Utility of a step activity monitor for the measurement of daily ambulatory activity in children

Comparison of three device generations of the StepWatch Activity Monitor: analysis of model version agreement in pediatric and adult independent ambulators

Purpose

Devices such as the StepWatch Activity Monitor (SAM) have been available for 20 years and have been shown to accurately measure ambulatory activity. This study aimed to evaluate the agreement among the three generations of the StepWatch Activity Monitor (SW3, SW4, and SW5) with respect to stride count.

Methods

A total of 36 participants (age range, 6-55 years) participated in this institutional review board-approved study. The participants concurrently wore three different SAM model devices on the same leg and performed a 6-min walk test (6MWT). A research staff member of the laboratory manually counted the number of strides for the first 2 min of the test (2MWT). Agreement among the device models was evaluated by calculating ANOVAs and interclass correlation coefficients (ICCs) and creating Bland-Altman plots.

Results

There was no significant difference among the model versions during the 6MWT and 2MWT (p > 0.05). The ICC for the total stride count was 0.993 (95% CI = 0.988-0.996) during the 2MWT and 0.992 (95% CI = 0.986-0.996) during the 6MWT. There was a near-perfect agreement (ICC ≥ 0.990) of each model version to the manually counted strides during the 2MWT. The systematic bias of all three SAM model versions was <1 step.

Conclusions

The results from the present study demonstrate that the stride counts among all three devices are comparable and relative to the manual stride count. All three SAM model versions had an ICC of >0.90. Researchers can safely incorporate historical data from previous SAM model versions with newer data collected with the latest SAM model version.

Inclusive community playgrounds benefit typically developing children: An objective analysis of physical activity

Purpose

Limited research is available on the physical activity levels of children while playing on an inclusive playground, specifically designed to accommodate children with physical disabilities. The aims of this study were to objectively measure ambulatory activity and heart rate (HR) of children during unstructured play on an inclusive community playground.

Methods

Typically developing children at least 4 years of age were recruited to play freely upon entering the playground. Participants wore a StepWatch4 Activity Monitor and a Polar V800 Sport Watch. Ambulatory measures included total steps, percentage of recommended steps, total ambulatory time (TAT), bout intensity levels/duration periods. Time spent in HR zones and moderate-to-vigorous physical activity (MVPA) was determined.

Results

95 children (48 males; Avg. age: 7 ± 2 years.) were included in this study. Children played for 31.8 ± 14.7 min., were ambulatory for 25.9 ± 12.0 min., took 1826 ± 824 steps, and accumulated 17 ± 8% of the recommended daily step count. Ambulatory bout intensity was predominantly lower intensity and bout durations varied in length. 99% of the play time was spent at a moderate HR or higher. Significant correlations were found between ambulatory and HR measures (ρ range from 0.23 to 0.99, p < 0.05), and 7-10 yo children spent a significantly higher percentage of TAT at higher intensity ambulation (p < 0.05).

Conclusions

Typically developing children can achieve moderate or higher intensity exercise and HR on an inclusive playground. Both typically developing children and those with disabilities, would benefit from a setting where they can interact and participate in parallel play with their peers.

Comparison of Self-Reported vs Objective Measures of Long-Term Community Ambulation in Lower Limb Prosthesis Users

Objective

To determine normal variation in walking metrics in a population of lower limb amputees who use lower limb prostheses over a 6-month period and to provide a means to interpret clinically meaningful change in those community walking metrics.

Design

Prospective cohort study monitoring walking behavior and subjective and objective measures of activity.

Setting

Veterans Administration and university amputee clinics.

Participants

86 individuals with lower limb amputation who use protheses.

Interventions

StepWatch activity monitor tracked subjects’ walking for 24 weeks; Global Mobility Change Rating collected weekly.

Main Outcome Measures

Association between change in Global Mobility Change Rating and change in any of the walking metrics.

Results

Walking metrics including step count, cadence, cadence variability, and walking distance in a population of lower limb prosthesis users were obtained. There was a high correlation in the walking metrics indicating higher function with higher functional classification level (K-levels) but also substantial overlap in all metrics and a very weak correlation between subject-reported activity level and objective measures of walking performance.

Conclusion

The overlap in walking metrics with all K-levels demonstrates that no single metric measured by StepWatch can determine K-level with 100% accuracy. As previously demonstrated in other populations, subjects’ interpretations of their general activity level was inaccurate, regardless of their age or activity level. Objective measures of walking appear to provide a more accurate representation of patients’ activity levels in the community than self-report. Therefore, objective measures of walking are useful in supporting K-level determinations. However, clinicians cannot rely on a single metric to determine K-level.

Walking activity in a large cohort of boys with Duchenne muscular dystrophy

INTRODUCTION

In this study we explored walking activity in a large cohort of boys with Duchenne muscular dystrophy (DMD).

METHODS

Step activity (monitored for 7 days), functional ability, and strength were quantified in ambulatory boys (5-12.9 years of age) with DMD and unaffected boys. Ambulatory status was determined 2 years later.

RESULTS

Two to 5 days of activity monitoring predicted weekly step activity (adjusted R² = 0.80-0.95). Age comparisons revealed significant declines for step activity with increasing age, and relationships were found between step activity with both function and strength (P < .01). Our regression model predicted 36.5% of the variance in step activity. Those who were still ambulatory after 2 years demonstrated baseline step activity nearly double that of those who were no longer walking 2 years later (P < .01).

DISCUSSION

Step activity for DMD is related to and predictive of functional declines, which may be useful for clinical trials.

Machine Learning to Quantify Physical Activity in Children with Cerebral Palsy: Comparison of Group, Group-Personalized, and Fully-Personalized Activity Classification Models

Pattern recognition methodologies, such as those utilizing machine learning (ML) approaches, have the potential to improve the accuracy and versatility of accelerometer-based assessments of physical activity (PA). Children with cerebral palsy (CP) exhibit significant heterogeneity in relation to impairment and activity limitations; however, studies conducted to date have implemented “one-size fits all” group (G) models. Group-personalized (GP) models specific to the Gross Motor Function Classification (GMFCS) level and fully-personalized (FP) models trained on individual data may provide more accurate assessments of PA; however, these approaches have not been investigated in children with CP. In this study, 38 children classified at GMFCS I to III completed laboratory trials and a simulated free-living protocol while wearing an ActiGraph GT3X+ on the wrist, hip, and ankle. Activities were classified as sedentary, standing utilitarian movements, or walking. In the cross-validation, FP random forest classifiers (99.0–99.3%) exhibited a significantly higher accuracy than G (80.9–94.7%) and GP classifiers (78.7–94.1%), with the largest differential observed in children at GMFCS III. When evaluated under free-living conditions, all model types exhibited significant declines in accuracy, with FP models outperforming G and GP models in GMFCS levels I and II, but not III. Future studies should evaluate the comparative accuracy of personalized models trained on free-living accelerometer data.

Predictors of Walking Activity in Children and Adolescents With Myelomeningocele

OBJECTIVE

To assess the relationship between real-world walking activity in children and adolescents with myelomeningocele (MMC) and gross measures of lower extremity strength, range of motion, demographics, and medical history.

DESIGN

Prospective study.

SETTING

Participants recruited in outpatient clinics; data collected in a hospital-based motion analysis laboratory and in the community.

PARTICIPANTS

Children and adolescents (N=52) with daily step count data available from a larger study of ambulatory children and adolescents with MMC.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

Univariate and multivariate regression was used to assess which participant characteristics and clinical factors were related to average number of steps per day.

RESULTS

Univariate analysis showed a lower number of steps per day correlated with older age, male sex, higher body mass index, higher lesion level, use of assistive devices for ambulation, history of shunt placement, more television (TV) watched per week, lower hip extension and abduction strength, knee flexion strength, and ankle dorsiflexion and plantarflexion strength, and decreased knee and hip range of motion. Only assistive device usage and hours of TV watched per week remained in the final multivariate model predicting number of steps per day.

CONCLUSIONS

Walking activity in children and adolescents with MMC was best predicted by assistive device use and amount of sedentary activity. Other predictors of walking activity from univariate analysis were related to assistive device use. This information can help tailor rehabilitation efforts and educate patients and families. Interventions targeting early prevention of strength loss and contractures may be important to retain or increase walking activity in children and adolescents with MMC.

Video-Recorded Validation of Wearable Step Counters under Free-living Conditions

PURPOSE

The purpose of this study was to determine the accuracy of 14-step counting methods under free-living conditions.

METHODS

Twelve adults (mean ± SD age, 35 ± 13 yr) wore a chest harness that held a GoPro camera pointed down at the feet during all waking hours for 1 d. The GoPro continuously recorded video of all steps taken throughout the day. Simultaneously, participants wore two StepWatch (SW) devices on each ankle (all programmed with different settings), one activPAL on each thigh, four devices at the waist (Fitbit Zip, Yamax Digi-Walker SW-200, New Lifestyles NL-2000, and ActiGraph GT9X (AG)), and two devices on the dominant and nondominant wrists (Fitbit Charge and AG). The GoPro videos were downloaded to a computer and researchers counted steps using a hand tally device, which served as the criterion method.

RESULTS

The SW devices recorded between 95.3% and 102.8% of actual steps taken throughout the day (P > 0.05). Eleven step counting methods estimated less than 100% of actual steps; Fitbit Zip, Yamax Digi-Walker SW-200, and AG with the moving average vector magnitude algorithm on both wrists recorded 71% to 91% of steps (P > 0.05), whereas the activPAL, New Lifestyles NL-2000, and AG (without low-frequency extension (no-LFE), moving average vector magnitude) worn on the hip, and Fitbit Charge recorded 69% to 84% of steps (P < 0.05). Five methods estimated more than 100% of actual steps; AG (no-LFE) on both wrists recorded 109% to 122% of steps (P > 0.05), whereas the AG (LFE) on both wrists and the hip recorded 128% to 220% of steps (P < 0.05).

CONCLUSIONS

Across all waking hours of 1 d, step counts differ between devices. The SW, regardless of settings, was the most accurate method of counting steps.

Rehabilitation Management of the Patient With Duchenne Muscular Dystrophy

Steadily improving management of Duchenne muscular dystrophy (DMD) continues to lead to improved physical and functional status, allowing increasingly successful transitions to independence and self-actualization in adulthood. Rehabilitation principles remain key to overall management for individuals with DMD with increasing options for ever more successful management, reflecting a changing natural history based on the use of glucocorticoids, more consistent comprehensive care, and the emergence of disease-modifying treatments. Advances and expansion in assessment, cardiorespiratory management, preventive management of contracture and deformity, assistive technology, "smart" technology, and robotics with increased emphasis on function, participation, self-advocacy, and independence in decision-making should allow individuals with DMD to experience childhood and transition to adulthood with support that allows for increasing success in the achievement of individual goals and fulfillment across the life span.

Reliability of StepWatch Activity Monitor to Measure Locomotor Activity in Youth With Lower Limb Salvage

PURPOSE

The study purpose was to determine the minimum number of monitoring days necessary to reliably capture walking among individuals with lower limb salvage.

METHODS

Nineteen participants with lower limb salvage wore an ankle-mounted motion sensor over a 7-day period to obtain step counts. Generalizability theory was used to examine the variance components in step counts (G study) and to determine the appropriate length of activity monitoring using various combinations of days (D study).

RESULTS

Mean step counts were higher on weekends than on weekdays. Fifty percent of the total variance in step counts was accounted for by interindividual variability in walking (D study). Eighty percent was reached individually with 4 weekdays, 2 weekend days, or 3 week days + weekend days.

CONCLUSION

The study provides data for an appropriate monitoring method to track walking outcomes of rehabilitation for individuals with lower limb salvage.

Abdominal obesity adversely affects bone mass in children

AIM

To determine the effect of childhood obesity and insulin resistance on bone health.

METHODS

We conducted a cross sectional study in pubertal adolescents and young adults 13-20 years old who were either overweight/obese or normal weight. Participants were Tanner 3 or above for pubertal stage, and had fasting blood work done to measure glucose, insulin, C-reactive protein and lipid levels. Homeostatic model of insulin resistance (HOMA-IR) was calculated using the formula (Fasting Blood Glucose *Insulin/405). Body composition and bone mineral density were measured using dual energy X-ray absorptiometry (DXA; Hologic QDR 4500, Waltham, MA, United Kingdom).

RESULTS

Percent trunk fat was associated inversely with whole body bone mineral content (BMC), whereas HOMA-IR was associated positively with whole body BMC.

CONCLUSION

Our results suggest that abdominal adiposity may have an adverse effect on whole body bone parameters and that this effect is not mediated by insulin resistance.

Interval setting selection affects ambulatory activity outputs in children with cerebral palsy

INTRODUCTION

Accelerometer based devices have been widely used to assess the ambulatory activity of children with and without functional disabilities. Many researchers who utilize the StepWatch Activity Monitor (SAM) collect at a 60second (60sec) interval setting. The purpose of this study was to assess the effect of SAM interval settings on ambulatory activity outputs in children with cerebral palsy (CP) and typically developing youth.

METHODS

Participants wore a SAM which recorded the number of strides every 10seconds (10s) for one week. Raw 10s data was downsampled to combine strides into 60sec intervals. Strides were ensembled into walking bouts with the Intensity/Duration calculated as a percentage of Total Ambulatory Time (TAT).

RESULTS

Twenty-eight children with CP (14 boys; avg. 12 yrs. 4 mths.; GMFCS Level I n=4, Level II n=19, Level III n=5) completed testing and 28 age matched typically developing youth (14 boys; avg. 12 yrs. 6 mths.) were included. Using the 10sec interval, ∼80% of walking bouts in both groups were less than or equal to 60s. Data recorded at 60sec intervals had higher daily TAT but fewer walking bouts. In children with CP, daily steps were higher using the 60sec interval. At the Easy intensity, the 60sec interval reported an increased volume of Long duration walking, and it rarely identified any Moderate+ intensity activity.

CONCLUSIONS

60sec interval data overestimated low intensity and long duration ambulatory activity. It is imperative that investigators choose a finer interval setting (10sec) to maximize the detection of gait transitions and rest periods which are critical in describing community ambulation of patients with cerebral palsy.

Longitudinal community walking activity in Duchenne muscular dystrophy

INTRODUCTION

Natural history studies for Duchenne muscular dystrophy (DMD) have not included measures of community ambulation.

METHODS

Step activity (SA) monitors quantified community ambulation in 42 boys (ages 4-16 years) with DMD with serial enrollment up to 5 years by using a repeated-measures mixed model. Additionally, data were compared with 10-meter walk/run (10mWR) speed to determine validity and sensitivity.

RESULTS

There were significant declines in average strides/day and percent strides at moderate, high and pediatric high rates as a function of age (P < 0.05). Significant correlations for 10mWR versus high and low stride rates were found at baseline (P < 0.05). SA outcomes were sensitive to change over 1 year, but the direction and parameter differed by age group (younger vs. older). Changes in strides/day and percentages of high frequency and low frequency strides correlated significantly with changes in 10mWR speed (P < 0.05).

DISCUSSION

Community ambulation data provide valid and sensitive real-world measures that may inform clinical trials. Muscle Nerve 57: 401-406, 2018.

Objectively measured versus self-reported physical activity in children and adolescents with cancer

Objective

Existing research recognizes low levels of physical activity in pediatric patients with cancer, but much uncertainty exists about their capability to self-reflect physical activity levels. The objective of this study was to compare results of subjective self-reports and objective accelerometers regarding levels of daily walking as well as moderate-to-vigorous physical activities.

Methods

Results of the objective assessment tool StepWatchTM Activity Monitor and self-reporting with a standardized questionnaire were compared in 28 children and adolescents during cancer treatment.

Results

The patients were 13.8±2.8 years of age and 3.4±2.0 months after cancer diagnosis. The Bland-Altman plots indicated a fairly symmetrical under- and over-estimation for daily minutes of walking with the limits of agreement ranging from -100.8 to 87.3 min (d = -6.7 min). Mean difference for moderate-to-vigorous physical activity was almost zero but limits of agreement are ranging from -126.8 to 126.9 min. The comparison for the days with at least 60 min of moderate-to-vigorous physical activity showed a marked difference with 3.0±2.6 self-reported days versus only 0.1±0.4 measured days.

Conclusions

These findings suggest that physical activity in pediatric cancer patients should preferably be assessed with objective methods. Greater efforts are needed to implement supervised exercise interventions during treatment incorporating methods to improve self-reflection of physical activity.

Domains of Daily Physical Activity in Children with Mitochondrial Disease: A 3D Accelerometry Approach

Feasible, sensitive and clinically relevant outcome measures are of extreme importance when designing clinical trials. For paediatric mitochondrial disease, no robust end point has been described to date. The aim of this study was to select the domains of daily physical activity, which can be measured by 3D accelerometry, that could serve as sensitive end points in future clinical trials in children with mitochondrial disorders.In this exploratory observational study, 17 patients with mitochondrial disease and 16 age- and sex-matched controls wore 3D accelerometers at the upper leg, upper arm, lower arm and chest during one weekend. Using the raw data obtained by the accelerometers, we calculated the following outcome measures: (1) average amount of counts per hour the sensors were worn; (2) the maximal intensity; (3) the largest area under the curve during 30 min and (4) categorized activities lying, standing or being dynamically active. Measuring physical activity during the whole weekend was practically feasible in all participants. We found good face validity by visually correlating the validation videos and activity diaries to the accelerometer data-graphs. Patients with mitochondrial disorders had significantly lower peak intensity and were resting more, compared to their age- and sex-matched peers.Finally, we suggest domains of physical activity that could be included when measuring daily physical activity in children with mitochondrial disorders, preferably using more user-friendly devices. These include peak activity parameters for the arms (all patients) and legs (ambulatory patients). We recommend using or developing devices that measure these domains of physical activity in future clinical studies.

Measuring Habitual Physical Activity in Neuromuscular Disorders: A Systematic Review

BACKGROUND

Free-living or habitual physical activity (HPA) refers to someone's performance in his or her free-living environment. Neuromuscular disorders (NMD) manifest through HPA, and the observation of HPA can be used to identify clinical risks and to quantify outcomes in research. This review summarizes and analyses previous studies reporting the assessment of HPA in NMD, and may serve as the basis for evidence-based decision-making when considering assessing HPA in this population.

METHODS

A systematic review was performed to identify all studies related to HPA in NMD, followed by a critical appraisal of the assessment methodology and a final review of the identified HPA tools.

RESULTS

A total of 22 studies were selected, reporting on eight different direct tools (or activity monitors) and ten structured patient-reported outcomes. Overall, HPA patterns in NMD differ from healthy control populations. There was a noticeable lack of validation studies for these tools and outcome measures in NMD. Very little information regarding feasibility and barriers for the application of these tools in this population have been published.

CONCLUSIONS

The variety and heterogeneity of tools and methods in the published literature makes the comparison across different studies difficult, and methodological guidelines are warranted. We propose a checklist of considerations for the assessment and reporting of HPA in NMD.

Residual limb skin temperature and thermal comfort in people with amputation during activity in a cold environment

Thermal comfort remains a common problem for people with lower-limb amputation. Both donning a prosthesis and engaging in activity at room temperature can increase residual limb skin temperature; however, the effects of activity on skin temperature and comfort in more extreme environments remain unknown. We examined residual limb skin temperatures and perceived thermal comfort (PTC; 11-point Likert scale) of participants with unilateral transtibial amputation (n = 8) who were snowshoeing in a cold environment. Residual limb skin temperature increased by 3.9°C [3.0°C to 4.7°C] (mean difference [95% confidence interval (CI)], p < 0.001) after two 30 min exercise sessions separated by a 5 min rest session. Minimal cooling (-0.2°C [-1.1°C to 0.6°C]) occurred during the rest period. Similar changes in PTC were found for the residual limb, intact limb, and whole body, with a mean scale increase of 1.6 [1.1 to 2.1] and 1.3 [0.8 to 1.8] for the first and second exercise sessions, respectively (p < 0.001). Activity in a cold environment caused similar increases in residual limb skin temperature as those found in studies conducted at room temperature. Participants with amputation perceived warming as their skin temperature increased during exercise followed by the perception of cooling during rest, despite minimal associated decreases in skin temperature.

Walking activity during daily living in children with myelomeningocele

PURPOSE

To quantify the walking activity of children with myelomeningocele during daily living.

METHOD

Walking activity was measured using a StepWatch activity monitor over one week in 47 children with myelomeningocele (27 males; 9 years 11 months SD 2 years 7 months; 18 sacral, 9 low lumbar, 20 mid-high lumbar) and seven children with typical development (5 males; 11 years 1 month SD 1 year 11 months) in a prospective, cross-sectional study. Average total steps per day, number of steps and minutes spent at low, medium and high intensity stepping were evaluated. Groups were compared using t-tests and chi-squared tests with Bonferroni post-hoc adjustment.

RESULTS

Children with sacral and low lumbar myelomeningocele exhibited no significant differences in demographic characteristics or walking performance compared to typically developing children. Children with mid-high lumbar myelomeningocele exhibited higher BMI percentile than the control group (p = 0.04) and took fewer total steps per day than all other groups (p ≤ 0.04). Children with mid-high lumbar myelomeningocele also spent significantly less time taking steps at all intensity levels, particularly medium-intensity, than the sacral and low lumbar groups (p ≤ 0.04).

CONCLUSIONS

Children with sacral and low lumbar myelomeningocele had walking performance similar to typically developing children despite a common need for braces and assistive devices. Children with mid-high lumbar myelomeningocele were less active, which may lead to heightened risk for secondary health conditions in addition to those associated with myelomeningocele. Implications for Rehabilitation Obesity, muscle weakening and disuse osteoporosis are issues for those with myelomeningocele, all of which are affected by walking activity. Understanding walking activity and intensity in children and adolescents with myelomeningocele may aid in developing focused rehabilitation interventions and strategies. Real world walking activity as an objective and quantified measure has the potential to help guide therapists and surgeons to more effective treatments.

A Movement Monitor Based on Magneto-Inertial Sensors for Non-Ambulant Patients with Duchenne Muscular Dystrophy: A Pilot Study in Controlled Environment

Measurement of muscle strength and activity of upper limbs of non-ambulant patients with neuromuscular diseases is a major challenge. ActiMyo^® is an innovative device that uses magneto-inertial sensors to record angular velocities and linear accelerations that can be used over long periods of time in the home environment. The device was designed to insure long-term stability and good signal to noise ratio, even for very weak movements. In order to determine relevant and pertinent clinical variables with potential for use as outcome measures in clinical trials or to guide therapy decisions, we performed a pilot study in non-ambulant neuromuscular patients. We report here data from seven Duchenne Muscular Dystrophy (DMD) patients (mean age 18.5 ± 5.5 years) collected in a clinical setting. Patients were assessed while wearing the device during performance of validated tasks (MoviPlate, Box and Block test and Minnesota test) and tasks mimicking daily living. The ActiMyo^® sensors were placed on the wrists during all the tests. Software designed for use with the device computed several variables to qualify and quantify muscular activity in the non-ambulant subjects. Four variables representative of upper limb activity were studied: the rotation rate, the ratio of the vertical component in the overall acceleration, the hand elevation rate, and an estimate of the power of the upper limb. The correlations between clinical data and physical activity and the ActiMyo^® movement parameters were analyzed. The mean of the rotation rate and mean of the elevation rate appeared promising since these variables had the best reliability scores and correlations with task scores. Parameters could be computed even in a patient with a Brooke functional score of 6. The variables chosen are good candidates as potential outcome measures in non-ambulant patients with Duchenne Muscular Dystrophy and use of the ActiMyo^® is currently being explored in home environment.

Trial Registration: ClinicalTrials.gov NCT01611597

An individual approach for optimizing ankle-foot orthoses to improve mobility in children with spastic cerebral palsy walking with excessive knee flexion

Ankle-Foot Orthoses (AFOs) are commonly prescribed to promote gait in children with cerebral palsy (CP). The AFO prescription process is however largely dependent on clinical experience, resulting in confusing results regarding treatment efficacy. To maximize efficacy, the AFO's mechanical properties should be tuned to the patient's underlying impairments. This study aimed to investigate whether the efficacy of a ventral shell AFO (vAFO) to reduce knee flexion and walking energy cost could be improved by individually optimizing AFO stiffness in children with CP walking with excessive knee flexion. Secondarily, the effect of the optimized vAFO on daily walking activity was investigated. Fifteen children with spastic CP were prescribed with a hinged vAFO with adjustable stiffness. Effects of a rigid, stiff, and flexible setting on knee angle and the net energy cost (EC) [Jkg(-1)m(-1)] were assessed to individually select the optimal stiffness. After three months, net EC, daily walking activity [stridesmin(-1)] and knee angle [deg] while walking with the optimized vAFO were compared to walking with shoes-only. A near significant 9% (p=0.077) decrease in net EC (-0.5Jkg(-1)m(-1)) was found for walking with the optimized vAFO compared to shoes-only. Daily activity remained unchanged. Knee flexion in stance was reduced by 2.4° (p=0.006). These results show that children with CP who walk with excessive knee flexion show a small, but significant reduction of knee flexion in stance as a result of wearing individually optimized vAFOs. Data suggest that this also improves gait efficiency for which an individual approach to AFO prescription is emphasized.

Physical activity and health-related quality of life in pediatric cancer patients following a 4-week inpatient rehabilitation program

PURPOSE

Chronic health conditions and impaired quality of life are commonly experienced in childhood cancer survivors. While rehabilitation clinics support patients in coping with the disease, studies evaluating an inpatient rehabilitation program on promoting physical activity (PA) and health-related quality of life (HRQoL) are missing.

METHODS

A 4-week inpatient rehabilitation program was prospectively evaluated. One hundred fifty patients with leukemia or lymphoma (N = 86), brain tumors (N = 38), and sarcomas (N = 26) were enrolled on average 17 months after cessation of acute medical treatment. PA amount and cadence (indicating the intensity of walking activity) using the StepWatch™ 3 Activity Monitor and HRQoL global and physical well-being scores using the KINDL(®) questionnaire were assessed before, immediately after, and 6 and 12 months following the program and analyzed using multiple linear mixed models.

RESULTS

Significant effects on PA were only found at 12-month follow-up for amount and cadence variables (all p < 0.05). While leukemia and lymphoma patients revealed the highest PA level throughout the study, rehabilitation effects were more pronounced for cadence variables in brain tumor and sarcoma patients. The rehabilitation program had immediate (t = 4.56, p < 0.001) and sustainable effects on HRQoL global scores (6-month follow-up, t = 4.08, p < 0.001; 12-month follow-up, t = 3.13, p < 0.006).

CONCLUSIONS

Immediate and sustainable increases in HRQoL indicate that a 4-week rehabilitation program is beneficial for improving psychosocial well-being, while the significant increase in PA levels could be related to general recovery as well. The lack of a control group hampers the evaluation of the rehabilitation program on promoting PA levels in pediatric cancer patients.

Physical activity and health-related quality of life in pediatric cancer patients following a 4-week inpatient rehabilitation program

PURPOSE

Chronic health conditions and impaired quality of life are commonly experienced in childhood cancer survivors. While rehabilitation clinics support patients in coping with the disease, studies evaluating an inpatient rehabilitation program on promoting physical activity (PA) and health-related quality of life (HRQoL) are missing.

METHODS

A 4-week inpatient rehabilitation program was prospectively evaluated. One hundred fifty patients with leukemia or lymphoma (N = 86), brain tumors (N = 38), and sarcomas (N = 26) were enrolled on average 17 months after cessation of acute medical treatment. PA amount and cadence (indicating the intensity of walking activity) using the StepWatch™ 3 Activity Monitor and HRQoL global and physical well-being scores using the KINDL(®) questionnaire were assessed before, immediately after, and 6 and 12 months following the program and analyzed using multiple linear mixed models.

RESULTS

Significant effects on PA were only found at 12-month follow-up for amount and cadence variables (all p < 0.05). While leukemia and lymphoma patients revealed the highest PA level throughout the study, rehabilitation effects were more pronounced for cadence variables in brain tumor and sarcoma patients. The rehabilitation program had immediate (t = 4.56, p < 0.001) and sustainable effects on HRQoL global scores (6-month follow-up, t = 4.08, p < 0.001; 12-month follow-up, t = 3.13, p < 0.006).

CONCLUSIONS

Immediate and sustainable increases in HRQoL indicate that a 4-week rehabilitation program is beneficial for improving psychosocial well-being, while the significant increase in PA levels could be related to general recovery as well. The lack of a control group hampers the evaluation of the rehabilitation program on promoting PA levels in pediatric cancer patients.

Functional level assessment of individuals with transtibial limb loss: Evaluation in the clinical setting versus objective community ambulatory activity

The functional level (K level) of prosthetic users is used to choose appropriate prosthetic components, but ratings may highly subjective. A more objective and robust method to determine K level may be appealing. The aim of this study was to determine the relationship between K level determined in the clinic to K level based on real world ambulatory activity data collected by StepWatch. Twelve individuals with transtibial limb loss gave informed consent to participate. K level assessments performed in the clinic by a single treating prosthetist were compared with a calculated estimate based on seven days of real world ambulatory activity patterns using linear regression. There was good agreement between the two methods of determining K level with R²= 0.775 (p < 0.001). The calculated estimate of K level based on actual ambulatory activity in real world settings appears to be similar to the treating prosthetist’s assessment of K level based on gait observation and patient responses in the clinic. Clinic-based ambulatory capacity in transtibial prosthetic users appears to correlate with real world ambulatory behavior in this small cohort. Determining functional level based on real world ambulatory activity may supplement clinic-based tests of functional capacity.

Comparison of prosthetic outcomes between adolescent transtibial and transfemoral amputees after Sichuan earthquake using Step Activity Monitor and Prosthesis Evaluation Questionnaire

BACKGROUND

The devastating earthquake in Sichuan in 2008 has left many adolescent amputees. However, little research has been focused on the adolescent amputees who have high potential to return to premorbid activity level.

OBJECTIVES

To investigate daily step activities and prosthesis-related quality of life of the adolescent transtibial and transfemoral amputees after the earthquake.

STUDY DESIGN

A prospective and descriptive study.

METHODS

A total of 21 adolescent unilateral amputees (11 transtibial and 10 transfemoral amputees) were recruited. Step Activity Monitors and Prosthesis Evaluation Questionnaire were used to assess patients over a 3-month period.

RESULTS

The average number of steps per day was 4577 ± 849 and 2551 ± 693 in transtibial and transfemoral amputees, respectively. Transtibial amputees had significantly higher (p < 0.05) levels of step activity than transfemoral amputees in all Step Activity Monitors measures. Prosthetic compliance was good with daily wearing time of above 12 h/day in both groups. Prosthesis Evaluation Questionnaire scores showed no significant difference between two groups.

CONCLUSIONS

The subjective quality of life is similar for adolescent amputees across transtibial and transfemoral amputation levels. Higher levels of step activity of transtibial amputees suggest that they have had lower energy expenditure and more capacity for ambulation.

CLINICAL RELEVANCE

This article involves a unique subset of young amputees who have sustained traumatic amputations following a major natural disaster. It provides a better understanding on the daily activities and quality of life, and could assist in optimizing the prosthetic outcomes of this subset of populations.

Longitudinal Relationship Among Physical Fitness, Walking-Related Physical Activity, and Fatigue in Children With Cerebral Palsy

BACKGROUND

A vicious circle of decreased physical fitness, early fatigue, and low physical activity levels (PAL) is thought to affect children with cerebral palsy (CP). However, the relationship of changes in physical fitness to changes in PAL and fatigue is unclear.

OBJECTIVE

The objective of this study was to investigate the associations among changes in physical fitness, walking-related PAL, and fatigue in children with CP.

DESIGN

This study was a secondary analysis of a randomized controlled trial with measurements at baseline, 6 months (after the intervention period), and 12 months.

METHODS

Twenty-four children with bilateral spastic CP and 22 with unilateral spastic CP, aged 7 to 13 years, all walking, participated in this study. Physical fitness was measured by aerobic capacity, anaerobic threshold, anaerobic capacity, and isometric and functional muscle strength. Walking-related PAL was measured using an ankle-worn activity monitor for 1 week. Fatigue was determined with the Pediatric Quality of Life (PedsQL) Multidimensional Fatigue Scale. Longitudinal associations were analyzed by random coefficient regression analysis.

RESULTS

In children with bilateral CP, all fitness parameters showed a positive, significant association with walking-related PAL, whereas no associations between physical fitness and walking-related PAL were seen in children with unilateral CP. No clinically relevant association between physical fitness and fatigue was found.

LIMITATIONS

Although random coefficient regression analysis can be used to investigate longitudinal associations between parameters, a causal relationship cannot be determined. The actual direction of the association between physical fitness and walking-related PAL, therefore, remains inconclusive.

CONCLUSIONS

Children with bilateral spastic CP might benefit from improved physical fitness to increase their PAL or vice versa, although this is not the case in children with unilateral CP. There appears to be no relationship between physical fitness and self-reported fatigue in children with CP. Interventions aimed at improving PAL may be differently targeted in children with either bilateral or unilateral CP.

Strong correlation between the 6-minute walk test and accelerometry functional outcomes in boys with Duchenne muscular dystrophy

Accelerometry provides information on habitual physical capability that may be of value in the assessment of function in Duchenne muscular dystrophy. This preliminary investigation describes the relationship between community ambulation measured by the StepWatch activity monitor and the current standard of functional assessment, the 6-minute walk test, in ambulatory boys with Duchenne muscular dystrophy (n = 16) and healthy controls (n = 13). All participants completed a 6-minute walk test and wore the StepWatch™ monitor for 5 consecutive days. Both the 6-minute walk test and StepWatch accelerometry identified a decreased capacity for ambulation in boys with Duchenne compared to healthy controls. There were strong, significant correlations between 6-minute walk distance and all StepWatch parameters in affected boys only (r = 0.701-0.804). These data proffer intriguing observations that warrant further exploration. Specifically, accelerometry outcomes may compliment the 6-minute walk test in assessment of therapeutic interventions for Duchenne muscular dystrophy.

The minimum number of days required to establish reliable physical activity estimates in children aged 2-15 years

The purpose of this study was to determine the minimum number of days needed to assess reliable estimates of step-count data for children based on age and gender. A total of 428 developing children (at least 30 boys and 30 girls in seven two-year intervals from 2-3 years to 14-15 years of age) wore a StepWatch accelerometer for 7 consecutive days. Following data screening, the 422 children's data were finally analyzed by age and sex groups using the Generalizability theory. Single-facet crossed designs (i.e. Participant (P) × Days (D)) were applied for each of 14 datasets. G-studies were performed to quantify the percentage of variance associated with the facet and interaction in the model. Follow-up D-studies were performed to determine the minimum number of days of step-count data collection needed to achieve a desirable reliability coefficient (G ≥ 0.80). The results from the G-studies show that P explained a large percentage of the total variance (26-71%) while D had little effect on the total variance (0-5%). A relatively large percentage of variance was unidentified (i.e. the P × D interaction). The minimum number of days necessary to achieve a desirable reliability coefficient (G ≥ 0.80) ranged from 2 to 12 d. On average, boys required less days of monitoring than girls. Researchers should use the findings of this study to design data collection that ensures reliable data.

Does a torsion adapter improve functional mobility, pain, and fatigue in patients with transtibial amputation?

BACKGROUND

Turning gait is an integral part of daily ambulation and likely poses a greater challenge for patients with transtibial amputation compared with walking a straight pathway. A torsion adapter is a prosthetic component that can increase transverse plane compliance of the prosthesis and decrease the torque applied to the residual limb, but whether this will improve patients' mobility, pain, and fatigue remains unknown.

QUESTIONS/PURPOSES

Does prescription of a torsion adapter translate to improvements in (1) functional mobility and (2) self-perceived pain and fatigue in moderately active patients with lower limb amputation?

METHODS

Ten unilateral transtibial amputees wore a torsion or rigid adapter in random order. Functional mobility was assessed through a field measurement using an activity monitor and through a laboratory measurement using a 6-minute walk test that included turns. The residual limb pain grade assessed self-perceived pain and the Multidimensional Fatigue Inventory assessed fatigue.

RESULTS

We found relatively small functional differences for amputees wearing a torsion adapter versus a rigid adapter. Amputees wearing a torsion adapter tended to take more low- and medium-intensity steps per day (331 ± 365 and 437 ± 511 difference in steps; effect size = 0.44 and 0.17; confidence interval [CI], 70-592 and 71-802; p = 0.019 and 0.024, respectively). They also experienced less pain interference with activities (1.9 ± 1.7 change in score; effect size = 0.83; CI, 0.3-3.4; p = 0.026) when wearing a torsion adapter. However, these patients took a similar number of total steps per day, walked a comparable distance in 6 minutes, and reported similar residual limb pain and fatigue.

CONCLUSIONS

For a moderately active group of amputees, the torsion adapter did not translate to substantial improvements in functional mobility and self-perceived pain and fatigue. The small increases in low- and medium-intensity activities with less pain interference when wearing a torsion adapter provides evidence to support prescribing this device for amputees with difficulty navigating the household and community environments.

Estimation of muscle strength from actigraph data in Duchenne muscular dystrophy

BACKGROUND

The purpose of this study was to evaluate the utility of a wrist actigraph for estimating muscle strength in Duchenne muscular dystrophy patients.

METHODS

Twenty-two patients aged 4-19 years wore a wrist actigraph to monitor activities of daily living, and underwent a test of knee extension strength and the 6 min walk test. These measures were made at baseline and at 1 year later. The actigraph data were quantified using the zero crossing mode (ZCM), which indicates the frequency of movement, and the proportional integration mode (PIM), which indicates activity level or vigor of motion.

RESULTS

The ZCM and PIM scores of ambulatory patients were higher than those of non-ambulatory patients (P < 0.001). The correlation coefficient between ZCM score and 6 min walk distance, ZCM score and knee extension strength, PIM score and 6 minute walk distance, and PIM score and knee extension strength was -0.44, 0.25, 0.58, and 0.63, respectively. This indicates that the PIM score had a moderate-good association with 6 min walk distance and knee extension strength.

CONCLUSION

Muscle strength can be estimated using the PIM score calculated from actigraph data. The PIM score is a good tool for the estimation of muscle strength.

The energy cost of playing active video games in children with obesity and children of a healthy weight

BACKGROUND

Increasing physical activity and reducing sedentary behaviour form a large part of the treatment of paediatric obesity. However, many children today spend prolonged periods of time playing sedentary video games. Active video games (AVGs) represent a novel and child friendly form of physical activity.

OBJECTIVES

To measure the energy cost of playing two AVGs in children with obesity and healthy age- and gender-matched children.

METHODS

The energy cost of gaming and heart rates achieved during gaming conditions were compared between groups.

RESULTS

AVG play can result in light-to-moderate intensity physical activity (2.7-5.4 metabolic equivalents). When corrected for fat-free mass those with obesity expended significantly less energy than healthy weight peers playing Nintendo Wii Fit Free Jogging (P = 0.017). No significant difference was seen between groups in the energy cost of playing Boxing.

CONCLUSION

Certain AVGs, particularly those that require lower limb movement, could be used to increase total energy expenditure, replace more sedentary activities, or achieve moderate intensity physical activity among children with obesity. There seems to be some differences in how children with obesity and children of a healthy weight play AVGs. This could result in those with obesity expending less energy than their lean peers during AVG play.

Effect of bilateral step-up and -down training on motor function in a person with hemiparesis: a case report

Gait training to facilitate the use of the paretic limb for persons with hemiparesis continues to be of interest to those in the clinical research domain. The purpose of this case report was to assess the outcomes of a repeated step-up and -down treatment, initiating with the paretic limb, on functional mobility, endurance and gait kinematic parameters in a person with hemiparesis. The participant was an 85-year-old female 3 years status post left hemiparesis, who reported overall good health. The participant was asked to step up on a 1-inch height wood box with her paretic limb. Once both feet were on top of the box, the participant initiated descent also with her paretic limb. The height of the box gradually progressed to 5 inches based on the participant's performance and tolerance. A metronome was used to facilitate rhythmic lower extremity movement patterns. The training duration for each treatment session was 7-15 min/day. The participant completed nine sessions spanning over 3 weeks. The outcome measure used to identify motor recovery was the Fugl-Myer (lower extremity). In addition, the timed up and go (TUG), the 6-min walk test (6 MWT) and gait kinematics were assessed to examine mobility and gait. The Fugl-Myer score and 6 MWT did not reflect a meaningful change (0% and +2.6%, respectively). However, TUG scores did show a meaningful change (+31.9%). With respect to gait kinematics, hip flexion on the paretic limb was improved from 11° to 18°, which indicates the normal range of hip motion during the initial swing phase in post-test.

Walking activity of children with cerebral palsy and children developing typically: a comparison between the Netherlands and the United States

PURPOSE

To compare walking activity of children with and without cerebral palsy (CP) between the Netherlands and the United States.

METHODS

A cross-sectional analysis on walking activity data from an international retrospective comparison study including a convenience sample of 134 walking children aged 7-12 years with spastic CP, classified as Gross Motor Function Classification System (GMFCS) level I (N = 64), II (N = 49) or III (N = 21), and 223 typically developing children (TDC) from the Netherlands and the United States. Walking activity was assessed during a one-week period using a StepWatch™ activity monitor. Outcomes were the daily number of strides, daily time being inactive and spent at low (0-15 strides/min), moderate (16-30 strides/min) and high stride rate (31-60 strides/min). Walking activity was compared between countries using multiple linear regression analyses.

RESULTS

Walking activity of TDC was not significantly different between countries. Compared to their American counterparts, Dutch children in GMFCS level I and II showed less walking activity (p < 0.05), whereas Dutch children in GMFCS level III showed more walking activity (p < 0.05).

CONCLUSION

The absence of differences in walking activity between Dutch and American TDC, and the presence of differences in walking activity between Dutch and American children with CP suggest that between-country differences affect walking activity differently in children with CP.

IMPLICATIONS FOR REHABILITATION

Physical activity of children with CP should be promoted in both the United States and the Netherlands. The between-country differences in walking activity illustrate that apart from the severity of the CP walking activity seems to be influenced by environmental aspects. In the promotion of physical activity, practitioners should pay attention to environmental barriers that families may experience for increasing physical activity.

Active video games as an exercise tool for children with cystic fibrosis

BACKGROUND

Active video games are used in many hospitals as exercise tools for children with cystic fibrosis. However, the exercise intensity associated with playing these games has not been examined in this population.

METHODS

Children with cystic fibrosis [n=30, aged 12.3 (2.6) years, 17 boys, BMI 17.7 (2.8) kg/m(2)] were recruited from outpatient clinics in Dublin hospitals. Age and gender matched control children were recruited from local schools. Oxygen consumption, metabolic equivalents (METs) calculated from resting V˙O2, and heart rate were measured while playing Nintendo Wii™ (Nintendo Co. Ltd., Tokyo, Japan) Sports Boxing and Nintendo Wii Fit Free Jogging using a portable indirect calorimeter (Oxycon Mobile).

RESULTS

Playing Wii Boxing resulted in light intensity activity (2.46METs) while playing Wii Fit Free Jogging resulted in moderate intensity physical activity (4.44METs). No significant difference was seen between groups in the energy cost of playing active video games.

CONCLUSION

Active video games are a useful source of light to moderate intensity physical activity in children with cystic fibrosis.

Effect of BMI on pedometers in early adolescents under free-living conditions

PURPOSE

Pedometers may provide valuable information regarding the ambulatory patterns of adolescents, but the effects of body mass index (BMI) on pedometer accuracy in this population are unknown.The purpose of this study was twofold: 1) to determine whether the New Lifestyles NL-2000 (NL) and the Digi-Walker SW-200 (DW) (New Lifestyles, Inc., Lees Summit, MO) yield similar step counts as compared with an ankle-mounted criterion, StepWatch 3, when worn by early adolescents in a free-living environment and 2) to study whether BMI percentile affects the accuracy of waist-mounted pedometers in adolescents.

METHODS

Seventy-four early adolescents (13.0 ± 1.1 yr) wore the devices during one weekday. The study population included 33 normal weight, 21 overweight, and 20 obese participants. Two-way repeated-measures ANOVA was used to determine whether the BMI and the device were related to the number of steps per day and percentage of actual steps.

RESULTS

The NL and DW recorded fewer steps than the StepWatch 3 in each BMI category (P < 0.05). In the obese group, the DW underestimated the steps more than the NL (P < 0.001). For the normal weight, overweight, and obese groups, the NL counted 89.1%, 89.1%, and 91.6% of the steps, respectively, whereas the DW counted 86.7%, 84.6%, and 72.7%, respectively.

CONCLUSION

Researchers must be cognizant of the limitations of waist-mounted pedometers and carefully choose a device that suits the needs of their investigations. Because of the inaccuracies of the DW when measuring steps in obese adolescents, careful consideration must be given before choosing this device for research and interventions. The NL is a better device for assessment of adolescents' steps than the DW, especially for those who are obese.

The effect of individualized exercise interventions during treatment in pediatric patients with a malignant bone tumor

BACKGROUND

While research on exercise interventions during anticancer treatment is well-established in adults, only very few studies exist in children. However, pediatric patients experience great limitations to being physically active, and appropriate interventions are desired.

PROCEDURE

The present study aimed at investigating the effects of individualized exercise interventions during inpatient stays on pediatric patients with a malignant bone tumor. The parameter of interest was physical activity (PA). Patients' PA during home stays was assessed 6 weeks as well as 3, 6, 12, and 18 months post-surgery. Patients were distinguished into an intervention group and a control group. All patients received endoprosthetic replacement of the affected bone in the same institution.

RESULTS

A constant increase in all PA parameters was observed during follow-up. Exercise interventions were possible and appeared worthwhile. The intervention group showed better PA results at all measurements; however, no significant differences between groups were found. Furthermore, differences decreased especially after the cessation of the intervention. General problems in reaching appropriate power and compliance were observed.

CONCLUSIONS

Individualized exercise interventions in pediatric bone tumor patients are possible and appear to be beneficial. Such interventions should be implemented in adjuvant care; however, future research is needed to understand more about the effects of different interventions.

Motor proficiency, strength, endurance, and physical activity among middle school children who are healthy, overweight, and obese

PURPOSE

To compare motor proficiency, strength, endurance, and physical activity among children from minority backgrounds who were healthy weight (HW), overweight (OW), or obese (OB).

METHODS

Eighty-six children, aged 10 to 15 years, of mostly Hispanic ethnicity, participated. Children were categorized according to body mass index-for-age percentile. Bruininks-Oseretsky Test of Motor Proficiency (BOT2) Short Form, Sit-to-Stand (STS), Timed Up and Down Stairs, and 6-Minute Walk Test (6MWT) were administered. Physical activity was measured by using activity monitors.

RESULTS

Forty-five percent of children were classified as OW/OB. Children who were OB had lower mean BOT2, STS, and 6MWT performance than children of HW. Among children who were OW/OB, daily mean steps were lower and sedentary minutes higher than children of HW. In children who were OW/OB, body mass index was negatively correlated with BOT2, STS, and abdominal curls.

CONCLUSION

Children who are OB demonstrate greater impairments in motor proficiency, strength, and endurance and participate in less physical activity than peers of HW.

Metabolic syndrome and daily ambulation in children, adolescents, and young adults

PURPOSES

To compare daily ambulatory measures in children, adolescents, and young adults with and without metabolic syndrome and to assess which metabolic syndrome components, demographic measures, and body composition measures are associated with daily ambulatory measures.

METHODS

Two-hundred fifty subjects between the ages of 10 and 30 yr were assessed on metabolic syndrome components, demographic and clinical measures, body fat percentage, and daily ambulatory strides, durations, and cadences during seven consecutive days. Of the 250 subjects, 45 had metabolic syndrome, as defined by the International Diabetes Federation.

RESULTS

Subjects with metabolic syndrome ambulated at a slower daily average cadence than those without metabolic syndrome (13.6 ± 2.2 vs 14.9 ± 3.2 strides per minute; P = 0.012), and they had slower cadences for continuous durations of 60 min (P = 0.006), 30 min (P = 0.005), 20 min (P = 0.003), 5 min (P = 0.002), and 1 min (P = 0.001). However, the total amount of time spent ambulating each day was not different (P = 0.077). After adjustment for metabolic syndrome status, average cadence is linearly associated with body fat percentage (P < 0.001) and fat mass (P < 0.01). Group difference in average cadence was no longer significant after adjusting for body fat percentage (P = 0.683) and fat mass (P = 0.973).

CONCLUSIONS

Children, adolescents, and young adults with metabolic syndrome ambulate more slowly and take fewer strides throughout the day than those without metabolic syndrome, although the total amount of time spent ambulating is not different. Furthermore, the detrimental influence of metabolic syndrome on ambulatory cadence is primarily a function of body fatness.

Reliably measuring ambulatory activity levels of children and adolescents with cerebral palsy

OBJECTIVE

To identify sources of variance in step counts and to examine the minimum number of days required to obtain a stable measure of habitual ambulatory activity in the cerebral palsy (CP) population.

DESIGN

Cross-sectional.

SETTING

Free-living environments.

PARTICIPANTS

Children and adolescents with CP (N=209; mean age ± SD, 8y, 4mo ± 3y, 4mo; n=118 boys; Gross Motor Function Classification System [GMFCS] levels I-III) were recruited through 3 regional pediatric specialty care hospitals.

INTERVENTIONS

Daily walking activity was measured with a 2-dimensional accelerometer over 7 consecutive days. An individual information-centered approach was applied to days with <100 steps, and participants with ≥3 days of missing values were excluded from the study. Participants were categorized into 6 groups according to age and functional level. Generalizability theory was used to analyze the data.

MAIN OUTCOME MEASURES

Mean step counts, relative magnitude of variance components in total step activity, and generalizability coefficients (G coefficients) of various combinations of days of the week.

RESULTS

Variance in step counts attributable to participants ranged from 33.6% to 65.4%. For youth ages 2 to 5 years, a minimum of 8, 6, and 2 days were required to reach acceptable G coefficient (reliability) of ≥.80 for GMFCS levels I, II, and III, respectively. For those ages 6 to 14 years, a minimum of 6, 5, and 4 days were required to reach stable measures of step activity for GMFCS levels I, II, and III, respectively.

CONCLUSIONS

The findings of the study suggest that an activity-monitoring period should be determined based on the GMFCS levels to reliably measure ambulatory activity levels in youth with CP.

A systematic review of the clinimetric properties of habitual physical activity measures in young children with a motor disability

Aim. To identify and systematically review the clinimetric properties of habitual physical activity (HPA) measures in young children with a motor disability. Method. Five databases were searched for measures of HPA including: children aged <6.0 years with a neuromuscular disorder, physical activity defined as "bodily movement produced by skeletal muscles causing caloric expenditure", reported HPA as duration, frequency, intensity, mode or energy expenditure, and evaluated clinimetric properties. The quality of papers was assessed using the COSMIN-checklist. A targeted search of identified measures found additional studies of typically developing young children (TDC). Results. Seven papers assessing four activity monitors met inclusion criteria. Four studies were of good methodological quality. The Minimod had good ability to measure continuous walking but the demonstrated poor ability to measure steps during free-living activities. The Intelligent Device for Energy Expenditure and Activity and Ambulatory Monitoring Pod showed poor ability to measure activity during both continuous walking and free-living activities. The StepWatch showed good ability to measure steps during continuous walking in TDC. Interpretation. Studies assessing the clinimetric properties of measures of HPA in this population are urgently needed to allow assessment of the relationship between HPA and health outcomes in this group.

[Objective measurement tools for the assessment of physical activity]

The aim of the present study was to provide an overview about the various measurement options for the quantitative assessment of physical activity in daily life. After briefly discussing the importance of physical activity in this era of civilization-related health problems characterized by increasing malnutrition problems in combination with increasing lack of movement in daily life, the different types of measurement systems available and their applicability are described. It is hoped that this information will assist the potential user or buyer of a new measurement system to make a well-informed decision about the appropriate tool for a specific research interest.

Functional limitations associated with end-stage ankle arthritis

BACKGROUND

Ankle arthritis, like hip and knee arthritis, has a substantial impact on patient function. Understanding the functional limitations of ankle arthritis may help to stratify treatment strategies.

METHODS

We measured the preoperative demographic characteristics, physical function, and self-assessed function of patients with end-stage ankle arthritis and identified correlations among these metrics. Participants wore a StepWatch 3 Activity Monitor for two weeks and completed the Musculoskeletal Function Assessment and Short Form-36 surveys. Gait kinematics and kinetics were also measured as participants walked at a self-selected pace.

RESULTS

Musculoskeletal Function Assessment and Short Form-36 scores revealed reduced perceived function for patients with end-stage ankle arthritis compared with healthy controls. These patients also took fewer total steps per day, took fewer high-intensity steps, and chose to walk at a slower walking speed. Gait analysis revealed reduced ankle motion, peak ankle plantar flexor moment, peak ankle power absorbed, and peak ankle power generated for the affected limb compared with the unaffected limb. High-intensity step count was also correlated with both survey scores, walking speed, step length, peak ankle plantar flexor moment, and peak ankle power generated. Walking speed, step length, and ankle motion were correlated with peak ankle plantar flexor moment and power generated.

CONCLUSIONS

Generally, patients with end-stage ankle arthritis have reduced physical and perceived function compared with healthy individuals. Additionally, high-intensity step count was a better indicator of physical and perceived function compared with total steps per day for this population.

Ambulatory activity of children with cerebral palsy: which characteristics are important?

AIM

To assess ambulatory activity of children with cerebral palsy (CP), aged 7 to 13 years, and identify associated characteristics.

METHOD

  Sixty-two children with spastic CP (39 males, 23 females; mean age 10y 1mo, SD 1y 8mo; age range 7-13y), classified as Gross Motor Function Classification System (GMFCS) levels I to III, participated. Ambulatory activity was measured during 1 week with a StepWatch activity monitor as steps per day, and time spent at medium and high step rates. Multiple linear regression analyses were performed following a backward selection procedure until only independent variables with p<0.05 remained in the model. Ambulatory activity outcome parameters served as dependent variables, and disease, personal, and environmental characteristics as independent variables. Ambulatory activity was corrected for body height.

RESULTS

Children took more steps during school days (5169 steps, SD 1641) than during weekend days (4158 steps, SD 2048; p<0.001). Higher GMFCS level, bilateral CP, and higher age were associated with lower ambulatory activity on school days (R(2) ranged from 43-53%), whereas bilateral CP, higher age, and no sport club participation were associated with lower ambulatory activity in the weekend (R(2) ranged from 21-42%). Correcting for body height decreased the association with age.

INTERPRETATION

Interventions should focus at increasing physical activity at the weekend for children with bilateral spastic CP.

Objective assessment of brace wear times and physical activities in two patients with scoliosis

Conservative treatment of adolescent idiopathic scoliosis consists of therapeutic exercise and the application of braces. The effectiveness of bracing mainly depends on patient compliance, which can be determined by means of temperature sensors. This methodological paper describes the feasibility of objectively determining compliance and daily physical activities before and during conservative scoliosis treatment, being a relevant indicator for quality of life in children and adolescents. One patient with low compliance (61.4±24.9%) reduced her activity level during bracing by 50.1%, whereas another patient with a satisfactory compliance (85.7±19.5%) increased her daily activity level by 33.7% during conservative treatment.

Concurrent validation of a magnetometer-based step counter in various walking surfaces

BACKGROUND AND AIM

Clinicians need a simple method for quantifying gait activity. The aim of this study was to develop and validate the reliability of a quantitative gait assessment based exclusively on one magnetometer located on the shank.

METHODS

Twenty-five healthy volunteers were simultaneously equipped with a magnetometer (MAG system) on the right shank, and two validated step-counter systems: the StepWatch Activity Monitor (SAM) and three Force-Sensing Resistors (FSRs). Volunteers performed a standard circuit including level walking, up and down stairs and up and down a slope. The three step counting approaches were compared using the Pearson correlation coefficient and the Bland-Altman method for each of the surface-types.

RESULTS

The step counts measured by the MAG and FSR were highly correlated for all the surfaces (r>.83). Congruently, the Bland-Altman analysis revealed an overall ± 5% limit of agreement. The step counts measured by the MAG and SAM were also well correlated for the level-surface condition (r=.85), with a Bland-Altman ± 5% limit of agreement but comparisons were less satisfying for the other surfaces.

CONCLUSIONS

These results demonstrate that the use of a single magnetometer is an accurate tool for step counting over varied surfaces. These small sensors are easy to set up and to use and the signal processing is robust, making the MAG method highly applicable for clinical purposes, especially for the analysis of long walking periods in daily life conditions.

Stride activity level in young and middle-aged adults with hip disorders

OBJECTIVES

To determine the activity level, represented by total daily strides (TDS), of young and middle-aged adults with hip disorders and asymptomatic controls and to assess the association between TDS and self-report functional measures.

METHODS

Patients (age 15-50) with deep hip or groin pain (n=202) and controls (n=20) wore an accelerometer that recorded TDS. Symptomatic subjects completed self-report questionnaires. Symptomatic subjects were classified into subgroups: femoroacetabular impingement (FAI), developmental dysplasia of the hip (DDH), isolated labral tear (LT) and osteoarthritis (OA) based on intraoperative findings. Between-group comparisons of TDS were performed and correlations between TDS and questionnaires were determined.

RESULTS

Overall, controls recorded greater TDS than symptomatic subjects; however, between-group comparisons showed that FAI and DDH were similar to controls. OA demonstrated fewer TDS than FAI (4327 [2075] vs. 5095 [2354]). In symptomatic subjects, TDS had a low correlation with modified Harris Hip Score (r=0.33) and the University of California Los Angeles Activity Score (ρ=0.30), but no correlation with the Marx Activity Rating Scale.

CONCLUSIONS

Subjects with hip disorders demonstrate reduced TDS compared with controls; however, some subgroups demonstrated TDS similar to controls. In addition, symptomatic subjects demonstrated relatively high TDS while reporting poor function. Accelerometers can be used in clinical populations to provide additional information about activity not represented by traditional functional measures.

Arterial elasticity in American Indian and Caucasian children, adolescents, and young adults

We compared arterial elasticity in American Indian and Caucasian children, adolescents, and young adults, and we assessed whether demographic, body composition, and ambulatory activity measures were predictive of arterial elasticity within each group. Fifty-one American Indians and 66 Caucasians between the ages of 8 and 30 years were assessed on large artery elasticity index, small artery elasticity index, body fat percentage, and daily ambulatory activity during 7 consecutive days. American Indians had a higher percentage of body fat than Caucasians (p = 0.002), whereas daily ambulatory activity measures were similar (p > 0.05). American Indians had a 16% lower large artery elasticity index (p = 0.007) and a 19% lower small artery elasticity index (p < 0.001) than Caucasians. The regression model for large artery elasticity index included average cadence (p = 0.001), fat-free mass (p < 0.001), age component (Caucasian only) (p < 0.001), and sex (p = 0.025). The regression model for small artery elasticity index included fat-free mass (p < 0.001), maximum cadence for 30 continuous minutes (p = 0.009), race (p = 0.005), and average cadence (p = 0.049). Between 8 and 30 years of age, elasticity means for the large and small arteries is lower in American Indians than in Caucasians. A smaller difference was observed in children, with a trend to a much larger difference in young adults. Furthermore, greater fat-free mass and higher daily ambulatory cadence are associated with higher arterial elasticity in both American Indians and Caucasians.

Vacuum-assisted socket suspension compared with pin suspension for lower extremity amputees: effect on fit, activity, and limb volume

OBJECTIVE

To investigate the effect of a vacuum-assisted socket suspension system as compared with pin suspension on lower extremity amputees.

DESIGN

Randomized crossover with 3-week acclimation.

SETTING

Household, community, and laboratory environments.

PARTICIPANTS

Unilateral, transtibial amputees (N=20 enrolled, N=5 completed).

INTERVENTIONS

(1) Total surface-bearing socket with a vacuum-assisted suspension system (VASS), and (2) modified patellar tendon-bearing socket with a pin lock suspension system.

MAIN OUTCOME MEASURES

Activity level, residual limb volume before and after a 30-minute treadmill walk, residual limb pistoning, and Prosthesis Evaluation Questionnaire.

RESULTS

Activity levels were significantly lower while wearing the vacuum-assisted socket suspension system than the pin suspension (P=.0056; 38,000 ± 9,000 steps per 2 wk vs 73,000 ± 18,000 steps per 2 wk, respectively). Residual limb pistoning was significantly less while wearing the vacuum-assisted socket suspension system than the pin suspension (P=.0021; 1 ± 3mm vs 6 ± 4mm, respectively). Treadmill walking had no effect on residual limb volume. In general, participants ranked their residual limb health higher, were less frustrated, and claimed it was easier to ambulate while wearing a pin suspension compared with the VASS.

CONCLUSIONS

The VASS resulted in a better fitting socket as measured by limb movement relative to the prosthetic socket (pistoning), although the clinical relevance of the small but statistically significant difference is difficult to discern. Treadmill walking had no effect, suggesting that a skilled prosthetist can control for daily limb volume fluctuations by using conventional, nonvacuum systems. Participants took approximately half as many steps while wearing the VASS which, when coupled with their subjective responses, suggests a preference for the pin suspension system.

Are diurnal changes in foot sole sensation dependent on gait activity?

The foot sole is loaded during stance and gait and plantar cutaneous mechanoreceptors sense the local stress distribution. It is not clear whether the perception thresholds of these mechanoreceptors change during the day and how they respond to walking activities. The primary aim of the present study was to investigate diurnal changes of plantar sensitivity. Furthermore, the aim was to find out whether daily changes depend on the individual level of step activity. Twenty-six healthy subjects, 17 women and 9 men, aged 28.6±6.7 years participated in the study. Detection thresholds to light touch were measured in six plantar regions with Semmes-Weinstein monofilaments in the morning, noon and afternoon. Step activity was recorded with a StepWatch™ Activity Monitor and analyzed for three periods (8 a.m.-4 p.m., 8 a.m.-12 p.m., 12 p.m.-4 p.m.). The hallux, the 3rd metatarsal head and the heel showed significantly decreased detection thresholds from 8 a.m. to 4 p.m. (p≤0.05). A fair correlation between the decrease of detection threshold and the total number of steps was found for the 3rd metatarsal head and the heel (p≤0.05). Foot sole sensation appears to improve during the day and seems to be associated with the step activity. This may reflect an improving transfer of afferent information to the central nervous system during the day as well as an adaptation of receptors to gait activity.

Prospective evaluation of physical activity in patients with idiopathic scoliosis or kyphosis receiving brace treatment

Bracing is an established method of conservative treatment for adolescent idiopathic scoliosis and kyphosis. Compliance among adolescents is frequently inadequate due to the discomfort of wearing a brace, cosmetic issues, and fear on the part of patients and parents that bracing may reduce everyday physical activities. The aim of this prospective, controlled study was to objectify the impact of spinal bracing on daily step activity in patients receiving conservative treatment for adolescent idiopathic scoliosis (AIS) or adolescent kyphosis (AK). Forty-eight consecutive patients (mean age 13.4 ± 2.3 years), consisting of 38 AIS patients (33 girls, 5 boys) and 10 AK patients (6 girls, 4 boys) were included. Once the decision to carry out bracing had been taken and while the patients were waiting for the individual brace to be built, step activity was assessed without braces by means of step activity monitoring (SAM) for seven consecutive days. After 8 weeks of brace wearing, step activity was assessed during regular brace treatment, again for seven consecutive days. In addition, brace-wearing times were simultaneously recorded using temperature probes implanted in the braces to measure compliance. Before and during brace treatment, patients completed the Scoliosis Research Society (SRS-22) questionnaire. The SAM was worn for an average of 12.7 ± 1.5 h/day during the first measurement and 12.3 ± 1.9 h on average during the second measurement. The mean gait cycles (GCs) per day and per hour before treatment were 5,036 ± 1,465 and 395 ± 105, respectively. No significant reduction in step activity was found at the follow-up measurement during bracing, at 4,880 ± 1,529 GCs/day and 403 ± 144 GCs/h. Taking the 23-h recommended time for brace wearing as a basis (100%), patients wore the brace for 72.7 ± 27.6% of the prescribed time, indicating an acceptable level of compliance. Girls showed a higher compliance level (75.6 ± 25.6%) in comparison with boys (56.7 ± 31.9%), although the difference was not significant (P = 0.093). The SRS-22 total score showed no differences between the two measurements (2.57 ± 0.23 vs. 2.56 ± 0.28). Implementing a simultaneous and objective method of assessing step activity and brace-wearing times in everyday life proved to be feasible, and it expands the information available regarding the impact of bracing on patients' quality of life. The results clearly show that brace treatment does not negatively interfere with daily step activity in AIS and AK patients. This is an important finding that should help reduce patients' and parents' worries concerning bracing.