Step Activity Monitor Research Articles

Comparison of community ambulation intensity determined from overground and treadmill walking cadence cut points: Is there a relationship between step activity measures and predicted VO2 max in healthy children and adults?

BackgroundThis study was designed to evaluate the effect of using maximal cadence criteria cut points established during overground and treadmill walking, on intensity outputs measured during community ambulation. The second aim was to establish the relationship between cardiovascular fitness (predicted VO2 max capacity) and community ambulation intensity performance, in typically developing individuals. Research QuestionWhat is the effect on intensity measures when using cadence cut point criteria derived from overground and treadmill walking and does predicted VO2 max correlate with exercise related community activity in a typically developing population? MethodsA group of 37 typically developing participants between 8 and 27 years of age, underwent a graded submaximal VO2 testing protocol followed by a typical week of community ambulation, recorded with a step activity monitor. Maximum cadence criteria established during overground and treadmill walking were applied and the data were compared. The weekly step activity variables included: total steps, total ambulatory time, intensity, duration, and volume. Predicted VO2 Max was calculated, and correlations calculated to step activity outputs. ResultsResults showed significant differences (p<0.001) between cadence cut point criteria across all intensity measures except in the amount of time spent in the 30–60 % intensity category (p=0.182). Predicted VO2 max did not significantly correlate with step activity outputs related to exercise (moderate+ intensity and long duration ambulatory bouts; p>0.277). SignificanceThis study illustrates the importance of close consideration in applying recommended cut off criteria when assessing intensity outputs from step activity data. Cadence from both overground and treadmill walking were collected in a controlled lab setting, but the influence of the treadmill mechanical and forced cadence criteria must be considered when selecting intensity cut points.

How should we measure physical activity after stroke? An international consensus.

Physical activity is important for secondary stroke prevention. Currently, there is inconsistency of outcomes and tools used to measure physical activity following stroke. To establish internationally agreed recommendations to enable consistent measurement of post-stroke physical activity. Stroke survivors and carers were surveyed online once regarding what is important in physical activity measurement. Three survey rounds with expert stroke researchers and clinicians were conducted using Keeney's Value-Focused Thinking Methodology. Survey 1 identified physical activity tools, outcomes, and measurement considerations which were ranked in Survey 2. Consensus recommendations on tools were then formulated by the consensus group based on survey responses. In Survey 3, participants reviewed ranked results and evidence gathered to determine their support for consensus recommendations. Twenty-five stroke survivors, 5 carers, 18 researchers, and 17 clinicians from 16 countries participated. Time in moderate-vigorous physical activity and step count were identified as the most important outcomes to measure. Key measurement considerations included the ability to measure across frequency, intensity, duration domains in real-world settings; user-friendliness, comfort, and ability to detect changes. Consensus recommendations included using the Actigraph, Actical, and Activ8 devices for physical activity intensity; ActivPAL for duration and Step Activity Monitor for frequency; and the IPAQ and PASE questionnaires. Survey 3 indicated 100% support for device and 96% for questionnaire recommendations. These consensus recommendations can guide selection of physical activity measurement tools and outcomes. Tool selection will depend on measurement purpose, user-knowledge, and resources. Comprehensive measurement requires the use of devices and questionnaires.

Diabetes Is Negatively Associated With Meeting Physical Activity Time-Intensity Guidelines in Patients With Claudication.

We determined the percentage of patients with peripheral artery disease (PAD) and claudication who meet the 2018 physical activity (PA) time-intensity guidelines, and we identified the clinical characteristics associated with the status of meeting the guidelines. Five hundred seventy-two patients were assessed on their daily ambulatory activity for 1 wk with a step activity monitor, and were evaluated on whether or not they achieved 150 min/wk of moderate-intensity PA. Thirty-one percent (n = 175) of the patients with PAD met the PA time-intensity guidelines and 69% (n = 397) did not. In a final multivariable logistic regression model identifying the independent predictors of meeting the PA time-intensity guidelines from clinical characteristics, diabetes was the only significant variable entered (OR = 0.310: 95% CI, 0.175-0.538; P < .001) and was associated with a 69% lower chance of meeting the guidelines. Patients with diabetes spent less daily time in moderate-intensity ambulatory PA than patients without diabetes (15 ± 13 vs 23 ± 20 min/d; P < .001). Thirty-one percent of patients with PAD and claudication met the PA time-intensity guidelines. Furthermore, patients with diabetes were least likely to meet the PA time-intensity guidelines, as they had a 69% lower chance than patients without diabetes. The clinical significance is that PAD patients who have diabetes are particularly susceptible to being physically sedentary, and are therefore prime patients who should be encouraged to increase their daily PA.

Diabetes Is Negatively Associated With Meeting Physical Activity Time-intensity Guidelines In Patients With Claudication

PURPOSE: We determined the percentage of patients with peripheral artery disease (PAD) and claudication who meet the 2018 physical activity time-intensity guidelines, and we identified the clinical characteristics associated with the status of meeting the guidelines. METHODS: Five hundred seventy-two patients were assessed on their daily ambulatory activity for one week with a step activity monitor, and were evaluated on whether they achieved less than 150 minutes of moderate intensity physical activity per week, or whether they were above this threshold. Patients were also evaluated on demographic and clinical characteristics, as well as ankle/brachial index and ambulatory function. RESULTS: Thirty-one percent (n = 175) of the PAD patients met the physical activity time-intensity guidelines and 69% (n = 397) did not. The respective groups were significantly different on ankle/brachial index (0.75 ± 0.22 vs. 0.65 ± 0.22; p < 0.001; means±SD); 6-minute walk distance (m) (415 ± 79 vs. 335 ± 88; p < 0.001); and prevalence of diabetes (24.0% vs. 50.4%; p < 0.001), metabolic syndrome (74.3% vs. 84.1%; p = 0.008), and dyslipidemia (83.4% vs. 93.0%; p = 0.001). In multivariable logistic regression models evaluating the association between meeting the physical activity time-intensity guidelines and each clinical characteristic, diabetes (odds ratio [OR] = 0.298; 95% CI: 0.175, 0.499; p < 0.001), metabolic syndrome (OR = 0.455; 95% CI: 0.255, 0.811; p = 0.007) and dyslipidemia (OR = 0.467; 95% CI: 0.225, 0.964; p = 0.039) were significantly associated with a lower chance of meeting the guidelines. CONCLUSIONS: Thirty-one percent of patients with PAD and claudication met the physical activity time-intensity guidelines. Furthermore, patients with diabetes, metabolic syndrome, and dyslipidemia were least likely to meet the physical activity time-intensity guidelines. Diabetes was particularly detrimental, as patients with diabetes were 71% less likely to meet the physical activity time-intensity guidelines than patients without diabetes. The clinical significance is that PAD patients who have diabetes are particularly susceptible to being physically sedentary, and are therefore prime patients who should be encouraged to increase their daily physical activity. Supported by NIH (R01-AG-24296 and R01-AG-16685).

Effectiveness Of A Peer Guided Physical Activity Via Telehealth Program (PACT) In Adults With Autism: A Pilot Randomized Controlled Trial

PURPOSE: Adults with autism spectrum disorder (ASD) are at increased risk for obesity and cardiovascular disease as they face limited opportunities and access to physical activity (PA). Barriers to PA may include impairments with cognitive/social/communication, limited access due to transportation needs/costs, and more recently, the Covid-19 pandemic. The objective of this study is to determine whether a 10-week Physical Activity via Telehealth (PACT) program, a peer-guided telehealth + use of a wearable step activity device (Fitbit) would improve PA outcomes in adults with ASD. METHODS: Eighteen subjects (11-males), aged 18-32 diagnosed with ASD were randomized into either a PACT or Wait-list Control (WLC) group. Anthropometrics to determine Body Mass Index (BMI) and Waist to Height Ratio (WHtR) was collected via guided instruction. Self-report and steps/day PA data were collected utilizing the Godin Leisure Survey (GL), research-grade step activity monitor (StepWatch), and FitBit Inspire (FB). PACT included 10-weeks of peer-supported telehealth sessions + daily step activity self-monitoring with FB device. Data was analyzed and interpreted using descriptive statistics, repeated-measures ANOVA, and paired T-tests. RESULTS: All subjects completed PACT and were compliant with FB during PACT and WLC phases, and 9 completed the WLC prior to crossing over. Mean BMI, and WHtR was 28.6 kg/m2and .56. No differences in anthropometrics or steps/day PA between PACT and WLC group at baseline. Self-report of PA increased at 10-weeks for PACT group as per GL from 26.2 to 67.8, p = .002. Although not significant, StepWatch steps/day trended upwards from 6,700 to 7,756 for PACT only while trending downward by 1453 steps/day for WLC group. The effects of PACT over time for all participants following PACT revealed an increase in steps/day from 6,727 to 7,316, p = .048. CONCLUSIONS: Adults with ASD who completed PACT demonstrated improvements in self-report PA and a positive trend in steps/day. Although, a small cohort, study results support use of a Fitbit device and peer-supported telehealth for this population who face multiple barriers to participate in community-based PA programs and have greater propensity towards obesity and high-risk abdominal adiposity.

Agreement, Reliability, and Concurrent Validity of an Outdoor, Wearable-Based Walk Ratio Assessment in Healthy Adults and Chronic Stroke Survivors.

Purpose: The walk ratio (WR)—the step-length/cadence relation—is a promising measure for gait control. GPS-running watches deliver clinically relevant outcomes including the WR. The aim of this study was to determine test-retest agreement, reliability and concurrent validity of an outdoor WR assessment using a GPS-running watch. Methods: Healthy adults and moderate—high functioning stroke survivors (≥6 months), performed the 1 km-outdoor walk twice using a GPS-running watch (Garmin Forerunner 35, GFR35) and a Step Activity Monitor (SAM 3). Global cognition was assessed using the Montreal Cognitive Assessment. Test-retest agreement and reliability were assessed using Bland-Altman plots, standard error of measurement (SEM), intraclass correlation coefficients (ICCs) and smallest detectable changes (SDCs). Concurrent validity was determined by the mean difference (MD), standard error (SE), mean absolute percentage errors (MAPEs) and Spearman’s Rho between GFR35 and SAM3. WR values of the two groups were compared by a Welch’s test. A hierarchical multiple regression was performed with the WR as dependent variable and possible predictors as independent variables. Results: Fifty-one healthy adults [median: 60.0 (47.0, 67.0) years) and 20 stroke survivors [mean: 63.1 (12.4) years, median: 76 (30, 146) months post-stroke] were included. Test-retest agreement and reliability were excellent (SEM% ≤ 2.2, ICCs > 0.9, SDC% ≤ 6.1) and concurrent validity was high (MAPE < 5, ρ > 0.7) for those walking ≥ 1 m/s. Walking < 1 m/s impaired accurate step counting and reduced agreement, reliability, and validity. The WR differed between healthy adults and stroke survivors (t = −2.126, p = 0.045). The hierarchical regression model including stroke and global cognition (Montreal Cognitive Assessment, 0—30) explained 25% of the WR variance (ΔR2 = 0.246, p < 0.001). Stroke had no effect (β = −0.05, p = 0.682), but global cognition was a predictor for an altered WR (β = 0.44, p = 0.001). Discussion: The outdoor WR assessment using the GFR35 showed excellent test-retest agreement, reliability and concurrent validity in healthy adults and chronic stroke survivors walking at least 1 m/s. As the WR seems relevant in chronic stroke, future studies should further investigate this parameter.

Step Activity Monitoring in Boys with Duchenne Muscular Dystrophy and its Correlation with Magnetic Resonance Measures and Functional Performance.

Muscles of boys with Duchenne muscular dystrophy (DMD) are progressively replaced by fatty fibrous tissues, and weakness leads to loss of ambulation (LoA). Step activity (SA) monitoring is a quantitative measure of real-world ambulatory function. The relationship between quality of muscle health and SA is unknown in DMD. To determine SA in steroid treated boys with DMD across various age groups, and to evaluate the association of SA with quality of muscle health and ambulatory function. Quality of muscle health was measured by magnetic resonance (MR) imaging transverse magnetization relaxation time constant (MRI-T2) and MR spectroscopy fat fraction (MRS-FF). SA was assessed via accelerometry, and functional abilities were assessed through clinical walking tests. Correlations between SA, MR, and functional measures were determined. A threshold value of SA was determined to predict the future LoA. The greatest reduction in SA was observed in the 9- < 11years age group. SA correlated with all functional and MR measures.10m walk/run test had the highest correlation with SA. An increase in muscle MRI-T2 and MRS-FF was associated with a decline in SA. Two years prior to LoA, SA in boys with DMD was 32% lower than age matched boys with DMD who maintained ambulation for more than two-year period. SA monitoring can predict subsequent LoA in Duchenne, as a daily step count of 3200 at baseline was associated with LoA over the next two-years. SA monitoring is a feasible and accessible tool to measure functional capacity in the real-world environment.

Association Between Meeting Physical Activity Time-Intensity Guidelines With Ambulation, Quality of Life, and Inflammation in Claudication.

The aim of this investigation was to determine if meeting the 2018 physical activity (PA) time-intensity guidelines was associated with better ambulatory function, health-related quality of life (HRQoL), vascular function, and inflammation than failing to meet the guidelines in patients with peripheral artery disease and claudication. Second, we determined the optimal number of total steps/d and steps taken at moderate cadence needed to meet the PA time-intensity guidelines. Five hundred seventy-two patients were assessed on daily ambulatory activity for 1 wk with a step activity monitor, and were grouped according to whether they achieved &lt;150 min/wk of moderate-intensity PA (group 1 = do not meet guidelines; n = 397) or whether they were above this threshold (group 2 = meet guidelines; n = 175). Treadmill peak walking time (mean ± SD) was higher ( P &lt; .001) in group 2 (709 ± 359 sec) than in group 1 (427 ± 281 sec). The physical function HRQoL score was higher ( P &lt; .001) in group 2 (61 ± 22%) than in group 1 (44 ± 21%). High-sensitivity C-reactive protein was lower ( P &lt; .001) in group 2 (3.6 ± 4.5 mg/L) than in group 1 (5.9 ± 6.1 mg/L). Finally, ≥7675 total steps/d and ≥1660 steps/d at moderate cadence were optimal thresholds associated with meeting PA guidelines. Patients with claudication who meet the 2018 PA time-intensity guidelines for US adults had better ambulation, HRQoL, and vascular outcomes than those who failed to meet the PA guidelines. Patients with claudication best achieved the PA time-intensity guidelines by taking ≥7675 total steps/d, and ≥1660 steps/d at a moderate cadence.

Light and moderate intensity physical activity are associated with better ambulation, quality of life, and vascular measurements in patients with claudication

ObjectiveWe sought to determine whether patients with claudication who reported performing either light intensity physical activity (LPA) or moderate-to-vigorous intensity physical activity (MVPA) would have higher levels of objectively determined physical activity and better physical function, health-related quality of life (HRQoL), and vascular measures, consisting of exercise time to minimum calf muscle oxygen saturation (StO2) and high-sensitivity C-reactive protein, than patients who reported being physically sedentary. MethodsA total of 269 patients were assessed using the Johnson Space Center physical activity scale. The patients were grouped according to whether they performed no physical activities (n = 75), LPAs (n = 140), or MVPAs (n = 54). The primary measurements were the total daily steps obtained from a step activity monitor worn for 1 week, peak walking time obtained from a treadmill test, physical function score on the Medical Outcomes Study short-form 36-item survey to assess HRQoL, and high-sensitivity C-reactive protein. ResultsThe total daily steps was significantly different among the groups. Both the LPA group (mean ± standard deviation, 7878 ± 2808 steps/d) and the MVPA group (mean, 8551 ± 3365 steps/d) had taken more daily steps (P < .01) than had the sedentary group (mean, 3323 ± 986 steps/d). The treadmill peak walking time was significantly different among the three groups. Both the LPA group (433 ± 296 seconds) and the MVPA group (548 ± 300 seconds) had had a greater peak walking time (P < .01) than that of the sedentary group (302 ± 210 seconds). The physical function score was also significantly different among the groups. The LPA group (44% ± 20%) and MVPA group (58% ± 19%) both had had higher scores (P < .01) than the sedentary group (36% ± 20%). In addition, the exercise time to the minimum calf muscle StO2 was significantly different among the groups. Both the LPA group (215 ± 238 seconds) and the MVPA group (377 ± 351 seconds) had had greater values (P < .05 and P < .01, respectively) than the sedentary group (147 ± 172 seconds). Finally, the high-sensitivity C-reactive protein level was significantly different among the groups. Both the LPA group (4.8 ± 5.5 mg/L) and the MVPA group (3.5 ± 3.6 mg/L) had had lower values (P < .01) than the sedentary group (8.6 ± 8.4 mg/L). ConclusionsPatients with claudication who reported performing LPA had greater amounts of objectively determined physical activity levels and better physical function, HRQoL, and vascular measures than those who reported being physically sedentary. Furthermore, these favorable results associated with LPA were even more pronounced for the patients who performed MVPA compared with those who were sedentary. The clinical significance is that our results have shown that engaging in any physical activity, even at relatively light intensity, is associated with favorable health and vascular measures for patients with claudication.

Sex Differences in Physical Activity in People After Stroke: A Cross-sectional Study.

Adequate physical activity after stroke is critical for cardiovascular health. Although sex is a potential factor associated with post-stroke physical activity, its mechanism remains unclear. This study aimed to examine sex differences in human physical activity following stroke. A cross-sectional study with 62 participants (men: 42, women: 20) was conducted. Physical activity was measured for three consecutive days using a step activity monitor. The walking durations per day in light physical activity, moderate-to-vigorous physical activity, and total physical activity were calculated. Sex differences in walking duration were compared using Welch's t-tests or Mann-Whitney U tests. Women had a significantly greater walking duration in light physical activity and in total than did the men. In contrast, no significant differences were found in moderate-to-vigorous physical activity. This study reported sex differences in the walking duration after stroke. Moreover, it found that women spent more time in low intensity physical activity than men. Our results will be useful for planning interventions to increase physical activity and decrease sedentary behavior after stroke.

The Effect of Low-Intensity Daily Walking Activity on Cognitive and Brain Function in Older Adults

Physical activity is an effective intervention to prevent or delay cognitive decline and dementia in older adults; however, many have difficulty achieving recommended moderate- to vigorous-intensity guidelines. This study examined the impact of low-intensity daily walking activity on executive cognitive and brain function in 66 older adults (mean age=67.26 ; SD=6.04). Daily walking activity was measured using a step activity monitor and brain function was assessed using functional magnetic resonance imaging during the Flanker task. Analyses included whole and region of interest (ROI) in the right middle frontal gyrus (RMFG), occipital cortex (OCC) and anterior cingulate (ACC). Partial correlations were performed between step activity, behavioral performance, and ROI activation, adjusting for age and education. Most of the step activity was in the low-intensity range. No associations were observed between step activity and task performance (p>.05). Task-related activation occurred in the RMFG, lateral OCC and paracingulate (p<.01). Increased activation in the RMFG was associated with greater amount r(62)=.390, p=.001, duration r(62)=.309, p=.013 and frequency r(62)=.327, p=.007 of step activity. Stratification by sex revealed a positive association between amount of step activity and RMFG activation in women r(44)= .360, p=.014, but not men. Whole brain correlation revealed that amount of step activity was positively associated with precuneus activation (p<.01), an area impacted early in Alzheimer’s disease. These results support the benefits of low intensity daily walking activity on prefrontal function in older adults and suggest the importance of designing attainable and sustainable physical activity interventions to promote brain health in older adults.

Association Between Meeting Physical Activity Guidelines with Ambulation and Quality of Life in Claudication

We determined if meeting the 2018 physical activity guidelines was associated with better ambulatory function, health-related quality of life, and inflammation than failing to meet the guidelines in patients with peripheral artery disease and claudication. Secondly, we determined the optimal number of total daily steps that are needed to meet the physical activity guidelines. Five hundred seventy-two patients were assessed on their daily ambulatory activity for one week with a step activity monitor, and were grouped according to whether they achieved less than 150 minutes of moderate intensity physical activity per week (Group 1=Do Not Meet Guidelines; n=397), or whether they were above this threshold (Group 2=Meet Guidelines; n=175). Treadmill peak walking time (mean±SD) was significantly higher (p<0.001) in Group 2 (709±359 sec) than in Group 1 (427±281 sec). The health-related quality of life score for physical function was significantly higher (p<0.001) in Group 2 (61±22%) than in Group 1 (44±21%). High sensitivity C-reactive protein was significantly lower (p<0.001) in Group 2 (3.6±4.5 mg/L) than in Group 1 (5.9±6.1 mg/L). Finally, 7,675 daily steps was the optimal threshold associated with meeting the physical activity guidelines, with a sensitivity of 82.9% and a specificity of 88.4%. In conclusion, patients with claudication who meet the 2018 physical activity guidelines for US adults had better ambulation, HRQoL, and inflammation outcomes than those who failed to meet the guidelines. From a practical standpoint, patients with claudication best achieved the physical activity guidelines by taking a total of 7,675 daily steps.

The Effect of Low-Intensity Daily Walking Activity on Cognitive and Brain Function in Older Adults

Physical activity is an effective intervention to prevent or delay cognitive decline and dementia in older adults; however, many have difficulty achieving recommended moderate- to vigorous-intensity guidelines. This study examined the impact of low-intensity daily walking activity on executive cognitive and brain function in 66 older adults (mean age=67.26 ; SD=6.04). Daily walking activity was measured using a step activity monitor and brain function was assessed using functional magnetic resonance imaging during the Flanker task. Analyses included whole and region of interest (ROI) in the right middle frontal gyrus (RMFG), occipital cortex (OCC) and anterior cingulate (ACC). Partial correlations were performed between step activity, behavioral performance, and ROI activation, adjusting for age and education. Most of the step activity was in the low-intensity range. No associations were observed between step activity and task performance (p>.05). Task-related activation occurred in the RMFG, lateral OCC and paracingulate (p<.01). Increased activation in the RMFG was associated with greater amount r(62)=.390, p=.001, duration r(62)=.309, p=.013 and frequency r(62)=.327, p=.007 of step activity. Stratification by sex revealed a positive association between amount of step activity and RMFG activation in women r(44)= .360, p=.014, but not men. Whole brain correlation revealed that amount of step activity was positively associated with precuneus activation (p<.01), an area impacted early in Alzheimer’s disease. These results support the benefits of low intensity daily walking activity on prefrontal function in older adults and suggest the importance of designing attainable and sustainable physical activity interventions to promote brain health in older adults.

Relationship between level of daily activity and upper-body aerobic capacity in adults with a lower limb amputation.

Previous studies show that people with lower limb amputation (LLA) have a sedentary lifestyle, reduced walking capacity, and low cardiorespiratory fitness (VO2peak). There is, however, no knowledge on the relationship between cardiorespiratory fitness and objectively measured level of physical activity in daily life. To investigate the relationship between upper-body VO2peak, physical activity levels, and walking capacity in persons with LLA. Correlational and descriptive study. Fourteen participants with LLA performed an assessment of VO2peak on an arm-crank ergometer and walking capacity (preferred walking speed and 2-minute walking test). Level of physical activity was measured over 7 days with a step activity monitor (number of steps; sedentary time; and proportion of low-intensity, moderate-intensity, high-intensity, and peak-intensity activity level). VO2peak correlated significantly with number of steps per day (r = 0.696, p = 0.006), sedentary time (r = -0.618, p = 0.019), high-intensity activity level (r = 0.769, p = 0.001), and peak-intensity activity level (r = 0.674, p = 0.008). After correcting for age, correlations were still large and significant. Large correlations were also found between VO2peak, preferred walking speed (r = 0.586, p = 0.027), and 2-minute walking test (r = 0.649, p = 0.012). We provide the first evidence of the strong relationships between upper-body VO2peak, sedentary behavior, high-intensity activity level, and walking capacity in persons with LLA. Further research is needed to investigate the potential effect of upper-body cardiorespiratory fitness on the level of activity in daily life, or vice versa.

Physical Activity Monitoring Using a Fitbit Device in Ischemic Stroke Patients: Prospective Cohort Feasibility Study.

BackgroundContinuous tracking of ambulatory activity in real-world settings using step activity monitors has many potential uses. However, feasibility, accuracy, and correlation with performance measures in stroke patients have not been well-established.ObjectiveThe primary study objective was to determine adherence with wearing a consumer-grade step activity monitor, the Fitbit Charge HR, in home-going ischemic stroke patients during the first 90 days after hospital discharge. Secondary objectives were to (1) determine accuracy of step counts of the Fitbit Charge HR compared with a manual tally; (2) calculate correlations between the Fitbit step counts and the mobility performance scores at discharge and 30 days after stroke; (3) determine variability and change in weekly step counts over 90 days; and (4) evaluate patient experience with using the Fitbit Charge HR poststroke.MethodsA total of 15 participants with recent mild ischemic stroke wore a Fitbit Charge HR for 90 days after discharge and completed 3 mobility performance tests from the National Institutes of Health Toolbox at discharge and Day 30: (1) Standing Balance Test, (2) 2-Minute Walk Endurance Test, and (3) 4-Meter Walk Gait Speed Test. Accuracy of step activity monitors was assessed by calculating differences in steps recorded on the step activity monitor and a manual tally during 2-minute walk tests.ResultsParticipants had a mean age of 54 years and a median modified Rankin scale score of 1. Mean daily adherence with step activity monitor use was 83.6%. Mean daily step count in the first week after discharge was 4376. Daily step counts increased slightly during the first 30 days after discharge (average increase of 52.5 steps/day; 95% CI 32.2-71.8) and remained stable during the 30-90 day period after discharge. Mean step count difference between step activity monitor and manual tally was –4.8 steps (–1.8%). Intraclass correlation coefficients for step counts and 2-minute walk, standing balance, and 4-meter gait speed at discharge were 0.41 (95% CI –0.14 to 0.75), –0.12 (95% CI –0.67 to 0.64), and 0.17 (95% CI –0.46 to 0.66), respectively. Values were similarly poor at 30 days.ConclusionsThe use of consumer-grade Fitbit Charge HR in patients with recent mild stroke is feasible with reasonable adherence and accuracy. There was poor correlation between step counts and gait speed, balance, and endurance. Further research is needed to evaluate the association between step counts and other outcomes relevant to patients, including patient-reported outcomes and measures of physical function.

SBAUPT: Azimuth SBUPT for Frequent Full Attitude Correction of Smartphone-Based PDR

The growing market of smart devices make them appealing for various applications. Motion tracking can be achieved using such devices, and is important for various applications such as navigation, search and rescue, health monitoring, and quality of life-style assessment. Step detection is a crucial task that affects the accuracy and quality of such applications. In this paper, a new step detection technique is proposed, which can be used for step counting and activity monitoring for health applications as well as part of a Pedestrian Dead Reckoning (PDR) system. Inertial and Magnetic sensors measurements are analyzed and fused for detecting steps under varying step modes and device pose combinations using a free-moving handheld device (smartphone). Unlike most of the state of the art research in the field, the proposed technique does not require a classifier, and adaptively tunes the filters and thresholds used without the need for presets while accomplishing the task in a real-time operation manner. Testing shows that the proposed technique successfully detects steps under varying motion speeds and device use cases with an average performance of 99.6% and outperforms some of the state of the art techniques that rely on classifiers and commercial wristband products.

Readiness to Change is Related to Real-World Walking and Depressive Symptoms in Chronic Stroke.

The transtheoretical model is a health behavior model used to understand an individual's readiness to change their behavior. This study aims to apply the transtheoretical model in understanding a person with stroke's readiness to change their activity level, as it relates to physical capacity, physical health, depressive symptoms, self-efficacy, and daily stepping activity. This was a cross-sectional analysis of baseline data from a clinical trial. Participants' readiness to change their activity levels was measured via self-report and daily stepping activity was measured using a step activity monitor. Robust regression (M-estimation with robust standard errors) was used to test the relationship between readiness to change and measures of physical capacity (6-minute walk test, self-selected walking speed), physical health (body mass index, age-adjusted Charlson Comorbidity Index), depressive symptoms (Patient Health Questionnaire-9), self-efficacy (Activities-Specific Balance Confidence Scale), and daily stepping (steps per day). A total of 274 individuals were included in the analysis. Adjusted for age, readiness to change was positively related to daily stepping (β = 0.29, P < 0.001) and negatively related to depressive symptoms (β = -0.13, P = 0.01). Readiness to change was not significantly associated with measures of physical capacity, physical health, or self-efficacy. These results suggest that individuals with stroke in the later stages of change may demonstrate greater daily stepping activity and lower depressive symptoms compared with those in earlier stages. Understanding the relationship between readiness to change, daily stepping, and depressive symptoms will help clinicians implement appropriate stage-specific intervention strategies and facilitate greater improvement in activity levels.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A333).

Association between meeting daily step count goals with ambulatory function and quality of life in patients with claudication

ObjectiveTo determine (a) whether patients with peripheral artery disease (PAD) who walked at least 7000 and 10,000 steps/day had better ambulatory function and health-related quality of life (HRQoL) than patients who walked less than 7000 steps/day, and (b) whether differences in ambulatory function and HRQoL in patients grouped according to these daily step count criteria persisted after adjusting for covariates. MethodsTwo hundred forty-eight patients were assessed on their daily ambulatory activity for 1 week with a step activity monitor, and were grouped according to daily step count targets. Patients who took fewer than 7000 steps/day were included in group 1 (n = 153), those who took 7000 to 9999 steps/day were included in group 2 (n = 57), and patients who took at least 10,000 steps/day were included in group 3 (n = 38). Primary outcomes were the 6-minute walk distance (6MWD) and Walking Impairment Questionnaire (WIQ) distance score, which is a disease-specific measurement of HRQoL. Patients were further characterized on demographic variables, comorbid conditions, and cardiovascular risk factors. ResultsThe groups were significantly different on ankle-brachial index (P = .02), and on the prevalence of hypertension (P = .04), diabetes (P < .01), abdominal obesity (P < .01), arthritis (P = .04), and chronic obstructive pulmonary disease (P < .01). Thus, these variables served as covariates in adjusted analyses, along with age, weight, and sex. The 6MWD (mean ± standard deviation) was significantly different among the groups in unadjusted (P < .01) and adjusted (P < .01) analyses (group 1, 313 ± 90 m; group 2, 378 ± 84 m; and group 3, 414 ± 77 m), with groups 2 and 3 having a higher 6MWD than group 1 (P < .01). The WIQ distance score was significantly different among the groups in unadjusted (P < .01) and adjusted (P < .01) analyses (group 1, 30 ± 30%; group 2, 45 ± 35%; and group 3, 47 ± 34%), with groups 2 and 3 having higher WIQ distance scores than group 1 (P < .01). ConclusionsPatients with PAD who walked more than 7000 and 10,000 steps/day had greater ambulatory function and HRQoL than patients who walked fewer than 7000 steps/day. Second, the greater ambulatory function and HRQoL associated with walking 7000 and 10,000 steps/day persisted after adjusting for covariates. This study provides preliminary evidence that patients with PAD who walk more than 7000 steps/day have better ambulatory function and HRQoL than patients below this threshold.

Abstract 14421: Association Between Meeting Daily Step Count Goals With Ambulatory Function and Quality of Life in Patients With Claudication

Introduction: The aims were to determine (a) whether patients with peripheral artery disease (PAD) who walked at least 7,000 and 10,000 steps/day had better ambulatory function and health-related quality of life (HRQoL) than patients who walked less than 7,000 steps/day, and (b) whether these group differences persisted after adjusting for covariates. Hypothesis: Patients who walk at least 7,000 steps/day have significantly better ambulatory function, as measured by greater 6-minute walk distance (6MWD), and better HRQoL, as measured by a higher distance score on the Walking Impairment Questionnaire (WIQ), than patients who walked less than 7,000 steps/day, and that patients who walked more than 10,000 steps/day would have the best values. Furthermore, group differences in the primary outcomes would persist after adjustment for covariates. Methods: Two hundred forty-eight patients were assessed on their daily activity for one week with a step activity monitor, and were grouped according to daily step counts as follows: Group 1 (&lt;7,000 steps/day; n=153), Group 2 (7,000-9,999 steps/day; n=57), Group 3 (&gt;10,000 steps/day; n=38). Primary outcomes were 6MWD and WIQ distance score, which is a disease-specific measurement of HRQoL. Results: Groups were different (p&lt;0.05) on ankle/brachial index, and on prevalence of hypertension, diabetes, abdominal obesity, arthritis, and chronic obstructive pulmonary disease. Thus, these variables served as covariates in adjusted analyses, along with age, weight, and sex. 6MWD (mean±SD) was significantly different among the groups in unadjusted (p&lt;0.01) and adjusted (p&lt;0.01) analyses (Group 1=313±90 m, Group 2=378±84 m, Group 3=414±77 m), with Groups 2 and 3 having higher 6MWD than Group 1 (p&lt;0.01). Similar results were found for the WIQ distance score (Group 1=30±30%, Group 2=45±35%, Group 3=47±34%; p&lt;0.01). Conclusions: PAD patients who walked more than 7,000 and 10,000 steps/day had greater ambulatory function and HRQoL than patients who walked fewer than 7,000 steps/day, and this finding persisted after adjusting for covariates. The clinical significance is that PAD patients should be encouraged to walk more than 7,000 steps/day because this target is associated with greater ambulatory function and HRQoL

Daily Step Counts in Participants With and Without Peripheral Artery Disease.

We compared the prevalence of participants with and without symptomatic peripheral artery disease (PAD) who met the goals of attaining >7000 and 10 000 steps/d, and we determined whether PAD status was significantly associated with meeting the daily step count goals before and after adjusting for demographic variables, comorbid conditions, and cardiovascular risk factors. Participants with PAD (n = 396) and without PAD (n = 396) were assessed on their walking for 7 consecutive days with a step activity monitor. The PAD group took significantly fewer steps/d than the non-PAD control group (6722 ± 3393 vs. 9475 ± 4110 steps/d; P < .001). Only 37.6% and 15.7% of the PAD group attained the goals of walking >7000 and 10 000 steps/d, respectively, whereas 67.9% and 37.4% of the control group attained these goals (P < .001 for each goal). Having PAD was associated with a 62% lower chance of attaining 7000 steps/d than compared with the control group (OR = 0.383; 95% CI, 0.259-0.565; P < .001), and a 55% lower chance of attaining 10 000 steps/d (OR = 0.449; 95% CI, 0.282-0.709; P < .001). Significant covariates (P < .01) included age, current smoking, diabetes, and body mass index. Participants with symptomatic PAD had a 29% lower daily step count compared with age- and sex-matched controls, and were less likely to attain the 7000 and 10 000 steps/d goals. Additionally, participants who were least likely to meet the 7000 and 10 000 daily step count recommendations included those who were older, currently smoked, had diabetes, and had higher body mass index.