 s, and ideally utilise population-specific trained algorithms.

The feasibility of an exercise intervention after robotic-assisted radical cystectomy for urinary bladder cancer, prior to the CanMoRe trial

BACKGROUND

Complications after radical cystectomy for urinary bladder cancer are common. Physical activity after surgery is thought to reduce complications. However, patients with urinary bladder cancer have low levels of physical activity, and interventions supporting physical exercise are needed. This study aimed to evaluate the feasibility of a physical exercise intervention in primary health care. One of the aims of the larger clinical trial will be to reduce complications.

METHODS

Patients with urinary bladder cancer and who were scheduled for a robotic-assisted radical cystectomy were recruited from Karolinska University Hospital, between February and May 2019. The patients had to be mobile, understand Swedish, and live in Stockholm. The exercise programme was conducted at one primary health care setting over 12 weeks. The exercise programme included supervised aerobic and strengthening exercises, which were performed twice a week, as well as daily walks. Feasibility was measured with process feasibility, including eligibility criteria, adherence, and acceptability, and scientific feasibility, including the ability of outcomes to indicate change, safety, and progression in the exercise programme.

RESULTS

Ten patients with a median age of 70 years (min 53-max 86) were included. Adherence to all parts of the intervention was not feasible because of patients' postoperative complications, resulting in dropouts. For the patients who took part in the exercise programme, adherence and acceptability for the exercise period were feasible, but the 6-min walk test was not feasible at discharge from the hospital. Physiotherapists in the primary health care setting perceived the process as feasible. Moreover, the ability of outcomes to indicate change and progression in the exercise programme was feasible, meanwhile no adverse events were registered.

CONCLUSIONS

The exercise intervention was feasible for the patients that took part in the exercise programme, with respect to safety and progression through the exercise programme. Furthermore, this study suggests that some improvements needed to be implemented in the process, prior to the upcoming randomised controlled trial.

Leveraging Emerging Technologies to Expand Accessibility and Improve Precision in Rehabilitation and Exercise for People with Disabilities

Physical rehabilitation and exercise training have emerged as promising solutions for improving health, restoring function, and preserving quality of life in populations that face disparate health challenges related to disability. Despite the immense potential for rehabilitation and exercise to help people with disabilities live longer, healthier, and more independent lives, people with disabilities can experience physical, psychosocial, environmental, and economic barriers that limit their ability to participate in rehabilitation, exercise, and other physical activities. Together, these barriers contribute to health inequities in people with disabilities, by disproportionately limiting their ability to participate in health-promoting physical activities, relative to people without disabilities. Therefore, there is great need for research and innovation focusing on the development of strategies to expand accessibility and promote participation in rehabilitation and exercise programs for people with disabilities. Here, we discuss how cutting-edge technologies related to telecommunications, wearables, virtual and augmented reality, artificial intelligence, and cloud computing are providing new opportunities to improve accessibility in rehabilitation and exercise for people with disabilities. In addition, we highlight new frontiers in digital health technology and emerging lines of scientific research that will shape the future of precision care strategies for people with disabilities.

Accelerometer Use to Measure Physical Activity in Older Adults With Coronary Artery Disease: An Integrative Review

BACKGROUND

Physical activity is necessary for improved health outcomes among older adults with coronary artery disease (CAD), and device-based assessment of physical activity is preferred for accurate measurement. Many previous studies have applied accelerometry to examine physical activity in this population, but no reviews have systematically examined the application of various accelerometers to measure physical activity in older adults with CAD.

OBJECTIVE

This integrative review aimed to examine accelerometry application to measure physical activity in older adults with CAD and provide guidance for accelerometer selection and settings.

METHODS

Six databases-CINAHL, PubMed, PsycINFO, Scopus, EMBASE, and Google Scholar-were searched for information sources. Authors of selected studies applied accelerometers to measure physical activity and included adults 60 years or older with CAD.

RESULTS

Among 12 studies reviewed, 5 were randomized controlled trials, and most used an age cutoff of 65 years for older adults. The most frequently used accelerometer was the RT3, and the most common device placement was the waist/hip. Data collection duration was typically 3 consecutive days. However, many study authors did not report epoch length, sampling frequency, number of valid hours of data required per day, total number of valid days of data needed, or criteria for nonwear time.

CONCLUSIONS

On the basis of data synthesis and previous study results, triaxial research-grade accelerometers, waist/hip placement, and a 5- to 7-day monitoring period are recommended for measuring physical activity in older adults with CAD. However, the study purpose, device and participant characteristics, and physical activity outcomes of interest should be considered during device selection.

Measuring objective physical activity in people with chronic low back pain using accelerometers: a scoping review

Purpose

Accelerometers can be used to objectively measure physical activity. They could be offered to people with chronic low back pain (CLBP) who are encouraged to maintain an active lifestyle. The aim of this study was to examine the use of accelerometers in studies of people with CLBP and to synthesize the main results regarding the measurement of objective physical activity.

Methods

A scoping review was conducted following Arksey and O'Malley's framework. Relevant studies were collected from 4 electronic databases (PubMed, Embase, CINHAL, Web of Science) between January 2000 and July 2023. Two reviewers independently screened all studies and extracted data.

Results

40 publications out of 810 citations were included for analysis. The use of accelerometers in people with CLBP differed across studies; the duration of measurement, physical activity outcomes and models varied, and several limitations of accelerometry were reported. The main results of objective physical activity measures varied and were sometimes contradictory. Thus, they question the validity of measurement methods and provide the opportunity to discuss the objective physical activity of people with CLBP.

Conclusions

Accelerometers have the potential to monitor physical performance in people with CLBP; however, important technical limitations must be overcome.

Cultural adaptation and validation of the Brazilian Portuguese version of the PROactive Physical Activity in COPD-clinical visit instrument for individuals with COPD

OBJECTIVE

To adapt the PROactive Physical Activity in COPD-clinical visit (C-PPAC) instrument to the cultural setting in Brazil and to determine the criterion validity, test-retest reliability agreement, and internal consistency of this version.

METHODS

A protocol for cultural adaptation and validation was provided by the authors of the original instrument and, together with another guideline, was applied in a Portuguese-language version developed by a partner research group from Portugal. The adapted Brazilian Portuguese version was then cross-sectionally administered twice within a seven-day interval to 30 individuals with COPD (57% were men; mean age was 69 ± 6 years; and mean FEV1 was 53 ± 18% of predicted) to evaluate internal consistency and test-retest reliability. Participants also completed the International Physical Activity Questionnaire (IPAQ), the modified Medical Research Council scale, the COPD Assessment Test, and Saint George's Respiratory Questionnaire to evaluate criterion validity.

RESULTS

The C-PPAC instrument showed good internal consistency and excellent test-retest reliability: "amount" domain = 0.87 (95% CI, 0.73-0.94) and "difficulty" domain = 0.90 (95% CI, 0.76-0.96). Bland & Altman plots, together with high Lin's concordance correlation coefficients, reinforced that agreement. Criterion validity showed moderate-to-strong correlations of the C-PPAC with all of the other instruments evaluated, especially with the IPAQ (rho = -0.63).

CONCLUSIONS

The Brazilian Portuguese version of the C-PPAC is a reliable and valid instrument for evaluating the experience of Brazilian individuals with COPD with their physical activity in daily life.

Test-Retest Reliability, Agreement and Criterion Validity of Three Questionnaires for the Assessment of Physical Activity and Sedentary Time in Patients with Myocardial Infarction

Regular physical activity (PA) and limited sedentary time (SED) are highly recommended in international guidelines for patients after a myocardial infarction (MI). Data on PA and SED are often self-reported in clinical practice and, hence, reliable and valid questionnaires are crucial. This study aimed to assess the test-retest reliability, criterion validity and agreement of two PA and one SED questionnaire commonly used in clinical practice, developed by the Swedish National Board of Health and Welfare (BHW) and the Swedish national quality register SWEDEHEART. Data from 57 patients (mean age 66 ± 9.2 years, 42 males) was included in this multi-centre study. The patients answered three questionnaires on PA and SED at seven-day intervals and wore an accelerometer for seven days. Test-retest reliability, criterion validity and agreement were assessed using Spearman's rho and linearly weighted kappa. Test-retest reliability was moderate for three of the six-sub questions (k = 0.43-0.54) within the PA questionnaires. For criterion validity, the correlation was fair within three of the six sub-questions (r = 0.41-0.50) within the PA questionnaires. The SED questionnaire had low agreement (k = 0.12) and criterion validity (r = 0.30). The studied questionnaires for PA could be used in clinical practice as a screening tool and/or to evaluate the level of PA in patients with an MI. Future research is recommended to develop and/or evaluate SED questionnaires in patients with an MI.

Compensatory movement detection by using near-infrared spectroscopy technology based on signal improvement method

Introduction

Compensatory movements usually occur in stroke survivors with hemiplegia, which is detrimental to recovery. This paper proposes a compensatory movement detection method based on near-infrared spectroscopy (NIRS) technology and verifies its feasibility using a machine learning algorithm. We present a differential-based signal improvement (DBSI) method to enhance NIRS signal quality and discuss its effect on improving detection performance.

Method

Ten healthy subjects and six stroke survivors performed three common rehabilitation training tasks while the activation of six trunk muscles was recorded using NIRS sensors. After data preprocessing, DBSI was applied to the NIRS signals, and two time-domain features (mean and variance) were extracted. An SVM algorithm was used to test the effect of the NIRS signal on compensatory behavior detection.

Results

Classification results show that NIRS signals have good performance in compensatory detection, with accuracy rates of 97.76% in healthy subjects and 97.95% in stroke survivors. After using the DBSI method, the accuracy improved to 98.52% and 99.47%, respectively.

Discussion

Compared with other compensatory motion detection methods, our proposed method based on NIRS technology has better classification performance. The study highlights the potential of NIRS technology for improving stroke rehabilitation and warrants further investigation.

Assessing Physical Activity Levels among Chinese College Students by BMI, HR, and Multi-Sensor Activity Monitors

We investigated the use of multi-sensor physical activity monitors, body mass index (BMI), and heart rate (HR) to measure energy expenditure (EE) of various physical activity levels among Chinese collegiate students, compared with portable indirect calorimetry.

METHODS

In a laboratory experiment, 100 college students, 18-25 years old, wore the SenseWear Pro3 Armband™ (SWA; BodyMedia, Inc., Pittsburg, PA, USA) and performed 7 different physical activities. EE was measured by indirect calorimetry, while body motion and accelerations were measured with an SWA accelerometer. Special attention was paid to the analysis of unidirectional and three-directional accelerometer output.

RESULTS

Seven physical activities were recorded and distinguished by SWA, and different physical activities demonstrated different data features. The mean values of acceleration ACz (longitudinal accel point, axis Z) and VM (vector magnitude) were significantly different (p = 0.000, p < 0.05) for different physical activities, whereas no significant difference was found in one single physical activity with varied speeds (p = 0.9486, p > 0.05). When all physical activities were included in a correlation regression analysis, a strong linear correlation between the EE and accelerometer reporting value was found. According to the correlation analysis, sex, BMI, HR, ACz, and VM were independent variables, and the EE algorithm model demonstrated a high correlation coefficient R² value of 0.7.

CONCLUSIONS

The predictive energy consumption model of physical activity based on multi-sensor physical activity monitors, BMI, and HR demonstrated high accuracy and can be applied to daily physical activity monitoring among Chinese collegiate students.

Wearable Device Validity in Measuring Steps, Energy Expenditure, and Heart Rate Across Age, Gender, and Body Mass Index: Data Analysis From a Systematic Review

BACKGROUND

This paper examined whether the criterion validity of step count (SC), energy expenditure (EE), and heart rate (HR) varied across studies depending on the average age, body mass index (BMI), and predominant gender of participants.

METHODS

Data from 1536 studies examining the validity of various wearable devices were used. Separate multilevel regression models examined the associations among age, gender, and BMI with device criterion validity assessed using mean absolute percent error (MAPE) at the study level.

RESULTS

MAPE values were reported in 970 studies for SC, 328 for EE, and 238 for HR, respectively. There were several significant differences in MAPE between age, gender, and BMI categories for SC, EE, and HR. SC MAPE was significantly different for older adults compared with adults. Compared with studies among normal-weight populations, MAPE was greater among studies with overweight samples for SC, HR, and EE. Comparing studies with more women than men, MAPE was significantly greater for EE and HR.

CONCLUSIONS

There are important differences in the criterion validity of commercial wearable devices across studies of varying ages, BMIs, and genders. Few studies have examined differences in error between different age groups, particularly for EE and HR.

Test-retest reliability, agreement and construct validity of the International Physical Activity Questionnaire short-form (IPAQ-sf) in people with COPD

INTRODUCTION

This study assessed the test-retest reliability/agreement and construct validity of the International Physical Activity Questionnaire short-form (IPAQ-sf) in patients with chronic obstructive pulmonary disease (COPD). It also explored differences in its validity according to age, sex and GOLD airflow obstruction levels.

METHODS

62 participants (68 ± 8 years, 53 males, FEV₁ 51 ± 23%pred) completed the Portuguese IPAQ-sf, wore an accelerometer for 7 days and completed a second IPAQ-sf. Test-retest reliability/agreement was assessed with Intraclass Correlation Coefficient (ICC_2,1), 95% Limits of Agreement (LoA), standard error of measurement (SEM) and minimal detectable change (MDC₉₅) for continuous variables, and percentage of agreement (%agreement) for categories ("active"/"inactive"). Validity was assessed with 95% LoA and Spearman's correlations (ρ) between IPAQ-sf 2 (METs-min/week, time in vigorous [VPA], moderate PA [MPA] and walking) and accelerometry (time in MVPA, VPA, MPA and step counts) for continuous variables; %agreement, Cohen's kappa, and sensitivity specificity and±predictive values for categories. Correlations were also performed for age, sex and GOLD airflow obstruction grades.

RESULTS

Reliability was good (ICC_2,1 = 0.707) with wide LoA (-6446-6409 METs-min/week). SEM and MDC₉₅ were 1840 and 4971 METs-min/week, respectively. %agreement between the two IPAQ-sf was 84% (kappa = 0.660). Positive, moderate and significant correlations were found between IPAQ-sf and accelerometry (0.396 ≤ ρ ≤ 0.527, p < 0.001), except for VPA (p > 0.05). The strongest correlations were found in age (<65 years) and male (0.466 ≤ ρ ≤ 0.653, p < 0.05). %agreement between tools was 65% (kappa = 0.313), with high sensitivity (0.830) but low specificity (0.500).

CONCLUSIONS

The IPAQ-sf seems valid to be used in COPD but caution on its widespread use is recommended as its accuracy may be limited.

Study Protocol for the Breathe Easier Trial: A Pilot RCT of a Dyad-Based, Multiple-Behavior Intervention for Improving Physical and Emotional Health in Survivors Facing Lung Cancer

BACKGROUND

Research targeting survivors of lung cancer has yet to adequately address the management of physical deconditioning and unresolved symptoms (dyspnea, fatigue). The objective of the Breathe Easier trial is to test the feasibility and preliminary effects of a theory-based, multiple-behavior intervention (physical activity, smoking reduction for current smokers, stress management) targeting survivors of localized non-small-cell lung cancer (NSCLC, stages I-III) and their supportive partners.

METHODS

This pilot RCT will enroll 30 dyads (60 participants). Each dyad will consist of one survivor and one partner (defined as a family member or friend) Dyads will be randomized to the Intervention Group (IG) or the Attention Control Group (AC). IG members will receive the 12-week, home-based intervention based on the individual and family self-management theory, which targets improvements in self-efficacy, social support, and self-regulation. Improvement in lifestyle behaviors is a proximal outcome. Improvements in physical and emotional health are distal outcomes. Breathe Easier (IG) includes educational content written in plain language as well as breathing exercises and meditations; SMART goal setting; daily text messaging; and weekly telephone calls with trained staff. The AC program includes relevant National Institutes of Health publications plus weekly telephone chats. Members who currently smoke will also receive an evidence-based smoking cessation resource.

DISCUSSION

Breathe Easier focuses on changes in multiple behaviors in dyads coping with a diagnosis of NSCLC (stages I-III) with the overall purpose of improving physical and emotional health. Findings will provide additional evidence of the feasibility and preliminary effects of this intervention.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT05956782; This trial was registered retrospectively.

A Call for Action on Chronic Respiratory Diseases within Physical Activity Policies, Guidelines and Action Plans: Let's Move!

Global policy documents for the promotion of physical activity (PA) play an important role in the measurement, evaluation, and monitoring of population PA levels. The World Health Organisation (WHO) guidelines include, for the first time, recommendations for specific populations, including individuals living with a range of non-communicable diseases. Of note, is the absence of any chronic respiratory diseases (CRDs) within the recommendations. Globally, CRDs are highly prevalent, are attributable to significant individual and societal burdens, and are characterised by low PA. As a community, there is a need to come together to understand how to increase CRD representation within global PA policy documents, including where the evidence gaps are and how we can align with PA research in other contexts. In this commentary, the potential for synergy between evidence into the relationships between PA in CRDs globally and the relevance to current policies, guidelines and action plans on population levels of PA are discussed. Furthermore, actions and considerations for future research, including the need to harmonize and promote PA assessment (particularly in low- and middle-income countries) and encompass the synergistic influences of PA, sedentary behaviour and sleep on health outcomes in CRD populations are presented.

Discriminant Validity of a Single Clinical Question for the Screening of Inactivity in Individuals Living with COPD

Introduction

Quantifying physical activity in chronic obstructive pulmonary disease (COPD) with questionnaires and activity monitors in clinical practice is challenging. The aim of the present study was to analyse the discriminant validity of a single clinical question for the screening of inactive individuals living with COPD.

Methods

A multicentre study was carried out in stable COPD individuals both in primary and tertiary care. Patients wore the Dynaport accelerometer for 8 days and then answered 5 physical activity questions developed for the study, referring to the week in which their physical activity was monitored. Receiver operating characteristic (ROC) curve analysis with physical activity level (PAL) as the gold standard reference was used to determine the best cut-off point for each of the 5 clinical physical activity questions tested.

Results

A total of 86 COPD participants were analysed (males 68.6%; mean (SD) age 66.6 (8.5) years; FEV₁ 50.9 (17.3)% predicted; mean of 7305 (3906) steps/day). Forty-two (48.8%) participants were considered physically inactive (PAL ≤1.69). Answers to 4 out of 5 questions significantly differed in active vs inactive patients. The Kappa index and ROC curves showed that the answer to the question "On average, how many minutes per day do you walk briskly?" had the best discriminative capacity for inactivity, with an area under the curve (AUC) (95% Confidence interval (CI)) of 0.73 (0.63-0.84) and 30 min/day was identified as the best cut-off value (sensitivity (95% CI): 0.75 (0.60-0.87); specificity: 0.76 (0.61-0.88)).

Conclusion

The present results indicate that self-reported brisk walk time lower than 30 min/day may be a valid tool for the screening of inactivity in individuals living with COPD in routine care, if more detailed physical activity measures are not feasible.

Association of Accelerometer-Measured Sedentary Time and Physical Activity With Risk of Stroke Among US Adults

IMPORTANCE

The amount and intensity of physical activity required to prevent stroke are yet to be fully determined because of previous reliance on self-reporting measures. Furthermore, the association between objectively measured time spent being sedentary as an independent risk factor for stroke is unknown.

OBJECTIVE

To investigate the associations of accelerometer-measured sedentary time and physical activity of varying intensity and duration with the risk of incident stroke.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study involved participants who were enrolled in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study from February 5, 2003, to October 30, 2007. Accelerometer data were collected from 7607 Black and White adults 45 years or older in the contiguous US between May 12, 2009, and January 5, 2013. Data on other races and ethnicities were not collected for scientific and clinical reasons. By design, Black adults and residents of the southeastern US stroke belt and stroke buckle were oversampled. Data were analyzed from May 5, 2020, to November 11, 2021.

EXPOSURES

Sedentary time, light-intensity physical activity (LIPA), and moderate- to vigorous-intensity physical activity (MVPA) were measured using a hip-mounted accelerometer worn for 7 consecutive days and stratified by tertile for the analyses.

MAIN OUTCOMES AND MEASURES

Incident stroke.

RESULTS

Among 7607 participants, the mean (SD) age was 63.4 (8.5) years; 4145 participants (54.5%) were female, 2407 (31.6%) were Black, and 5200 (68.4%) were White. A total of 2523 participants (33.2%) resided in the stroke belt, and 1638 (21.5%) resided in the stroke buckle. Over a mean (SD) of 7.4 (2.5) years of follow-up, 286 incident stroke cases (244 ischemic [85.3%]) occurred. The fully adjusted hazard ratios (HRs) for incident stroke in the highest tertile compared with the lowest tertile were 0.74 (95% CI, 0.53-1.04; P = .08) for LIPA and 0.57 (95% CI, 0.38-0.84; P = .004) for MVPA. Higher sedentary time was associated with a 44% greater risk of incident stroke (HR, 1.44; 95% CI, 0.99-2.07; P = .04). When comparing the highest with the lowest tertile, mean sedentary bout duration was associated with a significantly greater risk of incident stroke (HR, 1.53; 95% CI, 1.10-2.12; P = .008). After adjustment for sedentary time, the highest tertile of unbouted MVPA (shorter bouts [1-9 minutes]) was associated with a significantly lower risk of incident stroke compared with the lowest tertile (HR, 0.62; 95% CI, 0.41-0.94; P = .02); however, bouted MVPA (longer bouts [at least 10 minutes]) was not (HR, 0.78; 95% CI, 0.53-1.15; P = .17). When expressed as continuous variables, sedentary time was positively associated with incident stroke risk (HR per 1-hour/day increase in sedentary time: 1.14; 95% CI, 1.02-1.28; P = .02), and LIPA was negatively associated with incident stroke risk (HR per 1-hour/day increase in LIPA: 0.86; 95% CI, 0.77-0.97; P = .02).

CONCLUSIONS AND RELEVANCE

In this cohort study, objectively measured LIPA, MVPA, and sedentary time were significantly and independently associated with incident stroke risk. Longer sedentary bout duration was also independently associated with an increased risk of incident stroke. These findings suggest that replacing sedentary time with LIPA, or even very short bouts of MVPA, may lower stroke risk, supporting the concept of moving more and sitting less as a beneficial stroke risk reduction strategy among adults.

ARTE index revisited: linking biomarkers of cardiometabolic health with free-living physical activity in postmenopausal women

Activity-related energy expenditure (AEE) correlates with physical activity volume; however, between-person differences in body size and walking economy (net V̇o2) can influence AEE. The ratio of total energy expenditure (TEE) and resting energy expenditure (REE) estimates physical activity level (PAL) relative to body mass, yet does not account for variance in walking economy. The activity-related time equivalent (ARTEwalk) circumvents such constraints by adjusting for individual-specific walking economy. Herein, we compared AEE, PAL, and ARTEwalk index in a cohort (n = 81) of postmenopausal women while examining possible associations with biomarkers of cardiometabolic health. Secondary analyses were performed on postmenopausal women dichotomized above/below age group 50th percentile for body fat percent. TEE was reduced by 10% for the thermogenesis of digestion wherein AEE was calculated by subtracting REE from adjusted TEE. PAL was calculated as the ratio of TEE/REE. AEE was divided by the mean net energy expenditure of nongraded walking to calculate the ARTEwalk index. Between-group differences were not detected for AEE or PAL. However, the ARTEwalk index revealed that participants with less adiposity were more physically active (258 ± 149 vs. 198 ± 115 min·day-1; P = 0.046; g = 0.46). AEE and PAL did not correlate with cardiorespiratory fitness or biomarkers of cardiometabolic health. Cardiorespiratory fitness (r = 0.32), arterial elasticity (r = 0.24), total cholesterol/HDL-c ratio (r = -0.22), and body fat% (r = -0.24) were correlated with ARTEwalk. The ARTEwalk index may offer utility in detecting possible differences in physical activity volume among postmenopausal women and appears better associated with cardiometabolic biomarkers compared with AEE or PAL.

mHealth-Supported Interventions With Potential to Address Sedentary Behavior in Older Adults: A Scoping Review

Sedentary behavior (SB) is an independent risk for negative health outcomes in older adults. Mobile health (mHealth) technology has potential to address SB in this population. This scoping review aimed to describe, synthesize, and identify gaps in literature on mHealth-supported interventions with potential to reduce sedentariness in older people. Following an iterative search of five major databases, 13 studies were included in the final review. Only three papers described SB-related factors as the primary target of intervention. mHealth-Driven components were frequently paired with nonmobile approaches and aided self-regulation of physical activity as opposed to SB. Most SB-related outcomes were not statistically significant or were inconclusive. This scoping review revealed a paucity of research applying mHealth-supported approaches to directly overcome sedentariness in older people. Protocol studies included in the review provide evidence that efforts to address this research gap continue to be made, but the need for additional high-quality research remains.

A Wearable System Composed of FBG-Based Soft Sensors for Trunk Compensatory Movements Detection in Post-Stroke Hemiplegic Patients

In this study, a novel wearable system for the identification of compensatory trunk movements (CTMs) in post-stroke hemiplegic patients is presented. The device is composed of seven soft sensing elements (SSEs) based on fiber Bragg grating (FBG) technology. Each SSE consists of a single FBG encapsulated into a flexible matrix to enhance the sensor’s robustness and improve its compliance with the human body. The FBG’s small size, light weight, multiplexing capability, and biocompatibility make the proposed wearable system suitable for multi-point measurements without any movement restriction. Firstly, its manufacturing process is presented, together with the SSEs’ mechanical characterization to strain. Results of the metrological characterization showed a linear response of each SSE in the operating range. Then, the feasibility assessment of the proposed system is described. In particular, the device’s capability of detecting CTMs was assessed on 10 healthy volunteers and eight hemiplegic patients while performing three tasks which are representative of typical everyday life actions. The wearable system showed good potential in detecting CTMs. This promising result may foster the use of the proposed device on post-stroke patients, aiming at assessing the proper course of the rehabilitation process both in clinical and domestic settings. Moreover, its use may aid in defining tailored strategies to improve post-stoke patients’ motor recovery and quality of life.

ENhAncing Lifestyle Behaviors in EndometriaL CancEr (ENABLE): A Pilot Randomized Controlled Trial

PURPOSE

Endometrial cancer is associated with the highest comorbid disease burden of any cancer. The aim of this trial was to assess the feasibility and safety of an allied health intervention during adjuvant treatment.

METHODS

A mixed-methods pilot randomized (2:1) controlled trial with concealed allocation and assessor-blinding. Eligibility criteria: adjuvant endometrial cancer treatment scheduled, disease stage I-IIIC1, ECOG 0-2 and able to perform unsupervised physical activity (PA). Participants received usual care and 8 sessions of weekly, individualized, lifestyle education (diet and PA) with behavior change and social support (intervention group), delivered predominantly by telehealth, or usual care alone. Feasibility outcomes: recruitment and consent rates, decline reasons, program acceptability, intervention adherence and retention.

RESULTS

22/44 eligible patients (50%, 95%CI: 36%, 64%) were recruited over 10 months (14 intervention, 8 usual care). The recruitment rate was 2.2 patients/month (95%CI: 1.4, 3.3). Patients who declined had too much going on (7/22, 32%) or were not interested (6/22, 27%). Mean (SD) age and BMI were 63.2 years (6.8) and 31.9 kg/m² (6.7). A majority were FIGO stage I (15/22, 68%) and received vaginal brachytherapy (14/22, 64%). Adherence was high, 11/14 (79%, 95%CI: 52%, 92%) participants attended >70% of scheduled sessions. Retention was 100% (95%CI: 85%, 100%) at 9 weeks, however completion of objective measures was impacted by COVID-19 restrictions. Telehealth and online questionnaires enabled participation. No serious adverse events occurred.

CONCLUSION

The intervention was acceptable to participants with high levels of adherence and retention. Trial findings will be used to design a future RCT.

TRIAL REGISTRATION

The trial was registered on www.anzctr.org.au (ACTRN12619000631101) 29/04/2019.

Usefulness of wearable fitness tracking devices in patients undergoing esophagectomy

BACKGROUND

Esophageal cancer surgery requires maintenance and enhancement of perioperative nutritional status and physical function to prevent postoperative complications. Therefore, awareness of the importance of preoperative patient support is increasing. This study examined the usefulness of using a diary in combination with a wearable fitness tracking device (WFT) in patients undergoing surgery for esophageal cancer.

METHODS

Ninety-four patients who underwent esophagectomy between February 2019 and April 2021 were included. Physicians, nurses, dietitians, and physical therapists provided diary-based education for the patients. In addition, a WFT was used by some patients. The perioperative outcomes of patients who used both the diary and WFT (WFT group) and those who used the diary alone (non-WFT group) were compared. In addition, propensity score matching was performed to improve comparability between the two groups.

RESULTS

After the propensity score matching, the rate of postoperative pneumonia was significantly lower in the WFT group (0% vs. 22.6%, P = 0.005). The postoperative hospital stay was shorter in the WFT group (P = 0.012). Nutritional status indices, such as the prognostic nutritional index, also improved significantly in the WFT group at 1 month after surgery (P = 0.034). The rate of diary entries was significantly higher in the WFT group (72.3% vs. 28.3%, P < 0.001).

CONCLUSION

The use of a WFT reduced the incidence of postoperative pneumonia and improved postoperative nutritional status and rates of diary entries after esophagectomy, suggesting that its use may be useful for promoting recovery after esophagectomy.

A Pilot Study Evaluating the Effects of a Technology-Based and Positive Psychological Training Intervention on Blood Pressure in African Americans With Hypertension

Behavioral interventions consolidating technology are underutilized and do not reach diverse populations such as African Americans with hypertension. This pilot study aimed to evaluate the effects of a theoretically derived, technology-based intervention in African Americans with hypertension. African Americans with hypertension (N = 18; age range 25-85; 72.22% females) were randomized to the technology-based plus positive psychological training (PPT) experimental group (n = 10) or the comparison group (n = 8) for 12 weeks. The technology-based intervention included analytic components (web-based education, self-monitoring of blood pressure [BP], and medication management using a commercially free app-Medisafe) and an emotional component (comprised of skills and behaviors directed at engaging 1 in positive activities to help build increasing healthy behaviors). The comparison group received the technology-based intervention alone. Demographic information, self-management cognitive processes, self-management behaviors, and health status outcomes were assessed. After completing the 12-week intervention, the groups did not significantly differ in health outcomes, health behavior outcomes, and technology utilization outcomes. Mean systolic BP decrease 6.02 mmHg (standard deviation [SD] = 22.75) in the comparison group and 1.1 mmHg (SD = 20.64; P = .439) in the experimental group. Diastolic BP decreased 0.1 mmHg (SD = 11.78) in the comparison group and 1.5 mmHg (SD = 12.7; P = .757) in the experimental group. Our findings suggest that behavioral interventions using technology have the potential to improve self-management outcomes among African American populations. Further research is warranted in a larger sample size and a longer time frame to identify the intervention’s effectiveness.

Phenotyping Adopters of Mobile Applications Among Patients With COPD: A Cross-Sectional Study

Effectiveness of technology-based interventions to improve physical activity (PA) in people with COPD is controversial. Mixed results may be due to participants' characteristics influencing their use of and engagement with mobile health apps. This study compared demographic, clinical, physical and PA characteristics of patients with COPD using and not using mobile apps in daily life. Patients with COPD who used smartphones were asked about their sociodemographic and clinic characteristics, PA habits and use of mobile apps (general and PA-related). Participants performed a six-minute walk test (6MWT), gait speed test and wore an accelerometer for 7 days. Data were compared between participants using (App Users) and not using (Non-App Users) mobile apps. A sub-analysis was conducted comparing characteristics of PA–App Users and Non-Users. 59 participants were enrolled (73% Male; 66.3 ± 8.3 yrs; FEV1 48.7 ± 18.4% predicted): 59% were App Users and 25% were PA-App Users. Significant differences between App Users and Non-App Users were found for age (64.2 ± 8.9 vs. 69.2 ± 6.3yrs), 6MWT (462.9 ± 91.7 vs. 414.9 ± 82.3 m), Gait Speed (Median 1.5 [Q1–Q3: 1.4–1.8] vs. 2.0 [1.0–1.5]m/s), Time in Vigorous PA (0.6 [0.2–2.8] vs. 0.14 [0.1–0.7]min) and Self-Reported PA (4.0 [1.0–4.0] vs. 1.0 [0.0–4.0] Points). Differences between PA–App Users and Non-Users were found in time in sedentary behavior (764.1 [641.8–819.8] vs. 672.2 [581.2–749.4] min) and self-reported PA (4.0 [2.0–6.0] vs. 2.0 [0.0–4.0] points). People with COPD using mobile apps were younger and had higher physical capacity than their peers not using mobile apps. PA-App Users spent more time in sedentary behaviors than Non-Users although self-reporting more time in PA.

Actigraphy informs distinct patient-centered outcomes in Pre-COPD

BACKGROUND

Actigraphy can provide useful patient-centered outcomes for quantification of physical activity in the "real-world" setting.

METHODS

To characterize the relationship of actigraphy outputs with "in-laboratory" measures of cardiopulmonary function and respiratory symptoms in pre-COPD, we obtained actigraphy data for 8 h/day for 5 consecutive days a week before in-laboratory administration of respiratory questionnaires, PFT, and CPET to a subgroup of subjects participating in the larger study of the health effects of exposure to secondhand tobacco smoke who had air trapping but no spirometric obstruction (pre-COPD). Using machine learning approaches, we identified the most relevant actigraphy predictors and examined their associations with symptoms, lung function, and exercise outcomes.

RESULTS

Sixty-one subjects (age = 66±7 years; BMI = 24±3 kg/m²; FEV₁/FVC = 0.75 ± 0.05; FEV₁ = 103 ± 17 %predicted) completed the nested study. In the hierarchical cluster analysis, the activity, distance, and energy domains of actigraphy, including moderate to vigorous physical activity, were closely correlated with each other, but were only loosely associated with spirometric and peak exercise measures of oxygen consumption, ventilation, oxygen-pulse, and anaerobic threshold (VO_2AT), and were divergent from symptom measures. Conversely, the sedentary domain clustered with respiratory symptoms, air trapping, airflow indices, and ventilatory efficiency. In Regression modeling, sedentary domain was inversely associated with baseline lung volumes and tidal breathing at peak exercise, while the activity domains were associated with VO_2AT. Respiratory symptoms and PFT data were not associated with actigraphy outcomes.

DISCUSSION

Outpatient actigraphy can provide information for "real-world" patient-centered outcomes that are not captured by standardized respiratory questionnaires, lung function, or exercise testing. Actigraphy activity and sedentary domains inform of distinct outcomes.

Smartphone-Based Interventions for Physical Activity Promotion: Scoping Review of the Evidence Over the Last 10 Years

Background

Several reviews of mobile health (mHealth) physical activity (PA) interventions suggest their beneficial effects on behavior change in adolescents and adults. Owing to the ubiquitous presence of smartphones, their use in mHealth PA interventions seems obvious; nevertheless, there are gaps in the literature on the evaluation reporting processes and best practices of such interventions.

Objective

The primary objective of this review is to analyze the development and evaluation trajectory of smartphone-based mHealth PA interventions and to review systematic theory- and evidence-based practices and methods that are implemented along this trajectory. The secondary objective is to identify the range of evidence (both quantitative and qualitative) available on smartphone-based mHealth PA interventions to provide a comprehensive tabular and narrative review of the available literature in terms of its nature, features, and volume.

Methods

We conducted a scoping review of qualitative and quantitative studies examining smartphone-based PA interventions published between 2008 and 2018. In line with scoping review guidelines, studies were not rejected based on their research design or quality. This review, therefore, includes experimental and descriptive studies, as well as reviews addressing smartphone-based mHealth interventions aimed at promoting PA in all age groups (with a subanalysis conducted for adolescents). Two groups of studies were additionally included: reviews or content analyses of PA trackers and meta-analyses exploring behavior change techniques and their efficacy.

Results

Included articles (N=148) were categorized into 10 groups: commercial smartphone app content analyses, smartphone-based intervention review studies, activity tracker content analyses, activity tracker review studies, meta-analyses of PA intervention studies, smartphone-based intervention studies, qualitative formative studies, app development descriptive studies, qualitative follow-up studies, and other related articles. Only 24 articles targeted children or adolescents (age range: 5-19 years). There is no agreed evaluation framework or taxonomy to code or report smartphone-based PA interventions. Researchers did not state the coding method, used various evaluation frameworks, or used different versions of behavior change technique taxonomies. In addition, there is no consensus on the best behavior change theory or model that should be used in smartphone-based interventions for PA promotion. Commonly reported systematic practices and methods have been successfully identified. They include PA recommendations, trial designs (randomized controlled trials, experimental trials, and rapid design trials), mixed methods data collection (surveys, questionnaires, interviews, and focus group discussions), scales to assess app quality, and industry-recognized reporting guidelines.

Conclusions

Smartphone-based mHealth interventions aimed at promoting PA showed promising results for behavior change. Although there is a plethora of published studies on the adult target group, the number of studies and consequently the evidence base for adolescents is limited. Overall, the efficacy of smartphone-based mHealth PA interventions can be considerably improved through a more systematic approach of developing, reporting, and coding of the interventions.

Utility of wearable physical activity monitors in cardiovascular disease: a systematic review of 11 464 patients and recommendations for optimal use

Aims

Physical activity (PA) plays an important role in primary and secondary prevention of cardiovascular disease (CVD), functioning as a marker of disease progression and response to therapy. Real-world measurement of habitual PA is now possible through wearable activity monitors, however, their use in cardiovascular patients is not well described.

Methods and results

We performed a systematic review to summarize how wearable activity monitors have been used to measure PA in patients with CVD, with 11 464 patients included across 108 studies. Activity monitors were primarily used in the setting of cardiac rehabilitation (46, 43%). Most often, triaxial accelerometers (70, 65%) were instructed to be worn at the hip (58, 54%) for 7 days (n = 54, 50%). Thirty-nine different activity monitors were used, with a range of accelerometer specific settings for collection and reporting of activity data. Activity was reported most commonly as time spent in metabolic equivalent-defined activity levels (49, 45%), while non-wear time was defined in just 16 (15%) studies.

Conclusion

The collecting, processing, and reporting of accelerometer-related outcomes were highly heterogeneous. Most validation studies are limited to healthy young adults, while the paucity of methodological information disclosed renders interpretation of results and cross-study comparison challenging. While accelerometers are promising tools to measure real-world PA, we highlight current challenges facing their use in elderly multimorbid cardiology patients. We suggest recommendations to guide investigators using these devices in cardiovascular research. Future work is required to determine optimal methodology and consensus-based development of meaningful outcomes using raw acceleration data.

Behavioural modification interventions alongside pulmonary rehabilitation improve COPD patients' experiences of physical activity

AIMS AND OBJECTIVES

The Clinical PROactive Physical Activity in COPD (C-PPAC) instrument, combines a questionnaire assessing the domains of amount and difficulty of physical activity (PA) with activity monitor data (steps/day and vector magnitude units) to assess patients' experiences of PA. The C-PPAC instrument is responsive to pharmacological and non-pharmacological interventions and to changes in clinically relevant variables. We compared the effect of PA behavioural modification interventions alongside pulmonary rehabilitation (PR) to PR alone on the C-PPAC scores in COPD patients with low baseline PA levels.

METHODS

In this randomised controlled trial, 48 patients (means ± SD: FEV₁: 50 ± 19%, baseline steps/day: 3450 ± 2342) were assigned 1:1 to receive PR alone, twice weekly for 8 weeks, or PA behavioural modification interventions (comprising motivational interviews, monitoring and feedback using a pedometer and goal setting) alongside PR (PR + PA). The C-PPAC instrument was used to assess PA experience, including a perspective of the amount and difficulty of PA.

RESULTS

There were clinically important improvements in favour of the PR + PA interventions compared to PR alone in: 1) the C-PPAC total score (mean [95% CI] difference: 8 [4 to 12] points, p = 0.001), the difficulty (mean [95% CI] difference: 8 [3 to 13] points, p = 0.002) and the amount (mean [95% CI] difference 8 [3 to 16] points, p = 0.005) domains and 2) the CAT score (mean [95% CI] difference: -2.1 [-3.8 to -0.3] points, p = 0.025).

CONCLUSION

PA behavioural modification interventions alongside PR improve the experiences of PA in patients with advanced COPD and low baseline PA levels. (NCT03749655).

Physical activity after cardiac arrest; protocol of a sub-study in the Targeted Hypothermia versus Targeted Normothermia after Out-of-Hospital Cardiac Arrest trial (TTM2)

•

The results of this study will provide novel information about physical activity among OHCA-survivors.

•

Physical activity after a cardiac arrest is currently an important knowledge-gap.

•

The results of this study have a potential to improve support and rehabilitation for OHCA-survivors.

Aims

The primary aim of this study is to investigate whether out-of-hospital cardiac arrest (OHCA) survivors have lower levels of self-reported physical activity compared to a non-cardiac arrest (CA) control group who had acute myocardial infarction (MI). Additional aims are to explore potential predictors of physical inactivity (older age, female gender, problems with general physical function, global cognition, mental processing speed/attention, anxiety symptoms, depression symptoms, kinesiophobia, fatigue), and to investigate the relationship between self-reported and objectively measured physical activity among OHCA-survivors.

Methods

The Targeted Hypothermia versus Targeted Normothermia after Out-of-Hospital Cardiac Arrest trial (TTM2-trial) collects information regarding age, gender, self-reported physical activity, general physical function, global cognition and mental processing speed/attention at 6 months after OHCA. In this TTM2-trial cross-sectional prospective sub-study, participants at selected sites are invited to an additional follow-up meeting within 4 weeks from the main study follow-up. At this meeting, information regarding anxiety symptoms, depression symptoms, kinesiophobia and fatigue is collected. The OHCA-survivors are then provided with an objective measure of physical activity, a hip-placed accelerometer, to wear for one week, together with a training diary. At the end of the week, participants are asked to once again answer two self-reported questions regarding physical activity for that specific week. MI-controls attend a single follow-up meeting and perform the same assessments as the OHCA-survivors, except from wearing the accelerometer. We aim to include 110 OHCA-survivors and 110 MI-controls in Sweden, Denmark and the United Kingdom.

Conclusion

The results from this sub-study will provide novel information about physical activity among OHCA-survivors.

Trial registration

Registered at ClinicalTrials.gov: NCT03543332, date of registration June 1, 2018

Association of Sedentary Behavior With Cancer Mortality in Middle-aged and Older US Adults

Importance

Sedentary behavior is associated with several health outcomes, including diabetes, cardiovascular disease, and all-cause mortality. Less is known about the association between objectively measured sedentary behavior and cancer mortality, as well as the association with physical activity.

Objective

To examine the association between accelerometer-measured sedentary behavior (total volume and accrual in prolonged, uninterrupted bouts) and cancer mortality.

Design, Setting, and Participants

A prospective cohort study conducted in the contiguous US included 8002 black and white adults aged 45 years or older enrolled in the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study. The present analysis was performed from April 18, 2019, to April 21, 2020.

Exposures

Sedentary time, light-intensity physical activity (LIPA), and moderate- to vigorous-intensity physical activity (MVPA) were measured using a hip-mounted accelerometer worn for 7 consecutive days.

Main Outcomes and Measures

Cancer mortality.

Results

Of the 8002 study participants, 3668 were men (45.8%); mean (SD) age was 69.8 (8.5) years. Over a mean (SD) follow-up of 5.3 (1.5) years, 268 participants (3.3%) died of cancer. In multivariable-adjusted models, including MVPA, greater total sedentary time was associated with a greater risk of cancer mortality (tertile 2 vs tertile 1: hazard ratio [HR], 1.45; 95% CI, 1.00-2.11; tertile 3 vs tertile 1: HR, 1.52; 95% CI, 1.01-2.27). Longer sedentary bout duration was not significantly associated with greater cancer mortality risk: after adjustment for MVPA (tertile 2 vs tertile 1: HR, 1.26; 95% CI, 0.90-1.78; tertile 3 vs tertile 1: HR, 1.36; 95% CI, 0.96-1.93). Replacing 30 minutes of sedentary time with LIPA was significantly associated with an 8% (per 30 minutes: HR, 0.92; 95% CI, 0.86-0.97) lower risk of cancer mortality; MVPA was significantly associated with a 31% (per 30 minutes: HR, 0.69; 95% CI, 0.48-0.97) lower risk of cancer mortality.

Conclusions and Relevance

In this cohort study, greater sedentary time, as measured with accelerometry, appeared to be independently associated with cancer mortality risk. Replacing sedentary time with either LIPA or MVPA may be associated with a lower risk of cancer mortality. These findings suggest that the total volume of sedentary behavior is a potential cancer mortality risk factor and support the public health message that adults should sit less and move more to promote longevity.

Recommendations for determining the validity of consumer wearable and smartphone step count: expert statement and checklist of the INTERLIVE network

Consumer wearable and smartphone devices provide an accessible means to objectively measure physical activity (PA) through step counts. With the increasing proliferation of this technology, consumers, practitioners and researchers are interested in leveraging these devices as a means to track and facilitate PA behavioural change. However, while the acceptance of these devices is increasing, the validity of many consumer devices have not been rigorously and transparently evaluated. The Towards Intelligent Health and Well-Being Network of Physical Activity Assessment (INTERLIVE) is a joint European initiative of six universities and one industrial partner. The consortium was founded in 2019 and strives to develop best-practice recommendations for evaluating the validity of consumer wearables and smartphones. This expert statement presents a best-practice consumer wearable and smartphone step counter validation protocol. A two-step process was used to aggregate data and form a scientific foundation for the development of an optimal and feasible validation protocol: (1) a systematic literature review and (2) additional searches of the wider literature pertaining to factors that may introduce bias during the validation of these devices. The systematic literature review process identified 2897 potential articles, with 85 articles deemed eligible for the final dataset. From the synthesised data, we identified a set of six key domains to be considered during design and reporting of validation studies: target population, criterion measure, index measure, validation conditions, data processing and statistical analysis. Based on these six domains, a set of key variables of interest were identified and a 'basic' and 'advanced' multistage protocol for the validation of consumer wearable and smartphone step counters was developed. The INTERLIVE consortium recommends that the proposed protocol is used when considering the validation of any consumer wearable or smartphone step counter. Checklists have been provided to guide validation protocol development and reporting. The network also provide guidance for future research activities, highlighting the imminent need for the development of feasible alternative 'gold-standard' criterion measures for free-living validation. Adherence to these validation and reporting standards will help ensure methodological and reporting consistency, facilitating comparison between consumer devices. Ultimately, this will ensure that as these devices are integrated into standard medical care, consumers, practitioners, industry and researchers can use this technology safely and to its full potential.

Systematic review on the application of wearable inertial sensors to quantify everyday life motor activity in people with mobility impairments

BACKGROUND

Recent advances in wearable sensor technologies enable objective and long-term monitoring of motor activities in a patient's habitual environment. People with mobility impairments require appropriate data processing algorithms that deal with their altered movement patterns and determine clinically meaningful outcome measures. Over the years, a large variety of algorithms have been published and this review provides an overview of their outcome measures, the concepts of the algorithms, the type and placement of required sensors as well as the investigated patient populations and measurement properties.

METHODS

A systematic search was conducted in MEDLINE, EMBASE, and SCOPUS in October 2019. The search strategy was designed to identify studies that (1) involved people with mobility impairments, (2) used wearable inertial sensors, (3) provided a description of the underlying algorithm, and (4) quantified an aspect of everyday life motor activity. The two review authors independently screened the search hits for eligibility and conducted the data extraction for the narrative review.

RESULTS

Ninety-five studies were included in this review. They covered a large variety of outcome measures and algorithms which can be grouped into four categories: (1) maintaining and changing a body position, (2) walking and moving, (3) moving around using a wheelchair, and (4) activities that involve the upper extremity. The validity or reproducibility of these outcomes measures was investigated in fourteen different patient populations. Most of the studies evaluated the algorithm's accuracy to detect certain activities in unlabeled raw data. The type and placement of required sensor technologies depends on the activity and outcome measure and are thoroughly described in this review. The usability of the applied sensor setups was rarely reported.

CONCLUSION

This systematic review provides a comprehensive overview of applications of wearable inertial sensors to quantify everyday life motor activity in people with mobility impairments. It summarizes the state-of-the-art, it provides quick access to the relevant literature, and it enables the identification of gaps for the evaluation of existing and the development of new algorithms.

Assessing physical activity and function in patients with chronic kidney disease: a narrative review

Physical activity potentially improves health outcomes in patients with chronic kidney disease (CKD) and recipients of kidney transplants. Although studies have demonstrated the beneficial effects of physical activity and exercise for primary and secondary prevention of non-communicable diseases, evidence for kidney patients is limited. To enlarge this evidence, valid assessment of physical activity and exercise is essential. Furthermore, CKD is associated with a decline in physical function, which may result in severe disabilities and dependencies. Assessment of physical function may help clinicians to monitor disease progression and frailty in patients receiving dialysis. The attention on physical function and physical activity has grown and new devices have been developed and (commercially) launched on the market. Therefore the aims of this review were to summarize different measures of physical function and physical activity, provide an update on measurement instruments and discuss options for easy-to-use measurement instruments for day-to-day use by CKD patients. This review demonstrates that large variation exists in the different strategies to assess physical function and activity in clinical practice and research settings. To choose the best available method, accuracy, content, preferable outcome, necessary expertise, resources and time are important issues to consider.

The Use of Activity Trackers in Interventions for Childhood Cancer Patients and Survivors: A Systematic Review

Activity trackers have emerged as promising devices used to motivate and/or objectively monitor physical activity (PA) levels. It is unknown how activity trackers have been used in interventions for children and adolescents affected by cancer. This review aimed to investigate the effectiveness of wearable activity trackers to monitor and/or improve PA levels and health outcomes in pediatric oncology. Based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses, we conducted an electronic search of four databases (Cumulative Index to Nursing and Allied Health Literature [CINAHL], Medline, Embase, and SportDiscus) between January 2000 and March 2020. The review included PA interventions that used an activity tracker with children (≤18 years) diagnosed with cancer. We excluded studies including adult participants (>18 at time of study participation) and cross-sectional or case-report studies. Twelve studies examining 517 children and adolescent patients and survivors of pediatric cancer (age range: 4-18 years) were included. Intervention delivery ranged from 2 weeks to 12 months. Two of 12 studies reported increases in PA and 6 showed improvements in health outcomes, including aerobic fitness and negative mood. PA interventions using activity trackers within pediatric oncology are highly diverse in study design, study population, and intervention features. Preliminary data suggest that interventions using wearable activity trackers may have a positive impact on health outcomes in children and adolescents affected by cancer. Future research is needed to establish optimal intervention approaches to using activity trackers to increase PA in children affected by cancer.

Maternal prepregnancy body mass index and physical activity during pregnancy assessed by accelerometer

BACKGROUND

Maternal prepregnancy overweight and obesity increase the risk of adverse pregnancy outcomes, whereas physical activity during pregnancy has a beneficial effect on both the mother and the fetus. Limited data are available on how maternal prepregnancy overweight and obesity affect physical activity during pregnancy.

OBJECTIVE

The purpose of this study was to describe the association between prepregnancy body mass index and physical activity during pregnancy.

STUDY DESIGN

An observational prospective cohort study of 400 singleton pregnant women who were attending routine antenatal care at Aarhus University Hospital, Denmark (2010-2015), was conducted. Physical activity was assessed by an accelerometer (SenseWear Armband) for 7 days for each trimester. Participants were stratified in 3 different groups of prepregnancy body mass index: normal weight (body mass index <25 kg/m²), overweight (body mass index 25-29.9 kg/m²), and obese (body mass index ≥30 kg/m²). Physical activity was measured as the number of steps per day, metabolic equivalent of task per day, time in moderate- to vigorous-intensity physical activity (>3 metabolic equivalent of task), and time in vigorous-intensity physical activity (>6 metabolic equivalent of task). Linear regression and multilevel mixed-effects models were used to explore the association between prepregnancy body mass index and physical activity variables during pregnancy.

RESULTS

We found an inverse linear relationship between prepregnancy body mass index and both mean number of steps per day and mean metabolic equivalent of task per day (P<.001). At baseline, women with normal weight walked a median of 1214 steps per day (95% confidence interval, 576-1852) more than women who were obese (P<.05), and women who were overweight walked a median of 948 steps per day (95% confidence interval, 218-1677) more than women who were obese (P<.05). Independent of prepregnancy body mass index, all variables of physical activity decreased over the course of pregnancy (P<.05), with the greatest decrease in the third trimester.

CONCLUSION

Maternal physical activity measured by an accelerometer decreased across pregnancy independent of maternal body mass index status and was inversely associated with prepregnancy body mass index. Thus, being overweight or obese before pregnancy increased the risk of sedentary behavior during pregnancy.

The validity of activity trackers is affected by walking speed: the criterion validity of Garmin Vivosmart® HR and StepWatch™ 3 for measuring steps at various walking speeds under controlled conditions

Introduction

The use of activity trackers has increased both among private consumers and in healthcare. It is therefore relevant to consider whether a consumer-graded activity tracker is comparable to or may substitute a research-graded activity tracker, which could further increase the use of activity trackers in healthcare and rehabilitation. Such use will require knowledge of their accuracy as the clinical implications may be significant. Studies have indicated that activity trackers are not sufficiently accurate, especially at lower walking speeds. The present study seeks to inform decision makers and healthcare personnel considering implementing physical activity trackers in clinical practice. This study investigates the criterion validity of the consumer-graded Garmin Vivosmart^® HR and the research-graded StepWatch^™ 3 compared with manual step count (gold standard) at different walking speeds under controlled conditions.

Methods

Thirty participants, wearing Garmin Vivosmart^® HR at the wrist and StepWatch^™ 3 at the ankle, completed six trials on a treadmill at different walking speeds: 1.6 km/h, 2.4 km/h, 3.2 km/h, 4.0 km/h, 4.8 km/h, and 5.6 km/h. The participants were video recorded, and steps were registered by manual step count. Medians and inter-quartile ranges (IQR) were calculated for steps and differences in steps between manually counted steps and the two devices. In order to assess the clinical relevance of the tested devices, the mean absolute percentage error (MAPE) was determined at each speed. A MAPE ≤3% was considered to be clinically irrelevant. Furthermore, differences between manually counted steps and steps recorded by the two devices were presented in Bland-Altman style plots.

Results

The median of differences in steps between Garmin Vivosmart^® HR and manual step count ranged from -49.5 (IQR = 101) at 1.6 km/h to -1 (IQR = 4) at 4.0 km/h. The median of differences in steps between StepWatch^™ 3 and manual step count were 4 (IQR = 14) at 1.6 km/h and 0 (IQR = 1) at all other walking speeds. The results of the MAPE showed that differences in steps counted by Garmin Vivosmart^® HR were clinically irrelevant at walking speeds 3.2-4.8 km/h (MAPE: 0.61-1.27%) as the values were below 3%. Differences in steps counted by StepWatch^™ 3 were clinically irrelevant at walking speeds 2.4-5.6 km/h (MAPE: 0.08-0.35%).

Conclusion

Garmin Vivosmart^® HR tended to undercount steps compared with the manual step count, and StepWatch^™ 3 slightly overcounted steps compared with the manual step count. Both the consumer-graded activity tracker (Garmin Vivosmart^® HR) and the research-graded (StepWatch^™ 3) are valid in detecting steps at selected walking speeds in healthy adults under controlled conditions. However, both activity trackers miscount steps at slow walking speeds, and the consumer graded activity tracker also miscounts steps at fast walking speeds.

A pragmatic approach to the comparison of wrist-based cutpoints of physical activity intensity for the MotionWatch8 accelerometer in children

Background

A variety of wearable monitors are available for objectively assessing physical activity but there is a lack of established values for the activity intensity of MotionWatch8 (MW8) and a similar lack of studies on comparability across devices. Our study aimed to establish activity intensity cutpoints for the MW8 accelerometer in children, which are necessary to determine whether they are meeting physical activity guidelines.

Methods

Children (n = 39, ages 9–13 years) were asked to wear two different accelerometers (MW8 and ActiGraph) simultaneously on the same dominant wrist as they performed different activities designed to mimic activities of variable intensity that a child might perform in a free-living environment. Linear regression and receiver operating characteristic (ROC) curves were performed to assess sensitivity and specificity of the identified MW8 intensity cutpoints compared to established ActiGraph cutpoints.

Results

Mean values for each activity were positively correlated using the MW8 and ActiGraph monitors (r = 0.85, p<0.001). The optimal cutpoints for differentiating sedentary from light physical activity, light from moderate, and moderate from vigorous activity were ≤32 counts, ≥ 371.5 counts, and ≥ 859.5 counts per 30 seconds, respectively.

Conclusions

Our study demonstrated the ability of MW8 to discriminate different intensity activities and provided the first cutoff values for researchers using the MW8 to measure physical activity patterns among children.

Sedentary Behavior and the Use of Wearable Technology: An Editorial

Globally, we continue to face a mounting issue of obesity combined with inactivity; sedentary behaviour is independently associated with poor health outcomes including disease and mortality. As such, exploring ways to try to reduce sedentary behaviour and decrease the risk of diseases is an important area of consideration. The role of wearable technology, such as fitness trackers, to encourage and subsequently increase physical activity is relatively well documented. These devices have been successful at encouraging populations to increase daily activity levels. While time being sedentary is often correlated with physical activity participation, this is not always the case. Therefore, it may be just as important to consider the activity an individual is not doing when evaluating health and well-being. This Editorial will summarize the importance of distinguishing between physical activity and sedentary behaviour. It will also discuss how wearable technology, in the form of fitness trackers, may be used to encourage someone to break up sedentary bouts more often. Finally, we will consider important future research directions.

Online compensation detecting for real-time reduction of compensatory motions during reaching: a pilot study with stroke survivors

BACKGROUND

Compensations are commonly observed in patients with stroke when they engage in reaching without supervision; these behaviors may be detrimental to long-term functional improvement. Automatic detection and reduction of compensation cab help patients perform tasks correctly and promote better upper extremity recovery.

OBJECTIVE

Our first objective is to verify the feasibility of detecting compensation online using machine learning methods and pressure distribution data. Second objective was to investigate whether compensations of stroke survivors can be reduced by audiovisual or force feedback. The third objective was to compare the effectiveness of audiovisual and force feedback in reducing compensation.

METHODS

Eight patients with stroke performed reaching tasks while pressure distribution data were recorded. Both the offline and online recognition accuracy were investigated to assess the feasibility of applying a support vector machine (SVM) based compensation detection system. During reduction of compensation, audiovisual feedback was delivered using virtual reality technology, and force feedback was delivered through a rehabilitation robot.

RESULTS

Good classification performance was obtained in online compensation recognition, with an average F1-score of over 0.95. Based on accurate online detection, real-time feedback significantly decreased compensations of patients with stroke in comparison with no-feedback condition (p < 0.001). Meanwhile, the difference between audiovisual and force feedback was also significant (p < 0.001) and force feedback was more effective in reducing compensation in patients with stroke.

CONCLUSIONS

Accurate online recognition validated the feasibility of monitoring compensations using machine learning algorithms and pressure distribution data. Reliable online detection also paved the way for reducing compensations by providing feedback to patients with stroke. Our findings suggested that real-time feedback could be an effective approach to reducing compensatory patterns and force feedback demonstrated a more enviable potential compared with audiovisual feedback.

Translation and Cultural Adaptation of PROactive Instruments for COPD in French and Influence of Weather and Pollution on Its Difficulty Score

Introduction

The recently developed daily and clinical visit PROactive physical activity in COPD (PPAC) instruments are hybrid tools to objectively quantify the level of physical activity and the difficulties experienced in everyday life. Our aim was to translate these instruments for the French-speaking chronic obstructive pulmonary disease (COPD) community worldwide and evaluate the influence of weather and pollution on difficulty score.

Methods

The translation procedure was conducted following the guidelines for cross-cultural adaptation process. The translated clinical visit (C-PPAC) was tested among COPD patients in France. A retest was conducted after an interval of at least 2 weeks. The C-PPAC difficulty score was then tested to see how sensitive it was to the influence of weather and outdoor pollution.

Results

One hundred and seventeen COPD patients (age 65±9 years; FEV1: 51±20%) from 9 regions in France were included. The French version of C-PPAC was found comprehensible by the patients with an average score of 4.8/5 on a Likert-scale. It showed good internal consistency with Cronbach’s α>0.90 and a good test retest reliability with an intraclass correlation coefficient of ≥0.80. The difficulty score was negatively correlated with duration of daylight (ρ=−0.266; p<0.01) and influenced by the intensity of rainfall (light vs. heavy rainfall: 68±16 vs. 76±14 respectively, p=0.045). The score was lower in patients receiving long term oxygen therapy (60±15 vs. 71±15, p<0.01), but not correlated with the pollution indices.

Conclusion

The French versions of the questionnaires of the PPAC instruments are accepted and comprehensible to COPD patients. The difficulty score of C-PPAC is sensitive to duration of daylight and rainfall. Such weather factors must be taken into consideration when evaluating the physical activity behavior using these tools in COPD.

Patient-Generated Actigraphy Data as a Novel Outcomes Instrument in Carpal Tunnel Syndrome

BACKGROUND

Currently, we lack objective measures to quantify outcomes in carpal tunnel syndrome. Instead, surgeons rely on patient-reported outcomes measures (PROMs) to assess the effect of carpal tunnel release (CTR). We assessed the validity and reliability of wearable activity monitors to objectively characterize the functional and sleep impact of CTR. We hypothesized that actigraphy could detect changes in sleep and activity and would demonstrate short-term impairment due the operative procedure.

METHODS

This pilot, prospective, cohort study compared validated PROMS with actigraphy data obtained via wearable activity monitors (ActiGraph Link; ActiGraph Corp, Pensacola, Fla). Subjects completed baseline questionnaires and wore their device for 1 week preoperatively as a baseline. Subjects then underwent open CTR, wearing actigraphy devices for 4 weeks and completing questionnaires at 2 and 4 weeks postoperatively. Preintervention and postintervention data were compared using paired-sample t test. The Patient-Reported Outcomes Measurement Information System (PROMIS) questionnaire data were analyzed in accordance with published PROMIS scoring manuals and raw scores were converted to standardized T scores.

RESULTS

Twenty subjects (5 males, 15 females) with moderate or severe carpal tunnel syndrome were enrolled. The mean age was 57.7 years. The PROMIS 29 average cumulative T score was 42.9 with average change of -0.072 preoperatively versus postoperatively. Average sleep disturbance T score was 38.9 preoperatively and 41.4 postoperatively. There was no statistically significant difference in T score in any domain. The mean actigraphy activity data demonstrated near immediate return to baseline activity. Actigraphy sleep data demonstrate improvement in sleep fragmentation and decreased duration of awakenings.

CONCLUSIONS

Overall, patient-generated data detected differences in sleep and activity preoperatively versus postoperatively and demonstrated only a short period of activity disruption after CTR, which may be used when counseling patients. These data support actigraphy as a viable adjunct to traditional PROMS to evaluate the impact of surgical intervention and therefore may be useful in the study of other diseases affecting the upper extremity.

The Performance of Patient-Worn Actigraphy Devices to Measure Recovery after Breast Reconstruction

Annually, over 250,000 women are diagnosed with breast cancer with over one-third undergoing mastectomy and contemplating reconstruction. Surgical breast reconstructive options vary in post-operative recovery, yet with a paucity of objective data to inform women of their expected recovery after flap or implant-based reconstruction. As a result, patient decision-making is based primarily on surgeon preference and subjective data regarding perceived invasiveness of surgical options. This study aims to identify recovery outcomes of interest to breast cancer patients and to determine the feasibility of objectively measuring patient recovery after mastectomy and reconstruction using patient-worn actigraphy devices.

Exploring Children's Physical Activity Behaviours According to Location: A Mixed-Methods Case Study

The school environment is ideally placed to facilitate physical activity (PA) with numerous windows of opportunity from break and lunch times, to lesson times and extracurricular clubs. However, little is known about how children interact with the school environment to engage in PA and the other locations they visit daily, including time spent outside of the school environment i.e., evening and weekend locations. Moreover, there has been little research incorporating a mixed-methods approach that captures children’s voices alongside objectively tracking children’s PA patterns. The aim of this study was to explore children’s PA behaviours according to different locations. Sixty children (29 boys, 31 girls)—35 key stage 2 (aged 9–11) and 25 key stage 3 (aged 11–13)—wore an integrated global positioning systems (GPS) and heart rate (HR) monitor over four consecutive days. A subsample of children (n = 32) were invited to take part in one of six focus groups to further explore PA behaviours and identify barriers and facilitators to PA. Children also completed a PA diary. The KS2 children spent significantly more time outdoors than KS3 children (p = 0.009). Boys engaged in more light PA (LPA) when on foot and in school, compared with girls (p = 0.003). KS3 children engaged in significantly more moderate PA (MPA) at school than KS2 children (p = 0.006). Focus groups revealed fun, enjoyment, friends, and family to be associated with PA, and technology, costs, and weather to be barriers to PA. This mixed methodological study highlights differences in the PA patterns and perceptions of children according to age and gender. Future studies should utilize a multi-method approach to gain a greater insight into children’s PA patterns and inform future health policies that differentiate among a range of demographic groups of children.

Validity and Reliability of Accelerometers in Patients With COPD: A SYSTEMATIC REVIEW

PURPOSE

Reduced physical activity is associated with poor prognosis in chronic obstructive pulmonary disease (COPD). Accelerometers have greatly improved quantification of physical activity by providing information on step counts, body positions, energy expenditure, and magnitude of force. The purpose of this systematic review was to compare the validity and reliability of accelerometers used in patients with COPD.

METHODS

An electronic database search of MEDLINE and CINAHL was performed. Study quality was assessed with the Strengthening the Reporting of Observational Studies in Epidemiology checklist while methodological quality was assessed using the modified Quality Appraisal Tool for Reliability Studies.

RESULTS

The search yielded 5392 studies; 25 met inclusion criteria. The SenseWear Pro armband reported high criterion validity under controlled conditions (r = 0.75-0.93) and high reliability (ICC = 0.84-0.86) for step counts. The DynaPort MiniMod demonstrated highest concurrent validity for step count using both video and manual methods.

DISCUSSION

Validity of the SenseWear Pro armband varied between studies especially in free-living conditions, slower walking speeds, and with addition of weights during gait. A high degree of variability was found in the outcomes used and statistical analyses performed between studies, indicating a need for further studies to measure reliability and validity of accelerometers in COPD.

CONCLUSION

The SenseWear Pro armband is the most commonly used accelerometer in COPD, but measurement properties are limited by gait speed variability and assistive device use. DynaPort MiniMod and Stepwatch accelerometers demonstrated high validity in patients with COPD but lack reliability data.

Detecting compensatory movements of stroke survivors using pressure distribution data and machine learning algorithms

BACKGROUND

Compensatory movements are commonly employed by stroke survivors during seated reaching and may have negative effects on their long-term recovery. Detecting compensation is useful for coaching the patient to reduce compensatory trunk movements and improving the motor function of the paretic arm. Sensor-based and camera-based systems have been developed to detect compensatory movements, but they still have some limitations, such as causing object obstructions, requiring complex setups and raising privacy concerns. To overcome these drawbacks, this paper proposes a compensatory movement detection system based on pressure distribution data and is unobtrusive, simple and practical. Machine learning algorithms were applied to classify compensatory movements automatically. Therefore, the purpose of this study was to develop and test a pressure distribution-based system for the automatic detection of compensation movements of stroke survivors using machine learning algorithms.

METHODS

Eight stroke survivors performed three types of reaching tasks (back-and-forth, side-to-side, and up-and-down reaching tasks) with both the healthy side and the affected side. The pressure distribution data were recorded, and five features were extracted for classification. The k-nearest neighbor (k-NN) and support vector machine (SVM) algorithms were applied to detect and categorize the compensatory movements. The surface electromyography (sEMG) signals of nine trunk muscles were acquired to provide a detailed description and explanation of compensatory movements.

RESULTS

Cross-validation yielded high classification accuracies (F1-score>0.95) for both the k-NN and SVM classifiers in detecting compensation movements during all the reaching tasks. In detail, an excellent performance was achieved in discriminating between compensation and noncompensation (NC) movements, with an average F1-score of 0.993. For the multiclass classification of compensatory movement patterns, an average F1-score of 0.981 was achieved in recognizing the NC, trunk lean-forward (TLF), trunk rotation (TR) and shoulder elevation (SE) movements.

CONCLUSIONS

Good classification performance in detecting and categorizing compensatory movements validated the feasibility of the proposed pressure distribution-based system. Reliable classification accuracy achieved by the machine learning algorithms indicated the potential to monitor compensation movements automatically by using the pressure distribution-based system when stroke survivors perform seated reaching tasks.