Accuracy of a smartphone pedometer application according to different speeds and mobile phone locations in a laboratory context

Reducing sedentary behavior improves depressive symptoms among patients with heart failure enrolled in a home-based mobile health app cardiac rehabilitation

BACKGROUND

Depressive symptoms are common, worsening heart failure (HF) progression and reducing quality of life. While supervised structured exercise training is effective for managing depressive symptoms, it often demands a substantial time commitment or intensive activity that may discourage participation.

OBJECTIVE

Evaluate the impacts of reducing sedentary time with short bouts of light physical activities or greater intensity levels on depressive symptoms after HF patients' enrollment in a home-based intervention.

METHODS

A total of 127 HF patients participated in an experimental two-group design, randomly allocated to either delayed or immediate decreasing sedentary time intervention. The immediate group started the intervention immediately, while the delayed group began after the first group finished their intervention. The 8-week intervention, guided by the Theory of Planned Behavior, focused on interrupting 30 min of sedentary behavior with short bouts of light- or greater intensity physical activities. Demographic and clinical variables were collected at baseline. Depressive symptoms were assessed at baseline, pre-intervention, and post-intervention. Physical activity (daily steps) was monitored daily during the study period using the Samsung mobile health app.

RESULTS

Both groups demonstrated reduced sedentary time during the intervention, with improvements in HF symptom burden. Repeated measures analysis of variance revealed a significant reduction in depressive symptoms in both groups post-intervention, with a greater reduction seen in the immediate group before the delayed group began the intervention.

CONCLUSION

The study highlights the effectiveness of interrupting sedentary behavior with light- or greater intensity activities in managing depressive symptoms among HF patients. The home-based intervention, facilitated by mobile technology, provides a feasible and accessible approach to improving mental well-being.

CLINICAL RELEVANCE

The findings support the broader implementation of home-based interventions addressing sedentary time reduction as a valuable strategy for enhancing the mental health of HF patients, particularly those facing challenges with traditional rehabilitation programs or intense exercise.

Apple Watch 6 vs. Galaxy Watch 4: A Validity Study of Step-Count Estimation in Daily Activities

The purpose of this study was to examine the validity of two wearable smartwatches (the Apple Watch 6 (AW) and the Galaxy Watch 4 (GW)) and smartphone applications (Apple Health for iPhone mobiles and Samsung Health for Android mobiles) for estimating step counts in daily life. A total of 104 healthy adults (36 AW, 25 GW, and 43 smartphone application users) were engaged in daily activities for 24 h while wearing an ActivPAL accelerometer on the thigh and a smartwatch on the wrist. The validities of the smartwatch and smartphone estimates of step counts were evaluated relative to criterion values obtained from an ActivPAL accelerometer. The strongest relationship between the ActivPAL accelerometer and the devices was found for the AW (r = 0.99, p < 0.001), followed by the GW (r = 0.82, p < 0.001), and the smartphone applications (r = 0.93, p < 0.001). For overall group comparisons, the MAPE (Mean Absolute Percentage Error) values (computed as the average absolute value of the group-level errors) were 6.4%, 10.5%, and 29.6% for the AW, GW, and smartphone applications, respectively. The results of the present study indicate that the AW and GW showed strong validity in measuring steps, while the smartphone applications did not provide reliable step counts in free-living conditions.

Associations between changes of smartphone pedometer-assessed step counts and levels of obesity-related breast cancer biomarkers in non-cancer women: A population-based observational study

While a higher level of physical activity (PA) is inversely associated with a higher breast cancer (BC) risk, the health benefits of daily steps on obesity-related BC biomarkers remain unclear. We aimed to understand the associations of changes in step counts with levels of five obesity-related BC biomarkers during a two-year follow-up. In total, 144 non-cancer women (47.96 ± 5.72) were observed on both 2019 and 2021. A structured questionnaire, daily steps and fasting blood samples were collected before (t0, 2019) and after (t1, 2021). Levels of biomarkers (IGF-binding proteins 3, adiponectin, soluble leptin receptor, C-reactive protein, and resistin) were assayed by ELISA. Participants were divided into persistent low steps, decreasing steps, increasing steps, and persistent high steps. Associations of categories on proposed biomarkers were estimated using linear regression models, with persistent low steps as reference. Associations between time-varying step counts with biomarkers were quantified using mixed linear models. Compared with persistent low steps, increasing steps is associated with a reduction in C-reactive protein level (β=-0.74, 95%CI=-1.23--0.26, P-value = 2.98 × 10-3). An inverse association between time-varying step counts with C-reactive protein level was identified, consistent across different obesity types and baseline step level categories. No association with daily step counts was observed for other proteins.

Effects of a Mobilization Program Applied to Bariatric Surgery Patients on Preventing Gastrointestinal Complications: a Quasi-Experimental Study

PURPOSE

To investigate the effects of a planned early targeted mobilization program applied to patients that underwent bariatric surgery with the laparoscopic sleeve gastrectomy method on gastrointestinal complications (nausea-vomiting, abdominal distention, delayed flatus-defecation, and intolerance of early oral intake).

MATERIALS AND METHODS

This prospective, controlled group, quasi-experimental design study was conducted between July 2019 and March 2020 in the general surgery clinic of a training and research hospital with 70 patients who underwent sleeve gastrectomy and met the inclusion criteria. The prepared mobilization program was applied to the patients on the 0th, 1st, and 2nd postoperative days, and the gastrointestinal functions of the patients were monitored.

RESULTS

The intervention group had a significantly shorter time to first flatus, defecation, and oral intake; higher frequency of defecation; lower pain, abdominal distention, and nausea; better tolerance of oral intake; and higher total oral intake compared to the control group (p < 0.05).

CONCLUSION

Planned, early, and targeted mobilization was determined to be a feasible, safe, and cost-effective nursing intervention to prevent gastrointestinal complications in patients undergoing sleeve gastrectomy.

Predictors of physical activity behavior change among patients with heart failure enrolled in home-based cardiac rehabilitation intervention

BACKGROUND

Physical activity behavior change is considered one of the most challenging lifestyle modifications in patients with heart failure. Even after participation in a cardiac rehabilitation program, most patients do not engage in the recommended level of physical activity.

OBJECTIVE

To determine which baseline demographic, physical activity levels, psychological distress, and clinical variables predicted physical activity behavior change to increasing light-to-vigorous physical activity by 10,000 steps/day following participation in home-based cardiac rehabilitation intervention.

METHODS

A prospective design involving secondary analysis was used to analyze data obtained from 127 patients (mean, 61; range, 45-69 years) enrolled in and completed an 8-week home-based mobile health app intervention. The intervention was designed to encourage health behavior change with regard to decreasing sedentary behavior and increasing physical activities performed at light or greater intensities.

RESULTS

None of the participants accumulated 10,000 steps or more per day pre-intervention (mean, 1549; range, 318-4915 steps/day). Only 55 participants (43%) achieved an average daily step count of 10,000 or more at week 8 of the intervention (10,674 ± 263). The results of the logistic regression showed that higher pre-intervention physical activity levels and anxiety symptoms and lower depressive symptoms were associated with a higher likelihood of achieving physical activity behavior change (p < .003).

CONCLUSION

These data highlight that determining pre-intervention physical activity levels and depressive symptoms can be the key to designing an effective home-based cardiac rehabilitation intervention in patients with heart failure.

Let's Move with Leon. A randomised controlled trial of a UK digital intervention to improve physical activity in people with a musculoskeletal condition

OBJECTIVE

This article presents a real-world evaluation of a digital intervention, 'Let's Move with Leon', designed to improve physical activity and health-related quality of life (HRQoL) in people with a musculoskeletal condition.

STUDY DESIGN

A pragmatic randomised controlled trial.

METHODS

After randomisation and withdrawals were removed, 184 participants were assigned to receive the digital intervention with 185 assigned to a control group. Self-reported physical activity was the primary outcome. Health-related quality of life, the number of days completing strength-based exercises per week, the capability, opportunity, and motivation to be active, and step count were secondary outcomes. Outcomes were assessed over 4, 8 and 13 weeks.

RESULTS

Significant improvements were seen for self-reported physical activity at 13 weeks, reported strength days at 8 weeks, perceptions of physical capability and automatic motivation to be active at 4 and 8 weeks. No improvements were seen in step count or HRQoL over the control group.

CONCLUSION

Digital interventions such as 'Let's Move with Leon' have the potential to increase physical activity in people with a musculoskeletal condition; however, improvements are likely to be small. Small improvements in physical activity may not be enough to improve HRQoL.

Effect of a Home-Based Mobile Health App Intervention on Physical Activity Levels in Patients With Heart Failure: A Randomized Controlled Trial

BACKGROUND

The use of mobile health applications (apps) is an effective strategy in supporting patients' self-management of heart failure (HF) in home settings, but it remains unclear whether they can be used to reduce sedentary behaviors and increase overall physical activity levels.

AIM

The aims of this study were to determine the effect of an 8-week home-based mobile health app intervention on physical activity levels and to assess its effects on symptom burden and health-related quality of life.

METHOD

In this study, we collected repeated-measures data from 132 participants with HF (60.8 ± 10.47 years) randomized into a usual care group (n = 67) or an 8-week home-based mobile health app intervention group (n = 65). The intervention was tailored to decrease the time spent in sedentary behavior and to increase the time spent in physical activities performed at light or greater intensity levels. Physical activity levels were monitored for 2 weeks before the intervention and during the 8-week intervention using the Samsung mobile health app. Heart failure symptom burden and health-related quality of life were assessed at baseline, 2 weeks from baseline assessment, and immediately post intervention.

RESULTS

At week 8, all participants in the intervention group demonstrated an increase in the average daily step counts above the preintervention counts (range of increase: 2351-7925 steps/d). Only 29 participants (45%) achieved an average daily step count of 10 000 or higher by week 6 and maintained their achievement to week 8 of the intervention. Repeated-measures analysis of variance showed a significant group-by-time interaction, indicating that the intervention group had a greater improvement in physical activity levels, symptom burden, and health-related quality of life than the usual care group.

CONCLUSION

Home-based mobile health app-based interventions can increase physical activity levels and can play an important role in promoting better HF outcomes.

Subjective and Behavioral Impulsivity Differentially Moderate Within- and Between-Person Associations Between Physical Activity and Alcohol Consumption

OBJECTIVE

Evidence indicates a counterintuitive positive relationship between physical activity and alcohol consumption, suggesting that people who engage in more physical activity consume more alcohol. Impulsivity, which has a well-documented role in alcohol use disorders, has been shown to moderate the between-person physical activity-drinking association among emerging adults. However, only a handful of studies have explored within-person associations of physical activity and drinking and potential moderators of this relationship. The current study evaluated the effects of both subjective and behavioral impulsivity on the within- and between-person association between physical activity and alcohol consumption among college students.

METHOD

Undergraduate students (N = 250) between ages 18 and 25 years were asked to report their daily physical activity and drinking over 21 days. Physical activity was also recorded objectively through Pacer, a smartphone app. Subjective impulsivity was assessed using the UPPS-P Impulsive Behavior Scale, and behavioral impulsivity was evaluated using the Balloon Analogue Risk Task.

RESULTS

Within- and between-subject physical activity-drinking associations were differentially moderated by behavioral impulsivity and self-reported impulsivity. For instance, behavioral impulsivity moderated the within-person association between drinking and self-reported vigorous physical activity, whereas negative urgency moderated the between-person association between drinking and objective physical activity.

CONCLUSIONS

Impulsivity, whether measured subjectively or behaviorally, significantly moderates the physical activity-alcohol consumption association. Importantly, this effect operates differently when predicting variation in behavior within individuals as compared with predicting differences in behavior between individuals.

Adherence and retention to the self-managed community-based Step Into Health program in Qatar (2012-2019)

Purpose

Investigate adherence and retention to the "Step Into Health (SIH)" initiative (www.stepintohealth.qa [website access only available from within the State of Qatar]), a Qatari self-managed community-based health program, from 2012 to 2019.

Methods

Participants (16,711; 16-80 years; 37% females, 34% Qatari) used a pedometer or smartphone application (app) to measure step count. Absolute adherence (ADH) and retention (RET) were calculated, with ADH (%) the ratio between number of days data and SIH enrollment length (RET). Linear Mixed Models identified differences in ADH between RET groups, main effects (i.e., sex, device, age, BMI, nationality) and interaction effects for ADH (RET entered as a covariate).

Results

Average ADH and RET to SIH (irrespective of sex, age, device and BMI) was 50% (±31%), and 16% (±20%), respectively, with ADH differing significantly between RET groups (F = 460.2, p < 0.001). RET (as a covariate) revealed a significant main effect for device (F = 12.00, p < 0.001) and age (F = 4.31, p = 0.001) on ADH observed. There was a significant association between RET and sex (p < 0.001), device (p < 0.001), and age groups 16-25 y (p < 0.001), and 26-35 y (p < 0.001). There were no significant main effects for sex or BMI on ADH, and no interaction effects (p ≥ 0.21) observed.

Conclusions

Follow-up data (e.g., interviews, focus groups, etc.) determining why differences in ADH and RET are observed appears prudent. To convert those that lapsed and/or abandoned SIH/PA into committed long-term PA adherers. This would be a first step to develop targeted public health promotions and initiatives to enhance health outcomes at a population level.

The effect of temperature on physical activity: an aggregated timeseries analysis of smartphone users in five major Chinese cities

Background

Physical activity is an important factor in premature mortality reduction, non-communicable disease prevention, and well-being protection. Climate change will alter temperatures globally, with impacts already found on mortality and morbidity. While uncomfortable temperature is often perceived as a barrier to physical activity, the actual impact of temperature on physical activity has been less well studied, particularly in China. This study examined the associations between temperature and objectively measured physical activity among adult populations in five major Chinese cities.

Methods

Aggregated anonymized step count data was obtained between December 2017-2018 for five major Chinese cities: Beijing, Shanghai, Chongqing, Shenzhen, and Hong Kong. The associations of temperature with daily aggregated mean step count were assessed using Generalized Additive Models (GAMs), adjusted for meteorological, air pollution, and time-related variables.

Results

Significant decreases in step counts during periods of high temperatures were found for cold or temperate climate cities (Beijing, Shanghai, and Chongqing), with maximum physical activity occurring between 16 and 19.3 °C. High temperatures were associated with decreases of 800-1500 daily steps compared to optimal temperatures. For cities in subtropical climates (Shenzhen and Hong Kong), non-significant declines were found with high temperatures. Overall, females and the elderly demonstrated lower optimal temperatures for physical activity and larger decreases of step count in warmer temperatures.

Conclusions

As minor reductions in physical activity could consequentially affect health, an increased awareness of temperature’s impact on physical activity is necessary. City-wide adaptations and physical activity interventions should seek ways to sustain physical activity levels in the face of shifting temperatures from climate change.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12966-022-01285-1.

The Mézières Method as a Novel Treatment for Elite Spanish Second-Division Soccer League Players With Low Back Pain: A Randomized Controlled Trial

OBJECTIVES

To evaluate the efficacy of 24 weeks of treatment with Mézières method in a Spanish elite second-division soccer team with low back pain (LBP), analyzing their state of back health, flexibility, pain, and steps speed.

DESIGN

Double-blind randomized controlled trial.

METHODS

A total of 20 players with LBP from the second soccer division league were allocated equally to the experimental and control groups (n = 10) as per selection criteria and participated in 2 different rehabilitation programs. The postural Mézières method was implemented in the experimental group, whereas the standard European treatment protocol for LBP was implemented in the control group. Both treatments had a twice weekly session of 40 minutes duration for 24 weeks consecutively with a follow-up in the fourth, 12th, and 24th weeks.

RESULTS

Multivariate analysis of covariance with the baseline assessment as a covariance showed a significant difference between groups at the 12th and 24th weeks of the treatment for pain and back functionality. A relevant difference between the experimental and control groups was shown only at the 24th week of the treatment (P < .05) for back flexibility. A significant difference between groups was reported for the quality of life scale and steps speed at the 24th week of the treatment (P > .05).

CONCLUSION

The Mézières method showed a positive effect in the elite soccer athletes with nonspecific chronic LBP and can be used as an alternative treatment.

The need for feminist intersectionality in digital health

Digital health, including the use of mobile health apps, telemedicine, and data analytics to improve health systems, has surged during the COVID-19 pandemic. The social and economic fallout from COVID-19 has further exacerbated gender inequities, through increased domestic violence against women, soaring unemployment rates in women, and increased unpaid familial care taken up by women-all factors that can worsen women's health. Digital health can bolster gender equity through increased access to health care, empowerment of one's own health data, and reduced burden of unpaid care work. Yet, digital health is rarely designed from a gender equity perspective. In this Viewpoint, we show that because of lower access and exclusion from app design, gender imbalance in digital health leadership, and harmful gender stereotypes, digital health is disadvantaging women-especially women with racial or ethnic minority backgrounds. Tackling digital health's gender inequities is more crucial than ever. We explain our feminist intersectionality framework to tackle digital health's gender inequities and provide recommendations for future research.

Adaptive learning algorithms to optimize mobile applications for behavioral health: guidelines for design decisions

OBJECTIVE

Providing behavioral health interventions via smartphones allows these interventions to be adapted to the changing behavior, preferences, and needs of individuals. This can be achieved through reinforcement learning (RL), a sub-area of machine learning. However, many challenges could affect the effectiveness of these algorithms in the real world. We provide guidelines for decision-making.

MATERIALS AND METHODS

Using thematic analysis, we describe challenges, considerations, and solutions for algorithm design decisions in a collaboration between health services researchers, clinicians, and data scientists. We use the design process of an RL algorithm for a mobile health study "DIAMANTE" for increasing physical activity in underserved patients with diabetes and depression. Over the 1.5-year project, we kept track of the research process using collaborative cloud Google Documents, Whatsapp messenger, and video teleconferencing. We discussed, categorized, and coded critical challenges. We grouped challenges to create thematic topic process domains.

RESULTS

Nine challenges emerged, which we divided into 3 major themes: 1. Choosing the model for decision-making, including appropriate contextual and reward variables; 2. Data handling/collection, such as how to deal with missing or incorrect data in real-time; 3. Weighing the algorithm performance vs effectiveness/implementation in real-world settings.

CONCLUSION

The creation of effective behavioral health interventions does not depend only on final algorithm performance. Many decisions in the real world are necessary to formulate the design of problem parameters to which an algorithm is applied. Researchers must document and evaulate these considerations and decisions before and during the intervention period, to increase transparency, accountability, and reproducibility.

TRIAL REGISTRATION

clinicaltrials.gov, NCT03490253.

Does surrounding greenness moderate the relationship between apparent temperature and physical activity? Findings from the PHENOTYPE project

BACKGROUND

Physical activity can be affected by both meteorological conditions and surrounding greenness, but few studies have evaluated the effects of these environmental factors on physical activity simultaneously. This multi-city comparative study aimed to assess the synergetic effects of apparent temperature and surrounding greenness on physical activity in four European cities. Specifically, we aimed to identify an interaction between surrounding greenness and apparent temperature in the effects on physical activity.

METHODS

Data were collected from 352 adult residents of Barcelona (Spain), Stoke-on-Trent (United Kingdom), Doetinchem (The Netherlands), and Kaunas (Lithuania) as part of the PHENOTYPE study. Participants wore a smartphone for seven consecutive days between May-December 2013 and provided additional sociodemographic survey data. Hourly average physical activity (Metabolic Equivalent of Task (MET)) and surrounding greenness (NDVI) were derived from the Calfit mobile application collecting accelerometer and location data. Hourly apparent temperature was calculated from temperature and relative humidity, which were obtained from local meteorological stations along with other meteorological covariates (rainfall, windspeed, and sky darkness). We assessed the interaction effects of apparent temperature and surrounding greenness on hourly physical activity for each city using linear mixed models, while adjusting for meteorological, demographic, and time-related variables.

RESULTS

We found significant interactions between apparent temperature and surrounding greenness on hourly physical activity in three of four cities, aside from the coastal city of Barcelona. Significant quadratic effects of apparent temperature were found in the highest level of surrounding greenness for Stoke-on-Trent and Doetinchem, with 4% decrease in median MET observed for a 10°C departure from optimal temperature (15.2°C and 14.6°C, respectively). Significant linear effects were found for higher levels of surrounding greenness in Kaunas, whereby an increase of 10°C was associated with ∼4% increase in median MET.

CONCLUSION

Apparent temperature and surrounding greenness interacted in the effect on hourly physical activity across three of four European cities, with varying effect between cities. While quadratic effects of temperature suggest diminishing levels of physical activity in the highest greenness levels in cities of temperate climates, the variation in surrounding greenness between cities could be further explored, particularly by looking at indoor-outdoor locations. The study findings support the need for evidence-based physical activity promotion and urban design.

Daily Motivational Text Messages to Promote Physical Activity in University Students: Results From a Microrandomized Trial

BACKGROUND

Low physical activity is an important risk factor for common physical and mental disorders. Physical activity interventions delivered via smartphones can help users maintain and increase physical activity, but outcomes have been mixed.

PURPOSE

Here we assessed the effects of sending daily motivational and feedback text messages in a microrandomized clinical trial on changes in physical activity from one day to the next in a student population.

METHODS

We included 93 participants who used a physical activity app, "DIAMANTE" for a period of 6 weeks. Every day, their phone pedometer passively tracked participants' steps. They were microrandomized to receive different types of motivational messages, based on a cognitive-behavioral framework, and feedback on their steps. We used generalized estimation equation models to test the effectiveness of feedback and motivational messages on changes in steps from one day to the next.

RESULTS

Sending any versus no text message initially resulted in an increase in daily steps (729 steps, p = .012), but this effect decreased over time. A multivariate analysis evaluating each text message category separately showed that the initial positive effect was driven by the motivational messages though the effect was small and trend-wise significant (717 steps; p = .083), but not the feedback messages (-276 steps, p = .4).

CONCLUSION

Sending motivational physical activity text messages based on a cognitive-behavioral framework may have a positive effect on increasing steps, but this decreases with time. Further work is needed to examine using personalization and contextualization to improve the efficacy of text-messaging interventions on physical activity outcomes.

CLINICALTRIALS.GOV IDENTIFIER

NCT04440553.

Reliability of a smartphone application to measure physical activity

The aim of this study was to evaluate how accurate is a smartphone app to measure a physical activity parameter (steps). Physical Education undergraduate students (n = 46), both male and female, were recruited. A tally counter, a validated device (Xiaomi Mi Band 2®) and My Active Life app were used to perform the steps count. Each participant took three low-intensity treadmill walks (5 km h^-1), with a number of target steps (500-, 1000- and 1500-steps walk). Visual agreement analyses was performed through Bland-Altman plots. There was no significant interaction between steps walks and device during treadmill walking test (F_(2,84) = 3.854; p = 0.07). Differences in steps measured by Mi Band were not different from 0 in 500-steps walk (p = 0.243) and 1000-steps walk (p = 0.350), and in My Active Life in 500-steps walk (p = 0.177) and 1500-steps walk (p = 0.221). Bland-Altman analyses indicated an acceptable agreement between My active Life app and Mi Band devices for 1000-steps walk (-359.01; 310.43) and 1500-steps walk (-572.97; 377.11). In conclusion, My Active Life app showed accuracy in measuring total steps, in longer walking activities (e.g. higher than 1000 steps), and can be used on a daily basis and in research setting.

Step and Distance Measurement From a Low-Cost Consumer-Based Hip and Wrist Activity Monitor: Protocol for a Validity and Reliability Assessment

Background

Self-tracking via wearable and mobile technologies is becoming an essential part of personal health management. At this point, however, little information is available to substantiate the validity and reliability of low-cost consumer-based hip and wrist activity monitors, with regard more specifically to the measurements of step counts and distance traveled while walking.

Objective

The aim of our study is to assess the validity and reliability of step and distance measurement from a low-cost consumer-based hip and wrist activity monitor specific in various walking conditions that are commonly encountered in daily life. Specifically, this study is designed to evaluate whether and to what extent validity and reliability could depend on the sensor placement on the human body and the walking task being performed.

Methods

Thirty healthy participants will be instructed to wear four PBN 2433 (Nakosite) activity monitors simultaneously, with one placed on each hip and each wrist. Participants will attend two experimental sessions separated by 1 week. During each experimental session, two separate studies will be performed. In study 1, participants will be instructed to complete a 2-minute walk test along a 30-meter indoor corridor under 3 walking speeds: very slow, slow, and usual speed. In study 2, participants will be required to complete the following 3 conditions performed at usual walking speed: walking on flat ground, upstairs, and downstairs. Activity monitor measured step count and distance values will be computed along with the actual step count (determined from video recordings) and distance (measured using a measuring tape) to determine validity and reliability for each activity monitor placement and each walking condition.

Results

Participant recruitment and data collection began in January 2020. As of June 2020, we enrolled 8 participants. Dissemination of study results in peer-reviewed journals is expected in spring 2021.

Conclusions

To the best of our knowledge, this is the first study that examines the validity and reliability of step and distance measurement during walking using the PBN 2433 (Nakosite) activity monitor. Results of this study will provide beneficial information on the effects of activity monitor placement, walking speed, and walking tasks on the validity and reliability of step and distance measurement. We believe such information is of utmost importance to general consumers, clinicians, and researchers.

International Registered Report Identifier (IRRID)

DERR1-10.2196/21262

Validity of Consumer Activity Monitors and an Algorithm Using Smartphone Data for Measuring Steps during Different Activity Types

Background: Consumer activity monitors and smartphones have gained relevance for the assessment and promotion of physical activity. The aim of this study was to determine the concurrent validity of various consumer activity monitor models and smartphone models for measuring steps. Methods: Participants completed three activity protocols: (1) overground walking with three different speeds (comfortable, slow, fast), (2) activities of daily living (ADLs) focusing on arm movements, and (3) intermittent walking. Participants wore 11 activity monitors (wrist: 8; hip: 2; ankle: 1) and four smartphones (hip: 3; calf: 1). Observed steps served as the criterion measure. The mean average percentage error (MAPE) was calculated for each device and protocol. Results: Eighteen healthy adults participated in the study (age: 28.8 ± 4.9 years). MAPEs ranged from 0.3–38.2% during overground walking, 48.2–861.2% during ADLs, and 11.2–47.3% during intermittent walking. Wrist-worn activity monitors tended to misclassify arm movements as steps. Smartphone data collected at the hip, analyzed with a separate algorithm, performed either equally or even superiorly to the research-grade ActiGraph. Conclusion: This study highlights the potential of smartphones for physical activity measurement. Measurement inaccuracies during intermittent walking and arm movements should be considered when interpreting study results and choosing activity monitors for evaluation purposes.

Mobile Apps to Quantify Aspects of Physical Activity: a Systematic Review on its Reliability and Validity

The purpose of this study was to systematically review and evaluate the evidence on the accuracy (validity) and consistency (reliability) of mobile apps used to quantify physical activity. Systematic literature searches were conducted in Pubmed, Science Direct, Web of Science, Physiotherapy Evidence Database (PEDro), Academic Search Complete and IEEE Xplore. Studies were included if they reported on the validity and/or reliability of a mobile application aiming primarily at measuring physical activity in humans with or without pathology. The reference lists of included articles were also screened for reports not identified through electronic searches. The methodological quality of included studies was assessed by 2 independent reviewers and data extracted by one reviewer and checked for accuracy by a second reviewer. A total of 25 articles were included in this review, of which 18 refer to validity and 7 to both validity and reliability. Mean percentage difference was used as an indicator of validity and varied between 0.1% and 79.3%. Intraclass Correlation Coefficients varied between 0.02 and 0.99 indicating poor to excellent reliability. There is conflicting and insufficient evidence on the validity and reliability, respectively, of apps for measuring physical activity. Nevertheless, velocity and the place where the smartphone is carried seem to have an impact on validity.