Utility of the RT3 triaxial accelerometer in free living: an investigation of adherence and data loss

Validation and Calibration for Embedding Rating of Perceived Exertion Into High-Intensity Interval Exercise in Adolescents: A Lab-Based Study

PURPOSE

Rating of perceived exertion (RPE) is a convenient and cost-effective tool that can be used to monitor high-intensity interval exercise (HIIE). However, no methodological study has demonstrated the validity of RPE in this context. Therefore, the aim of this study was to validate and calibrate RPE for monitoring HIIE in adolescents.

METHODS

RPE, heart rate (HR), and oxygen uptake (V˙O2) data were retrospectively extracted from 3 lab-based crossover studies, with a pooled sample size of 45 adolescents, performing either cycling-based or running-based HIIE sessions. Within-participant correlations were calculated for RPE-HR and RPE-V˙O2, and receiver operator characteristic curve analysis was used to establish RPE cut points.

RESULTS

The results showed that RPE-HR demonstrated acceptable criterion validity (r = .53-.74, P < .01), while RPE-V˙O2 had poor validity (r = .40-.48, P < .01), except for HIIE at 100% peak power (r = .59, P < .01). RPE cut points of 4 and 5 were established in corresponding to HR/V˙O2 based thresholds.

CONCLUSION

RPE has some utility in evaluating intensity during lab-based running or cycling HIIE in adolescents. Future studies should expand the validation and calibration of RPE for prescribing and monitoring HIIE in children and adolescents in field-based contexts.

acc: An R package to process, visualize, and analyze accelerometer data

Wearable activity monitors are now widely used in behavioral and epidemiological studies to measure physical activity in free-living conditions. Despite the widespread use in research, the development of software to explore the data collected from these devices has been limited. We present acc, a comprehensive, free, and open-source R package to provide a seamless environment for exploring accelerometer data (https://cran.r-project.org/web/packages/acc). In this article, we demonstrate the software for processing, visualizing, and analyzing accelerometer data using real and simulated datasets.

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.

Continuous pressure monitoring of inpatient spinal cord injured patients: implications for pressure ulcer development

STUDY DESIGN

Cohort observational study.

OBJECTIVES

To examine the movement profiles of individuals with spinal cord injury (SCI) during their inpatient rehabilitative phase using continuous pressure monitoring (CPM), evaluating the trends in those with skin damage.

SETTING

SCI specialist rehabilitation centre in the United Kingdom.

METHODS

Individuals with SCI (n = 12) were assessed using CPM in the bed and chair over a 24-72 h. Pressure data was used as a surrogate for movement using both nursing interpretation and an intelligent algorithm. Clinical features were obtained including participants age, injury level, ASIA score, co-morbidities and prescribed support surfaces. Trends between movement profiles (frequency and intervals), SCI demographics and observed skin damage were assessed using cross-tabulation and histograms.

RESULTS

The data revealed significant correlations (p < 0.05) between the nursing observation and algorithm for predicting movement, although the algorithm was more sensitive. Individuals with high level injuries (C1-T6) were observed to have a lower frequency of movement and larger intervals between movements when compared to low level injuries (T7-L5) during both lying and sitting periods. The individuals observed to have skin damage were predominantly those who had both a low frequency of movement and extended gaps between movements.

CONCLUSIONS

Movements for pressure relief in both the bed and chair environments were dependent on the level of injury in individuals with SCI during their inpatient rehabilitation. Distinct movement patterns corresponded with those who acquired skin damage, revealing the potential clinical applications for technologies to monitor PU risk and inform personalised care.

A qualitative investigation of activity measurement and change following a mind-body activity program for chronic pain

Increasing activity is important yet challenging among people with chronic pain. Objective assessment of activity using accelerometers (i.e., ActiGraph) has gained popularity, but reactivity to assessment and non-adherence to wearing the ActiGraph may bias data. We explored: 1) experiences of wearing the ActiGraph to identify ways to increase adherence and facilitate accurate assessment of activity; and 2) barriers and facilitators to increasing activity following two mind-body activity programs to optimize future interventions. We conducted semi-structured exit interviews with 13 participants with heterogenous chronic pain who completed a randomized controlled trial of two mind-body activity programs. We analyzed transcripts using a framework approach to generate themes. Participants indicated that receiving reminders increased ActiGraph wear adherence and reported that program skills such as gratitude, pacing, mindfulness, and deep breathing were facilitators to increasing activity, while medical problems were barriers. Interventions aiming to increase activity may benefit from emphasizing mind-body skills and sending ActiGraph wear reminders.

Effectiveness of a lumbopelvic monitor and feedback device to change postural behaviour: the ELF cluster randomised controlled trial

OBJECTIVES

The aim of this clustered, randomised controlled trial was to assess the effectiveness of a lumbopelvic postural feedback device for changing postural behaviour in a group of healthcare workers. We hypothesised that workers exposed to auditory postural feedback would reduce the number of times forward bending posture is adopted at work.

METHODS

This was a participant and assessor blinded, randomised, sham-controlled trial with blocked cluster random allocation. We recruited healthcare workers from aged care institutions. Healthcare sites were randomly allocated to the feedback or sham group (SG). A postural monitoring and feedback device was used to monitor and record lumbopelvic forward bending posture, and provided audio feedback whenever the user sustained lumbopelvic forward bending posture that exceeded predefined thresholds. The primary outcome measure was postural behaviour (exceeding thresholds). We used a robust variant of repeated measures mixed-effect model for assessing within-group and between-group differences in postural behaviour.

RESULTS

We recruited 19 sites, and 130 healthcare workers participated. There were no within-group changes on the number of times postural threshold was exceeded at 1-week follow-up (feedback group: -0.7, 95% CI -2.61 to 0.72; SG -0.3, -1.65 to 0.98), and no differences (0.05, 95% CI -1.83 to 1.94) between SG and feedback group.

CONCLUSIONS

Findings from this trial indicate that audio feedback provided by a postural monitor device did not reduce the number of times healthcare workers exceeded the postural threshold.

TRIAL REGISTRATION NUMBER

ACTRN12616000449437.

Wrist-Based Accelerometers and Visual Analog Scales as Outcome Measures for Shoulder Activity During Daily Living in Patients With Rotator Cuff Tendinopathy: Instrument Validation Study

BACKGROUND

Shoulder pain secondary to rotator cuff tendinopathy affects a large proportion of patients in orthopedic surgery practices. Corticosteroid injections are a common intervention proposed for these patients. The clinical evaluation of a response to corticosteroid injections is usually based only on the patient's self-evaluation of his function, activity, and pain by multiple questionnaires with varying metrological qualities. Objective measures of upper extremity functions are lacking, but wearable sensors are emerging as potential tools to assess upper extremity function and activity.

OBJECTIVE

This study aimed (1) to evaluate and compare test-retest reliability and sensitivity to change of known clinical assessments of shoulder function to wrist-based accelerometer measures and visual analog scales (VAS) of shoulder activity during daily living in patients with rotator cuff tendinopathy convergent validity and (2) to determine the acceptability and compliance of using wrist-based wearable sensors.

METHODS

A total of 38 patients affected by rotator cuff tendinopathy wore wrist accelerometers on the affected side for a total of 5 weeks. Western Ontario Rotator Cuff (WORC) index; Short version of the Disability of the Arm, Shoulder, and Hand questionnaire (QuickDASH); and clinical examination (range of motion and strength) were performed the week before the corticosteroid injections, the day of the corticosteroid injections, and 2 and 4 weeks after the corticosteroid injections. Daily Single Assessment Numeric Evaluation (SANE) and VAS were filled by participants to record shoulder pain and activity. Accelerometer data were processed to extract daily upper extremity activity in the form of active time; activity counts; and ratio of low-intensity activities, medium-intensity activities, and high-intensity activities.

RESULTS

Daily pain measured using VAS and SANE correlated well with the WORC and QuickDASH questionnaires (r=0.564-0.815) but not with accelerometry measures, amplitude, and strength. Daily activity measured with VAS had good correlation with active time (r=0.484, P=.02). All questionnaires had excellent test-retest reliability at 1 week before corticosteroid injections (intraclass correlation coefficient [ICC]=0.883-0.950). Acceptable reliability was observed with accelerometry (ICC=0.621-0.724), apart from low-intensity activities (ICC=0.104). Sensitivity to change was excellent at 2 and 4 weeks for all questionnaires (standardized response mean=1.039-2.094) except for activity VAS (standardized response mean=0.50). Accelerometry measures had low sensitivity to change at 2 weeks, but excellent sensitivity at 4 weeks (standardized response mean=0.803-1.032).

CONCLUSIONS

Daily pain VAS and SANE had good correlation with the validated questionnaires, excellent reliability at 1 week, and excellent sensitivity to change at 2 and 4 weeks. Daily activity VAS and accelerometry-derived active time correlated well together. Activity VAS had excellent reliability, but moderate sensitivity to change. Accelerometry measures had moderate reliability and acceptable sensitivity to change at 4 weeks.

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

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

A semiparametric model for wearable sensor-based physical activity monitoring data with informative device wear

Wearable sensors provide an exceptional opportunity in collecting real-time behavioral data in free living conditions. However, wearable sensor data from observational studies often suffer from information bias, since participants' willingness to wear the monitoring devices may be associated with the underlying behavior of interest. The aim of this study was to introduce a semiparametric statistical approach for modeling wearable sensor-based physical activity monitoring data with informative device wear. Our simulation study indicated that estimates from the generalized estimating equations showed ignorable bias when device wear patterns were independent of the participants physical activity process, but incrementally more biased when the patterns of device non-wear times were increasingly associated with the physical activity process. The estimates from the proposed semiparametric modeling approach were unbiased both when the device wear patterns were (i) independent or (ii) dependent to the underlying physical activity process. We demonstrate an application of this method using data from the 2003-2004 National Health and Nutrition Examination Survey ($N=4518$), to examine gender differences in physical activity measured using accelerometers. The semiparametric model can be implemented using our R package acc, free software developed for reading, processing, simulating, visualizing, and analyzing accelerometer data, publicly available at the Comprehensive R Archive Network.

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

BACKGROUND

Centrally acting medications cause cognitive slowing and incoordination, which could reduce older people's physical activity levels. This association has not been studied previously.

OBJECTIVES

The aim of this study was to examine the association between opioid, hypnotic and anticholinergic medication, and objectively measured physical activity, in a cohort of older people.

METHODS

We used data from the Physical Activity Cohort Scotland, a representative cohort of community-dwelling older people aged 65 years and over who were assessed at baseline and again 2-3 years later. Objective physical activity was measured using Stayhealthy RT3 accelerometers over 7 days. Baseline medication use (opioid use, hypnotic use, modified Anticholinergic Risk Scale [mARS]) was obtained from linked, routinely collected community prescribing records. Cross-sectional and longitudinal associations between baseline medication use and both baseline activity and change in activity over time were analysed using unadjusted and adjusted linear regression models.

RESULTS

Overall, 310 participants were included in the analysis; mean age 77 years (standard deviation 7). No association was seen between baseline use of any medication class and baseline physical activity levels in unadjusted or adjusted models. For change in activity over time, there was no difference between users and non-users of hypnotics or opioids. Higher anticholinergic burden was associated with a steeper decline in activity over the follow-up period (mARS 0: - 7051 counts/24 h/year; mARS 1-2: - 15,942 counts/24 h/year; mARS ≥ 3: - 19,544 counts/24 h/year; p = 0.03) and this remained robust to multiple adjustments.

CONCLUSION

Anticholinergic burden is associated with greater decline in objectively measured physical activity over time in older people, a finding not seen with hypnotic or opioid use.

Objective measurement of physical activity outcomes in lifestyle interventions among adults: A systematic review

Valid, reliable, and direct measures of physical activity (PA) are critical to assessing the impact of lifestyle PA interventions. However, little is known about the extent to which objective measures have been used to assess the outcomes of lifestyle PA interventions. This systematic review had two aims: 1) evaluate the extent to which PA is measured objectively in lifestyle PA interventions targeting adults and 2) explore and summarize what objective measures have been used and what PA dimensions and metrics have been reported. Pubmed, Cochrane Central Register, and PsychInfo were searched for lifestyle PA interventions conducted between 2006 and 2016. Of the 342 articles that met the inclusion criteria, 239 studies measured PA via subjective measures and 103 studies measured PA via objective measures. The proportion of studies using objective measures increased from 4.4% to 70.6% from 2006 to 2016. All studies measuring PA objectively utilized wearable devices; half (50.5%) used pedometers only and 40.8% used accelerometers only. A majority of the 103 studies reported steps (73.8%) as their PA metric. Incorporating objective measures of PA should continue to be a priority in PA research. More work is needed to address the challenges of comprehensive and consistent collecting, reporting, and analyzing of PA metrics.

Wearables in epilepsy and Parkinson's disease-A focus group study

OBJECTIVES

Wearable sensors that measure movement and physiological variables are attractive for clinical evaluation of neurological diseases such as epilepsy and Parkinson's disease (PD). The aim of this study was to explore perceptions regarding the use of wearable technology in disease monitoring and management as reported by individuals with epilepsy and Parkinson's disease as well as health professionals working with these patient groups.

MATERIALS AND METHODS

Six patient groups (n=25) and two groups with health professionals (n=15) participated in this qualitative, descriptive study with focus group interviews. A manifest qualitative content analysis was used.

RESULTS

Four categories and nine subcategories emerged from the analysis. Participants saw possible benefits for improved treatment effect and valued this benefit more than possible inconvenience of wearing the sensors. Discrete design and simplicity were considered as facilitators for improved usability. They emphasized the importance of interactive information between patients and health professionals. However, they were concerned about unclear information and inconclusive recordings and some fears about personal integrity were at odds with the expectations on interactivity.

CONCLUSIONS

Patients need to feel well informed and find an added value in using wearables. Wearables need to be user-friendly, have an attractive design, and show clinical efficacy in improving disease management. Variations in perceptions regarding integrity, benefits, and effectiveness of monitoring indicate possible conflicts of expectations among participants. The engagement of end users, patients, and health professionals, in the design and implementation process, is crucial for the development of wearable devices that enhance and facilitate neurological rehabilitation practice.

Qualitative ergonomics/human factors research in health care: Current state and future directions

The objective of this systematic review was to understand the current state of Ergonomics/Human Factors (E/HF) qualitative research in health care and to draw implications for future efforts. This systematic review identified 98 qualitative research papers published between January 2005 and August 2015 in the seven journals endorsed by the International Ergonomics Association with an impact factor over 1.0. The majority of the studies were conducted in hospitals and outpatient clinics, were focused on the work of formal health care professionals, and were classified as cognitive or organizational ergonomics. Interviews, focus groups, and observations were the most prevalent forms of data collection. Triangulation and data archiving were the dominant approaches to ensuring rigor. Few studies employed a formal approach to qualitative inquiry. Significant opportunities remain to enhance the use of qualitative research to advance systems thinking within health care.

Understanding Environmental and Contextual Influences of Physical Activity During First-Year University: The Feasibility of Using Ecological Momentary Assessment in the MovingU Study

BACKGROUND

It is well established that drastic declines in physical activity (PA) occur during young adults' transition into university; however, our understanding of contextual and environmental factors as it relates to young adults' PA is limited.

OBJECTIVE

The purpose of our study was to examine the feasibility of using wrist-worn accelerometers and the use of ecological momentary assessment (EMA) to assess the context and momentary correlates of PA on multiple occasions each day during first-year university.

METHODS

First-year university students were asked to participate in the study. The participants completed a brief questionnaire and were subsequently asked to wear an ActiGraph GT9X-Link accelerometer and respond to a series of EMA prompts (7/day) via their phones for 5 consecutive days.

RESULTS

A total of 96 first-year university students with smartphones agreed to participate in the study (mean age 18.3 [SD 0.51]; n=45 females). Overall, there was good compliance for wearing the accelerometers, with 91% (78/86) of the participants having ≥2 days of ≥10 hours of wear time (mean=3.53 valid days). Students were generally active, averaging 10,895 steps/day (SD 3413) or 1123.23 activity counts/min (SD 356.10). Compliance to EMA prompts was less desirable, with 64% (55/86) of the participants having usable EMA data (responding to a minimum of ≥3 days of 3 prompts/day or ≥4 days of 2 prompts/day), and only 47% (26/55) of these participants were considered to have excellent EMA compliance (responding to ≥5 days of 4 prompts/day or ≥ 4 days of 5 prompts/day).

CONCLUSIONS

This study represents one of the first studies to use an intensive real-time data capture strategy to examine time-varying correlates of PA among first-year university students. These data will aim to describe the physical and social contexts in which PA occurs and examine the relationships between momentary correlates of PA among the first-year university students. Overall, current results suggest that wrist-worn accelerometers and EMA are feasible methods for data collection among the young adult population; however, more work is needed to understand how to improve upon compliance to a real-time data capture method such as EMA.

Accelerometer-based measures in physical activity surveillance: current practices and issues

OBJECTIVE

Self-reports of physical activity (PA) have been the mainstay of measurement in most non-communicable disease (NCD) surveillance systems. To these, other measures are added to summate to a comprehensive PA surveillance system. Recently, some national NCD surveillance systems have started using accelerometers as a measure of PA. The purpose of this paper was specifically to appraise the suitability and role of accelerometers for population-level PA surveillance.

METHODS

A thorough literature search was conducted to examine aspects of the generalisability, reliability, validity, comprehensiveness and between-study comparability of accelerometer estimates, and to gauge the simplicity, cost-effectiveness, adaptability and sustainability of their use in NCD surveillance.

CONCLUSIONS

Accelerometer data collected in PA surveillance systems may not provide estimates that are generalisable to the target population. Accelerometer-based estimates have adequate reliability for PA surveillance, but there are still several issues associated with their validity. Accelerometer-based prevalence estimates are largely dependent on the investigators' choice of intensity cut-off points. Maintaining standardised accelerometer data collections in long-term PA surveillance systems is difficult, which may cause discontinuity in time-trend data. The use of accelerometers does not necessarily produce useful between-study and international comparisons due to lack of standardisation of data collection and processing methods. To conclude, it appears that accelerometers still have limitations regarding generalisability, validity, comprehensiveness, simplicity, affordability, adaptability, between-study comparability and sustainability. Therefore, given the current evidence, it seems that the widespread adoption of accelerometers specifically for large-scale PA surveillance systems may be premature.

The effectiveness of a lumbopelvic monitor and feedback device to change postural behavior: a feasibility randomized controlled trial

STUDY DESIGN

Feasibility randomized controlled trial.

OBJECTIVES

To assess the feasibility of a trial to investigate the effectiveness of a lumbopelvic monitor as a feedback device for modifying postural behavior during daily work-related activities.

BACKGROUND

Frequent or sustained flexed postures play a role in the development or maintenance of nonspecific low back pain. The provision of postural feedback could help individuals with or at risk of nonspecific low back pain improve their postural awareness and avoid hazardous or pain-provoking postures.

METHODS

Sixty-two participants employed in a health care organization were randomly allocated into 1 of 3 groups: a control group, an intermittent feedback group, and a constant feedback group. Adherence and follow-up rates were assessed. Differences in postural pattern between baseline and follow-up measurements were used to assess the effectiveness of the lumbopelvic monitor as a postural feedback device.

RESULTS

Adherence was approximately 75%. With the exception of 1 center, the follow-up overall rates exceeded the a priori desired threshold of 80%. Within-group comparisons revealed no significant differences in postural pattern for the control group and intermittent feedback group. The constant feedback group showed a significant reduction in flexed posture at the follow-up period compared with the baseline period. Differences between groups did not reach statistical significance; however, the constant feedback group, compared with the control group, demonstrated an effect size (d) of 0.60.

CONCLUSION

The provision of constant postural feedback seems promising for promoting changes in postural behavior. This feasibility trial identified adherence and follow-up rates and sample-size estimates important to the conduct of a fully powered efficacy trial. Level of Evidence Therapy, level 2b-.

Pedometer-driven walking for chronic low back pain: a feasibility randomized controlled trial

OBJECTIVES

To evaluate the feasibility of an RCT of a pedometer-driven walking program and education/advice to remain active compared with education/advice only for treatment of chronic low back pain (CLBP).

METHODS

Fifty-seven participants with CLBP recruited from primary care were randomly allocated to either: (1) education/advice (E, n=17) or (2) education/advice plus an 8-week pedometer-driven walking program (EWP, n=40). Step targets, actual daily step counts, and adverse events were recorded in a walking diary over the 8 weeks of intervention for the EWP group only. All other outcomes (eg, functional disability using the Oswestry Disability Questionnaire (ODQ), pain scores, physical activity (PA) measurement etc.) were recorded at baseline, week 9 (immediately post-intervention), and 6 months in both groups.

RESULTS

The recruitment rate was 22% and the dropout rate was lower than anticipated (13% to 18% at 6 mo). Adherence with the EWP was high, 93% (n=37/40) walked for ≥ 6 weeks, and increased their steps/day (mean absolute increase in steps/d, 2776, 95% confidence interval [CI], 1996-3557) by 59% (95% CI, 40.73%-76.25%) from baseline. Mean percentage adherence with weekly step targets was 70% (95% CI, 62%-77%). Eight (20%) minor-related adverse events were observed in 13% (5/40) of the participants. The EWP group participants demonstrated an 8.2% point improvement (95% CI, -13 to -3.4) on the ODQ at 6 months compared with 1.6% points (95% CI, -9.3 to 6.1) for the E group (between group d=0.44). There was also a larger mean improvement in pain (d=0.4) and a larger increase in PA (d=0.59) at 6 months in EWP.

DISCUSSION

This preliminary study demonstrated that a main RCT is feasible. EWP was safe and produced a real increase in walking; CLBP function and pain improved, and participants perceived a greater improvement in their PA levels. These improvements require confirmation in a fully powered RCT.

Optimal sensor placement for measuring physical activity with a 3D accelerometer

Accelerometer-based activity monitors are popular for monitoring physical activity. In this study, we investigated optimal sensor placement for increasing the quality of studies that utilize accelerometer data to assess physical activity. We performed a two-staged study, focused on sensor location and type of mounting. Ten subjects walked at various walking speeds on a treadmill, performed a deskwork protocol, and walked on level ground, while simultaneously wearing five ProMove2 sensors with a snug fit on an elastic waist belt. We found that sensor location, type of activity, and their interaction-effect affected sensor output. The most lateral positions on the waist belt were the least sensitive for interference. The effect of mounting was explored, by making two subjects repeat the experimental protocol with sensors more loosely fitted to the elastic belt. The loose fit resulted in lower sensor output, except for the deskwork protocol, where output was higher. In order to increase the reliability and to reduce the variability of sensor output, researchers should place activity sensors on the most lateral position of a participant's waist belt. If the sensor hampers free movement, it may be positioned slightly more forward on the belt. Finally, sensors should be fitted tightly to the body.

Combining self-help and professional help to minimize barriers to physical activity in persons with multiple sclerosis: a trial of the "Blue Prescription" approach in New Zealand

BACKGROUND AND PURPOSE

Increasing participation in physical activity is a goal for many health care providers working with persons with disability. In order to reduce the physical and social barriers to participation, there is a need to develop approaches that integrate self-help with professional help for autonomous yet supported health promotion. This study reports on an innovative program, entitled the "Blue Prescription approach", in which physical therapists work collaboratively with persons with a disability to promote community-based physical activity participation.

METHODS

We trialed this collaborative approach with two physical therapists and 27 participants with multiple sclerosis (MS) over a three month period. We gathered qualitative data from four sources: (i) individual interviews with our participants, (ii) individual interviews with the physical therapists, (iii) clinical notes, and (iv) Advisory Group meeting notes. We then analyzed these data for categories to inform the content and resources required for delivery of the approach.

RESULTS

For most participants, the Blue Prescription approach facilitated regular engagement in the physical activity of their choice. The Advisory Group provided advice to help solve individual contexts that presented as challenges to participants. Based on review of interview transcripts, we identified four strategies or issues to inform the further development of Blue Prescription.

DISCUSSION AND CONCLUSIONS

Evidence indicated that the Blue Prescription approach can provide a collaborative and flexible way for physical therapists to work with individuals with MS, to increase participation in community-based physical activity. To further develop the approach, there is a need to address issues related to the use of standardized measures and develop strategies to train physical therapists in collaborative approaches for promotion of physical activity.The integration of self-help and professional help provided by the Blue Prescription approach appeared to result in successful promotion of physical activity in persons with MS. Additional testing is required to examine its efficacy in other health care systems, in conditions beyond MS, and in terms of its economic impact.Video Abstract available (see Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A46) for more insights from the authors.

Self-reported versus objectively assessed exercise adherence

OBJECTIVE. We examined agreement of data between self-reported and objectively assessed exercise adherence among women with systemic lupus erythematosus. METHOD. Eleven participants completed weekly exercise logs on date and duration of exercise during a 10-wk Wii Fit™ home-based program. Afterward, exercise data from the log were compared with those recorded in the Wii console. RESULTS. Of the paired data, the mean duration of exercise recorded in the Wii was 29.5 min and that recorded in the log was 33.3 min. The composite intraclass correlation for exercise duration between exercise log and the Wii Fit was 0.4. The 95% limits of agreement indicated large between-subjects variability. CONCLUSION. Exercise logs exhibit a marginally acceptable agreement with Wii estimation of exercise duration at a group level. However, caution should be applied when using the exercise log as a measure of a person's exercise behavior because of the tendency to overreport.

Factors associated with participant compliance in studies using accelerometers

Participant compliance is an important issue in studies using accelerometers. Some participants wear the accelerometer for the duration specified by the researchers but many do not. We investigated a range of demographic factors associated with participant compliance in obtaining analyzable accelerometer data. A total of 3601 participants (aged 47.6±13.1 years, 44.6% male) were included. They were asked to wear an accelerometer (ActiGraph) for four consecutive days after completing a household survey during March 2009-January 2011 in Hong Kong. Participants wore the accelerometer on average for 13.9h in a 24-h day. No significant difference was found between males and females (p=0.38). Using log-linear regression, it was found that older participants (0.5% more wearing hours for each year of age, p<0.001), those with full-time job (p<0.01), with tertiary education (p<0.01), non-smokers (p<0.01) and with high self-reported health (p<0.05) wore the accelerometer for more hours. These results provide details for estimating compliance rates for samples with different characteristics and thus sample size calculation to account for participant compliance.

Is the pain of activity log-books worth the gain in precision when distinguishing wear and non-wear time for tri-axial accelerometers?

OBJECTIVE

To compare three methods for assessing wear time from accelerometer data: automated, log-books and a combination of the two.

DESIGN

Cross-sectional study.

METHODS

Forty-five office workers wore an Actigraph GT3X accelerometer and kept a detailed activity log-book for 7 days. The automated method used six algorithms to determine non-wear time (20, 60, or 90 min of consecutive zero counts with and without 2-min interruptions); the log-book method used participant recorded on/off times; the combined method used the 60-min automated filter (with ≤2 min interruptions) plus detailed log-book data. Outcomes were number of participants with valid data, number of valid days, estimates of wear time and time spent in sedentary, light, moderate and vigorous activity. Percentage misclassification, sensitivity, specificity, and area under the receiver-operating curve were compared for each method, with the combined method as the reference.

RESULTS

Using the combined method, 34 participants met criteria for valid wear time (≥10 h/day, ≥4 days). Mean wear times ranged from 891 to 925 min/day and mean sedentary time s from 438 to 490 min/day. Percentage misclassification was higher and area under the receiver-operating curve was lower for the log-book method than for the automated methods. Percentage misclassification was lowest and area under the receiver-operating curve highest for the 20-min filter without interruptions, but this method had fewer valid days and participants than the 60 and 90-min filters without interruptions.

CONCLUSIONS

Automated filters are as accurate as a combination of automated filters and log-books for filtering wear time from accelerometer data. Automated filters based on 90-min of consecutive zero counts without interruptions are recommended for future studies.

Young People's Views on Accelerometer Use in Physical Activity Research: Findings from a User Involvement Investigation

The use of accelerometers to objectively measure physical activity is important in understanding young people's behaviours, as physical activity plays a key part in obesity prevention and treatment. A user-involvement qualitative study with young people aged 7–18 years (n = 35) was carried out to investigate views on accelerometer use to inform an obesity treatment research study. First impressions were often negative, with issues related to size and comfort reported. Unwanted attention from wearing an accelerometer and bullying risk were also noted. Other disadvantages included feeling embarrassed and not being able to wear the device for certain activities. Positive aspects included feeling “special” and having increased attention from friends. Views on the best time to wear accelerometers were mixed. Advice was offered on how to make accelerometers more appealing, including presenting them in a positive way, using a clip rather than elastic belt to attach, personalising the device, and having feedback on activity levels. Judgements over the way in which accelerometers are used should be made at the study development stage and based on the individual population. In particular, introducing accelerometers in a clear and positive way is important. Including a trial wearing period, considering practical issues, and providing incentives may help increase compliance.

The pathogenesis of degeneration of the intervertebral disc and emerging therapies in the management of back pain

This article reviews the current knowledge of the intervertebral disc (IVD) and its association with low back pain (LBP). The normal IVD is a largely avascular and aneural structure with a high water content, its nutrients mainly diffusing through the end plates. IVD degeneration occurs when its cells die or become dysfunctional, notably in an acidic environment. In the process of degeneration, the IVD becomes dehydrated and vascularised, and there is an ingrowth of nerves. Although not universally the case, the altered physiology of the IVD is believed to precede or be associated with many clinical symptoms or conditions including low back and/or lower limb pain, paraesthesia, spinal stenosis and disc herniation.

New treatment options have been developed in recent years. These include biological therapies and novel surgical techniques (such as total disc replacement), although many of these are still in their experimental phase. Central to developing further methods of treatment is the need for effective ways in which to assess patients and measure their outcomes. However, significant difficulties remain and it is therefore an appropriate time to be further investigating the scientific basis of and treatment of LBP.

Validity of combining heart rate and uniaxial acceleration to measure free-living physical activity energy expenditure in young men

Combining accelerometry (ACC) with heart rate (HR) monitoring is thought to improve activity energy expenditure (AEE) estimations compared with ACC alone to evaluate the validity of ACC and HR used alone or combined. The purpose of this study was to estimate AEE in free-living conditions compared with doubly labeled water (DLW). Ten-day free-living AEE was measured by a DLW protocol in 35 18- to 55-yr-old men (11 lean active; 12 lean sedentary; 12 overweight sedentary) wearing an Actiheart (combining ACC and HR) and a RT3 accelerometer. AEE was estimated using group or individual calibration of the HR/AEE relationship, based on an exercise-tolerance test. In a subset (n = 21), AEE changes (ΔAEE) were measured after 1 mo of detraining (active subjects) or an 8-wk training (sedentary subjects). Actiheart-combined ACC/HR estimates were more accurate than estimates from HR or ACC alone. Accuracy of the Actiheart group-calibrated ACC/HR estimates was modest [intraclass correlation coefficient (ICC) = 0.62], with no bias but high root mean square error (RMSE) and limits of agreement (LOA). The mean bias of the estimates was reduced by one-third, like RMSE and LOA, by individual calibration (ICC = 0.81). Contrasting with group-calibrated estimates, the Actiheart individual-calibrated ACC/HR estimates explained 40% of the variance of the DLW-ΔAEE (ICC = 0.63). This study supports a good level of agreement between the Actiheart ACC/HR estimates and DLW-measured AEE in lean and overweight men with varying fitness levels. Individual calibration of the HR/AEE relationship is necessary for AEE estimations at an individual level rather than at group scale and for ΔAEE evaluation.

Variability in physical activity patterns as measured by the SenseWear Armband: how many days are needed?

To examine sources of variance in objectively measured physical activity and to determine the number of monitoring days needed to quantify physical activity patterns reliably, 394 Flemish adults (41.1 ± 9.9 years) were monitored during 7 days, using the SenseWear Armband. Differences between weekdays, Saturday and Sunday were examined with repeated measures ANOVA's. Variance components were estimated for subject, weekday and residual error using data from Mondays through Fridays and used to calculate the reliability of 1-5 monitoring weekdays. Saturday was more and Sunday less active than an average weekday. Inter-individual variability was the largest source of variance (54.4-67.9%) for physical activity level (PAL), energy expenditure, inactivity, light, moderate and total physical activity. Intra-individual variability accounted for 31.8-44.8% and weekday for 0.1-1.1% of total variance. Intra-individual variability was the largest source of variance for vigorous activity in both sexes and steps in women. At least, 3 monitoring weekdays were required to achieve a reliability of 0.80 for PAL, energy expenditure, inactivity, light, moderate and total physical activity. All 5 weekdays should be monitored to reach acceptable reliability for steps. Five weekdays resulted in a reliability of 0.58-0.60 for vigorous activity. Both Saturday and Sunday and at least 3 weekdays need to be monitored to obtain reliable measures of habitual physical activity.

Utility of accelerometers to measure physical activity in children attending an obesity treatment intervention

Objectives. To investigate the use of accelerometers to monitor change in physical activity in a childhood obesity treatment intervention. Methods. 28 children aged 7-13 taking part in "Families for Health" were asked to wear an accelerometer (Actigraph) for 7-days, and complete an accompanying activity diary, at baseline, 3-months and 9-months. Interviews with 12 parents asked about research measurements. Results. Over 90% of children provided 4 days of accelerometer data, and around half of children provided 7 days. Adequately completed diaries were collected from 60% of children. Children partake in a wide range of physical activity which uniaxial monitors may undermonitor (cycling, nonmotorised scootering) or overmonitor (trampolining). Two different cutoffs (4 METS or 3200 counts·min(-1)) for minutes spent in moderate and vigorous physical activity (MVPA) yielded very different results, although reached the same conclusion regarding a lack of change in MVPA after the intervention. Some children were unwilling to wear accelerometers at school and during sport because they felt they put them at risk of stigma and bullying. Conclusion. Accelerometers are acceptable to a majority of children, although their use at school is problematic for some, but they may underestimate children's physical activity.

Integrated electronic platforms for weight loss

What can be done to build effective weight loss solutions for the 1.5 billion people with obesity? It is self-evident that no one good solution exists for people who are overweight or obese, otherwise it would have been applied across the people who need it worldwide. There is, therefore, an urgent need for approaches that will afford weight loss; what is more, such approaches need to be scalable. For that reason, it is attractive to consider electronic platforms as an avenue for scalable weight loss solutions. Such platforms often do not require substantial investments but rather the integration of pre-existing off-the-shelf components. In this article we explore the concepts and design challenges for electronic platforms that precipitate weight loss.