Lengthening sleep reduces pain in childhood arthritis: a crossover randomised controlled trial.

OBJECTIVES: Juvenile idiopathic arthritis (JIA) is a common chronic childhood disease and chronic pain is a debilitating feature. A strong link has been shown between poor sleep and pain in JIA. However, the causal direction is unknown. This study's aim was to determine if, in adolescents with JIA, a recommended healthful sleep duration leads to reductions in pain when compared with the restricted sleep (RS) duration that is commonly seen. METHODS: Patients with JIA (12-18 years old; pain score of ≥1 on a visual analogue scale) participated in a randomised, crossover sleep manipulation protocol. The 3-week protocol comprised a baseline week (BL), a week with healthy sleep duration (HSD; 9.5 hours in bed/night) and a RS week (RS; 6.5 hours in bed/night). After BL, participants were randomly assigned to either HSD or RS, and then crossed over to the other condition. Pain was self-assessed using the iCanCope with Pain app. We used Bayesian hierarchical models to estimate the effect of sleep duration on pain. RESULTS: Participants (n=31; mean age=15.0±1.8 years) averaged 1.4 (95% credible interval (CrI) 1.2-1.6) more hours of sleep per night during HSD relative to RS. Compared with RS, HSD resulted in a favourable effect on pain scores (OR 0.61, 95% CrI 0.39-0.95). CONCLUSION: It is possible to have adolescents with childhood arthritis get a healthier sleep duration, and this longer sleep results in reduced pain. These findings complement prior correlational studies and confirm a causal relationship between reduced sleep duration and increased pain. TRIAL REGISTRATION NUMBER: NCT04133662.

Social network size and mental health outcomes in youth with neuroinflammatory disorders.

BACKGROUND: 75 % of youth with MS report symptoms of fatigue, depression, and anxiety. Social network size (number of people in an individual's network) is known to have positive impacts on health and health behavior in pediatric populations and in individuals with multiple sclerosis. OBJECTIVES: To estimate associations between social network size (SNS) and depression, anxiety, symptoms of post-traumatic stress disorder (PTSD), and quality of life among youth with recurrent neuroinflammatory disorders (RNI) in comparison to that of youth with monophasic acquired demyelinating syndrome (mono-ADS). METHODS: Youth with RNI and mono-ADS were recruited from the Pediatric Neuroinflammatory Disorders Clinic at the Hospital for Sick Children between September 2020 and August 2022. After consent, participants completed the questionnaires on social network composition, depression, anxiety, PTSD, and quality of life. Descriptive and inferential analyses were conducted for differences between cohorts and correlations. RESULTS: Youth with RNI (n = 37, Female= 22, Median age= 15, IQR= 3) and mono-ADS (n = 23, Female= 12, Median age= 14, IQR= 4.5) did not differ in: SNS, depression, anxiety, PTSD, and quality of life. Larger SNS was associated with lower anxiety (rs= -0.350, p<0.05) in youth with RNI and youth with RNI who presented anxiety disorder had significantly lower number of social contacts than those who did not (t = 2.23, p = 0.033, ES= 0.90) but not in mono-ADS. When analyzing the two cohorts grouped together, all youth who screened for anxiety had significantly smaller network size than those who did not (t = 2.06, p = 0.045, ES= 0.66). This was similar with those who screened for depression (t = 2.05, p = 0.046, ES= 0.58). CONCLUSIONS: In youth with RNI, SNS was associated with anxiety. SNS is one important aspect of social networks that have the potential to shape mental health in youth with neuroinflammatory disorders. Future studies should focus on social network composition, strength of ties, and types of support in shaping health outcomes.

Male reproductive success is not strongly affected by phenological changes in mate availability in monoecious Sagittaria latifolia.

Many plants express their female and male sex roles at different times (dichogamy), with important consequences for mating. Dichogamy can yield mate limitation via biased floral sex ratios, particularly at the beginning and end of the flowering season when many plants simultaneously function as the same sex. This form of mate limitation should be reduced if plants adjust their allocations to female versus male sex functions in a manner that tracks seasonal variability in mating opportunities. For example, under protogyny (i.e. dichogamy with female function expressed first) plants with male-biased sex expression should have enhanced mating opportunities early in the flowering season as other plants begin to flower (in female sex phase). We quantified seasonal changes in sex allocation, patterns of mate availability and realized siring success in a population of protogynous Sagittaria latifolia. Our results were consistent with previous findings that seasonal changes in sex allocation should compensate for lost mating opportunities under the temporally variable mating environments caused by dichogamy. However, patterns of siring success in the population were inconsistent with this interpretation. We suggest that realized siring success might depend more strongly on spatial than on temporal aspects of mate availability.

Unraveling the pathophysiology of lower-limb postthrombotic syndrome in adolescents: a proof-of-concept study.

A better understanding of the pathophysiology of pediatric postthrombotic syndrome (PTS) is needed to develop strategies to treat this condition. We investigated calf pump function, exercise capacity, balance in power output, and changes in limb muscle oxygen saturation (SmO2) and fluid content during exercise in 10 pediatric patients with unilateral lower-limb PTS, and in age- and sex-matched controls (1:1-1:2 ratio). Outcomes were investigated using bioimpedance spectroscopy, torque-sensing pedals, and near-infrared spectroscopy during incremental- and constant-load cycling tests. The median age at participation was 17 years (25th-75th percentile, 15-18 years); 68% of participants were females. The median CAPTSure score in the affected leg of affected participants was 35 points (25th-75th percentile, 24-46 points), indicating moderate/severe PTS; 20% of patients had a history of central venous catheter-related thrombosis. Increasing PTS severity was associated with higher calf pump venous volume and higher ejection volume, leading to compensated calf pump performance. We found no evidence of PTS impact on exercise capacity. Leg contribution to power output was similar in affected and unaffected legs. However, the PTS-affected legs showed lower SmO2 during active cycling and recovery with increasing PTS severity, indicating impaired microvascular function in the muscle. These findings suggest that PTS severity is associated with impaired blood flow, presumably from elevated venous pressure during and after exercise. The fact that microvascular function is impaired in young patients with PTS underscores the relevance of developing strategies to mitigate the effects of this chronic vascular disease to minimize its deleterious effects as children grow older.

Functional impact of pediatric postthrombotic syndrome.

BACKGROUND: Postthrombotic syndrome (PTS) is the most common complication of deep vein thrombosis (DVT) in children. OBJECTIVES: We aimed to assess the impact of pediatric PTS on functioning as assessed by movement ability, mobility, functional disability, and physical activity levels in children after diagnosis of limb DVT. METHODS: Patients aged 8-21 years in follow-up care after objectively documented limb DVT were prospectively recruited in this cross-sectional study. Measures of functioning (outcomes) included self-reported questionnaires that assessed: 1) movement ability, measured with the Movement Ability Measure-Computer Adaptive Test version; 2) mobility, evaluated with the Computer Adaptive Test version of the Patient-Reported Outcomes Measurement Information System Pediatric Physical Functioning, Mobility domain; 3) functional disability, evaluated with the Functional Disability Inventory; and 4) physical activity levels, evaluated with the Godin Leisure-Time Exercise Questionnaire. The main predictor was PTS severity, which was assessed using the index for the Clinical Assessment of PTS in children. The association between PTS and outcomes was analyzed using linear models. RESULTS: Eighty-seven patients (median age, 16 years; 25th-75th percentile, 15-18 years; 56% boys) were enrolled. Adjusted for age, sex, and underlying condition, increasing PTS severity was associated with lower current movement ability, a wider gap between current vs preferred movement ability, lower mobility, and slightly higher functional disability scores. There was a nonsignificant effect of PTS severity on moderate-strenuous physical activity. CONCLUSION: In children, increased PTS severity is associated with lower movement ability and impaired mobility. Reducing the gap between the patients' current vs preferred movement ability is a relevant aspect of PTS management in children.

Feasibility of the wingate anaerobic exercise test as a clinical measure in patients with juvenile dermatomyositis.

BACKGROUND: Core sets, while widely adopted for clinical assessment in juvenile dermatomyositis (JDM), have some drawbacks - they are time consuming, were developed primarily for research, and require an experienced multidisciplinary team. We propose the Wingate Anaerobic Test, a 30-s all out test performed on a cycle ergometer, as a potential alternative; it is valid and reliable in this patient population. We aimed to determine the feasibility of performing the Wingate test as part of a typical clinic visit, and to determine if it is correlated to current measures of disease activity. METHODS: Patients 5-18 years of age, with JDM, were recruited from the JDM clinic at a large Canadian academic children's hospital. Participants underwent a standard clinic assessment, then completed a Wingate test at the end of the visit. RESULTS: Twenty-six patients participated in the study, representing a recruitment rate of 81%; of those, 88% were able to complete the Wingate test. Patients liked the Wingate test and felt it should be included as a regular clinic test. Absolute peak power (watts) on the Wingate test was strongly correlated to the manual muscle test (MMT-8) and the timed squat test. Relative peak power (watts/kg) on the Wingate test was strongly correlated to the timed squat test and the Childhood Myositis Assessment Scale (CMAS). Exploratory principal components analysis revealed that Wingate relative average power explained almost 2/3 of the variance of the CMAS, MMT and timed squats combined. CONCLUSION: The Wingate test is a feasible test for children with JDM and correlates well with standard clinical assessments. Given its brevity, it has the potential to replace more standard measures of physical function currently used in clinical assessments for children with JDM. Future work should focus on how best to operationalize Wingate testing in clinic without the use of dedicated personnel.

Physical Activity and Sedentary Behavior Patterns Across Weekdays and Weekend Days in Youth With Multiple Sclerosis and Controls.

Background: This study quantified and compared weekday and weekend patterns of device-measured physical activity (PA) and sedentary behavior between youth with pediatric multiple sclerosis (MS) and controls for the purpose of informing future PA behavior change interventions. Methods: Participant data were obtained from 3 ongoing observational studies, and the sample included 40 participants with pediatric MS and 41 controls. Light PA (LPA), moderate to vigorous PA (MVPA), and sedentary behavior data were collected using activity monitors (ActiGraph LLC) over 1 week. The main analysis involved a 2-way mixed factor analysis of variance with group as a between-subjects factor (pediatric MS vs control) and day as a within-subjects factor (weekday vs weekend day). Results: There was no group by day interaction from the analysis of variance for percentage of activity monitor wear time spent in LPA, MVPA, or sedentary behavior. There was no effect of group for LPA, MVPA, or sedentary behavior. There was an effect of day of week on percentage of day spent in LPA, MVPA, and sedentary behavior. Conclusions: These results suggest that youth with pediatric MS and controls were less physically active and more sedentary on weekends than on weekdays, but there were no differences between groups in PA and sedentary behavior overall or by day of the week. Physical activity interventions may be more successful by initially targeting weekend day activity.

Pandemic-associated mental health changes in youth with neuroinflammatory disorders.

BACKGROUND: Children with neuroinflammatory disorders have high rates of anxiety and depression, alongside low rates of physical activity. Given general concerns for mental and physical health in children during the COVID-19 pandemic lockdown, here we sought to understand how sleep, anxiety, depression, and physical activity changed with the lockdown in children with neuroinflammatory disorders. We hypothesized that outcomes would worsen during the lockdown, and that they would differ by underlying disorder category and age. METHODS: Patients attending a specialized neuroinflammatory clinic (n = 314) completed questionnaires (n = 821 responses; Jan 2017-Aug 2020) assessing sleep, anxiety, depression, and physical activity. Respondents had either: childhood-onset chronic or recurrent neuroinflammatory disorders (CRNI), a history of Autoimmune Encephalitis (AE) or Monophasic Acquired Demyelinating Syndromes (monoADS). We performed linear mixed models to examine the association between our outcome measures (sleep, anxiety, depression, and physical activity) and categories of disorder type, sex, age, physical activity, relapses, and time (pre- vs. post- COVID-19 lockdown). Participant ID acted as a random effect, to account for repeated measures. RESULTS: Sleep significantly increased in the first 6 months of the COVID-19 lockdown (F(1, 544)=56.85, P<0.001,). Across the whole group, anxiety and depression did not change with the pandemic, but we found differing trends by age category. Anxiety decreased in teenagers (≥13y) (Z = 3.96, P<0.001), but not for pre-teens. Depression remained higher in teenagers than preteens across both timepoints (F(1, 597)=6.30, p = 0.012). Physical activity levels did not change with the pandemic in comparison to pre-pandemic (F(1, 629)=1.92, P = 0.166). Anxiety was higher in inactive individuals regardless of timing (F(2, 547)=3.74, p = 0.024). CONCLUSION: For youth with neuroinflammatory disorders, the COVID-19 pandemic lockdown resulted in increased hours of nighttime sleep but did not result in significant overall changes in self-reported anxiety or depression. Pre-lockdown, teenagers had higher depression and anxiety scores than preteens. Post-lockdown, anxiety and depression scores decreased in teenagers compared to pre-teens. Physical activity was low both pre- and post-lockdown, and rates of anxiety were higher for inactive participants at both timepoints. Differences based on age suggest that younger children (<13 years) were more negatively affected by the pandemic than older children (≥ 13 years).

Alternatives for Measuring Sitting Accumulation in Workplace Surveys.

OBJECTIVES: To develop and assess the measurement properties of self-report measures of accumulation of sitting time. METHODS: Seven candidate measures were collected in 51 workers from three office environments (79% women) via online questionnaire administered immediately before and after 7-day monitoring periods (activPAL3 24-hour protocol with diary recorded work hours). RESULTS: Three measures had some validity (P < 0.05 vs activPAL): % of sitting in long bouts more than or equal to 30 minutes, sitting strategy frequency (0 to 100), and interruption rate (n/h sitting). Agreement was limited. Some reliability (intraclass correlation or kappa P < 0.05) was seen for these measures, strategy variety (0 to 100), typical day (five categories), and making a conscious effort to sit less (yes/no). CONCLUSIONS: Two brief and one longer option may suit workplace studies requiring self-report measures of sitting accumulation. Validity was weaker for sitting accumulation than sitting time.

Physical Activity in Youth with Multiple Sclerosis receiving the ATOMIC intervention: Social connectedness above all else.

BACKGROUND: Within the pediatric MS population, physical activity (PA) has been associated with positive health outcomes such as lower lesion and relapse rates (Grover et. al., 2015). Recently, associations between variables from a social-cognitive theory (SCT) and levels of PA in youth with multiple sclerosis have been reported (Sikes & Motl, 2020), suggesting a SCT-based intervention may be efficacious in changing PA. We developed and delivered a 12-week SCT-based intervention and sought to gain an understanding of youth's perspectives on PA over time. METHODS: We performed a qualitative analysis on 34 coaching call transcripts from 13 participants as part of a theory-based intervention promoting PA in youth with MS (NCT03137602). Coaching calls were semi-structured and each participant was scheduled to have three coaching calls spaced monthly for three months. We used an inductive content analysis approach to analyze the data (Elo and Kyngas, 2008). RESULTS: General themes from the calls aligned with the SCT constructs. Youth consistently discussed facilitators for changing PA over time, including a positive attitude, goal setting and social connectedness. There was increasing conversation around PA barriers over time including the environment and a lack of time. CONCLUSION: Youth perceptions on PA can be either positive or negative and can change over time. There is an underlying emergence and importance of social connectedness within PA behaviours. Increases in coaching call content related to goal setting suggest a positive effect of coaching and SCT in these areas. Future studies will focus on interactions between SCT constructs, particularly social connectedness and increased physical activity.

The Effect of Creatine Supplementation on Muscle Function in Childhood Myositis: A Randomized, Double-blind, Placebo-controlled Feasibility Study.

OBJECTIVE: To evaluate the feasibility of studying creatine in juvenile dermatomyositis (JDM). Secondary objectives were to determine the effect of creatine on muscle function and metabolism, aerobic capacity, fatigue, physical activity, and quality of life (QOL), as well as its safety. METHODS: We conducted a 6-month, double-blind, randomized, multiple-baseline design; patients were assigned to creatine or placebo. Feasibility was assessed using attended study visits, completed study procedures, and adherence. Muscle function, aerobic capacity, and muscle strength were assessed with standardized exercise tests. Muscle metabolism was assessed using a 31-Phosphorus Magnetic Resonance Spectroscopy protocol. Fatigue, physical activity, and QOL were assessed by questionnaires. Statistical significance was estimated using a randomization (permutation) test. Changes in outcome measures taken at baseline and end-of-study were calculated using paired t-tests. RESULTS: Median (range) adherence to the study drug was 88.5% (20.5-95.5%) and the proportion of subjects with 80% adherence or higher was 76.9%. There were no missed study visits. There were no statistically significant changes in muscle function, strength, aerobic capacity, disease activity, fatigue, physical activity, or QOL while subjects were receiving creatine compared to placebo. There were statistically significant adaptations in muscle metabolism (e.g., decrease in change in muscle pH following exercise, and decrease in phosphate/phosphocreatine ratio) at the end-of-study compared to baseline. There were no significant adverse effects. CONCLUSION: Creatine supplementation in children with JDM is feasible to study, and is safe and well-tolerated; it may lead to improvements in muscle metabolism.

Youth with multiple sclerosis have low levels of fitness.

BACKGROUND: Moderate and vigorous physical activity is associated with improved outcomes in youth with multiple sclerosis (MS). Physical fitness may also influence disease and health outcomes in this population. OBJECTIVES: To determine if there were differences in physical fitness between youth with MS and healthy controls (HC).To examine relationships between physical fitness, physical activity (PA) level, fatigue, depression and disease activity in youth with MS and HC. METHODS: Youth with MS (n = 19) and HC (n = 21) completed tests establishing cardiorespiratory-fitness (VO2peak), endurance via 2-minute walk test, and musculoskeletal strength via grip strength (GS). Questionnaires determined fatigue, depression, and PA levels. Weekly PA level was determined by accelerometry. Tests of differences and correlational analyses were used to evaluate physical fitness. RESULTS: Youth with MS had lower VO2peak (U = 279, p < 0.0001), endurance (t = 2.6, p = 0.02), and higher body mass index (BMI) (t = -5.9, p = 0.001) than HC. Higher VO2peak was associated with higher moderate to vigorous PAaccelerometer in HC (Spearman-Rho = 0.5, p = 0.03), but not in youth with MS (Spearman-Rho = 0.5, p = 0.06). Lower VO2peak and GS were associated with higher disability (Spearman-Rho = -0.6, p = 0.03) and relapses in MS (Spearman-Rho = -0.52, p = 0.04). CONCLUSIONS: Youth with MS have lower levels of fitness, compared with HC. Higher levels of fitness were associated with lower disease activity and disability in youth with MS.

Weekly group tummy time classes are feasible and acceptable to mothers with infants: a pilot cluster randomized controlled trial.

BACKGROUND: The World Health Organization recommends 30 min of tummy time daily for improved motor development and reduced likelihood of plagiocephaly. As only 30% of infants meet this recommendation, parents require strategies and support to increase this proportion. METHODS: The aim of this study was to determine the feasibility, acceptability, and potential efficacy of a group intervention to promote tummy time. The design is a cluster randomized controlled trial with concealed allocation, assessor blinding, and intention-to-treat analysis. Five groups of healthy infants (N = 35, baseline mean (SD) age 5.9 (2.8) weeks) and their mothers attending local mother's groups (Australia) were randomly allocated to the intervention or control group. The intervention group received group tummy time classes in addition to usual care. The control group received usual care with their child and family health nurse. Primary outcomes were intervention feasibility and acceptability. Secondary outcomes were tummy time duration (accelerometry), adherence to physical activity guidelines, head shape, and motor development. Measures were taken at baseline, post-intervention, and when infants were 6 months of age. Analyses were by linear mixed models and Cohen's d statistic. RESULTS: Recruitment, retention, and collection of objective data met feasibility targets. Acceptability was also met with intervention mothers reporting the information, goal planning, and handouts significantly more useful and relevant than control group mothers (p < 0.01). Moderate effect sizes were also found at post-intervention for tummy time duration, adherence to physical activity guidelines and infant ability in prone and supine favoring the intervention group (intervention infants had a mean of 30 min and 30% adherence to guidelines (95% CI 0 to 60.6 min) compared to the control infants who had a mean of 16.6 min and 13% adherence to the guidelines (95% CI 0 to 42.1 min, Cohen's d = 0.5). Limitations were the small sample size, 4-week intervention, limited accelerometer use, and a homogenous sample of participants. CONCLUSION: Group tummy time classes delivered in a mother's group setting were shown to be feasible and acceptable. A larger randomized controlled trial is warranted. TRIAL REGISTRATION: ANZCTR, ACTRN12617001298303p. Registered 11 September 2017.

Temporal features of sitting, standing and stepping changes in a cluster-randomised controlled trial of a workplace sitting-reduction intervention.

BACKGROUND: There is now a body of evidence on the effectiveness of interventions to reduce workplace sitting time. However, there has been limited reporting of how such interventions may impact behaviour both during and outside of work. Sitting, standing and stepping changes following a workplace intervention were examined across five timeframes (work time on work days; non-work time on work days; work days; non-work days; overall (i.e. work and non-work time on all days)), and the relationships between changes during and outside of work was assessed. METHODS: The cluster-randomised controlled trial, 'Stand Up Victoria', delivered a multi-component workplace-delivered intervention that successfully reduced workplace and overall sitting time (relative to controls). Separately, over the five timeframes, changes in device (activPAL3)-assessed outcomes - sitting; prolonged sitting (≥30 min bouts); standing; and, stepping - were compared between intervention (n = 114) and controls (n = 84), along with the time-course of sitting changes during work hours, using mixed models. The potential relationships of changes during work with changes outside of work were examined using compositional data analysis. RESULTS: On workdays, intervention participants significantly (p < 0.05) improved their activity profile relative to controls, with reduced sitting (- 117 min/8-h workday, 95% CI: - 141, - 93) and prolonged sitting (- 77 min/8 h workday, 95% CI: - 101, - 52); increased standing (114 min/8 h workday, 95% CI: 92, 136) and maintenance of stepping (3 min/8 h workday, 95% CI: - 7, 11, p = 0.576). Effects were nearly identical for time at work; similar but slightly weaker for overall; and, small and non-significant outside of work on workdays and non-work days. Improvements occurred at all times, but not equally, during work hours (p < 0.001). Correlations between changes during and outside of work on workdays were very weak in both the intervention group (r = - 0.07) and controls (r = - 0.09). CONCLUSIONS: Sitting time was reduced almost exclusively during work hours (via replacement with standing), with reductions evident during all working hours, to varying degrees. There was no evidence of compensation, with minimal change in activity outside of work, in response to changes in activity at work. Future interventions may benefit from exploring how best to elicit change throughout the whole day, and across work and non-work domains. TRIAL REGISTRATION: This trial was prospectively registered with the Australian New Zealand Clinical Trials register (ACTRN12611000742976) on 15 July 2011.

Benefits of Physical Activity for Depression and Fatigue in Multiple Sclerosis: A Longitudinal Analysis.

OBJECTIVES: To examine the longitudinal relationship between physical activity and fatigue and depression among youth with demyelinating conditions. STUDY DESIGN: From September 2013 to March 2017, we performed a longitudinal study of consecutive youth diagnosed at their first visit with pediatric onset multiple sclerosis (POMS) or monophasic acquired demyelinating syndromes (mono-ADS) at a neuroinflammatory disorders clinic in a tertiary children's hospital. Fatigue was determined at each visit by the Pediatric Quality of Life Multidimensional Fatigue Scale, depressive symptoms by the Center of Epidemiologic Studies Depression Children Rating Scale, and physical activity level by the Godin Leisure Time Exercise Questionnaire. Mixed linear models were used to examine the associations of moderate-to-vigorous physical activity (MVPA) with fatigue and depression over time, adjusting for age, time from incident demyelination, sex, number of relapses, relapse within 30 days, and disability. RESULTS: In 182 patients (48 POMS, age 15 ± 1.7 years, 35 female; and 134 mono-ADS, age 12 ± 3.6 years 67 female) with 538 visits (mean follow-up 3.6 ± 2.7 years and 4.2 ± 3.3 years, respectively), a trajectory of increased fatigue over time was observed in POMS (2.28 points/year, P = .008) and mono-ADS (1.33 points/year, P = .007) patients. Youth with POMS had more depressive symptoms (estimate = 11.4 points, P < .002) than mono-ADS. Depressive symptoms increased over time in female patients with POMS (estimate = 1.4 points/year, P < .02). MVPA was associated with lower depression (-0.09, P < .001) and general fatigue (0.13, P = .02) over time in POMS. CONCLUSIONS: Youth with POMS who have higher levels of MVPA demonstrate lesser depressive symptoms and lower fatigue over time. Our results may inform future interventions to manage mood and fatigue in POMS.

Physical activity for children with chronic disease; a narrative review and practical applications.

BACKGROUND: Physical activity (PA) is associated with a diverse range of health benefits. International guidelines suggest that children should be participating in a minimum of 60 min of moderate to vigorous intensity PA per day to achieve these benefits. However, current guidelines are intended for healthy children, and thus may not be applicable to children with a chronic disease. Specifically, the dose of PA and disease specific exercise considerations are not included in these guidelines, leaving such children with few, if any, evidence-based informed suggestions pertaining to PA. Thus, the purpose of this narrative review was to consider current literature in the area of exercise as medicine and provide practical applications for exercise in five prevalent pediatric chronic diseases: respiratory, congenital heart, metabolic, systemic inflammatory/autoimmune, and cancer. METHODS: For each disease, we present the pathophysiology of exercise intolerance, summarize the pediatric exercise intervention research, and provide PA suggestions. RESULTS: Overall, exercise intolerance is prevalent in pediatric chronic disease. PA is important and safe for most children with a chronic disease, however exercise prescription should involve the entire health care team to create an individualized program. CONCLUSIONS: Future research, including a systematic review to create evidence-based guidelines, is needed to better understand the safety and efficacy of exercise among children with chronic disease.

What strategies do desk-based workers choose to reduce sitting time and how well do they work? Findings from a cluster randomised controlled trial.

BACKGROUND: Large amounts of sitting at work have been identified as an emerging occupational health risk, and findings from intervention trials have been reported. However, few such reports have examined participant-selected strategies and their relationships with behaviour change. METHODS: The Stand Up Victoria cluster-randomised controlled trial was a workplace-delivered intervention comprising organisational, environmental and individual level behaviour change strategies aimed at reducing sitting time in desk-based workers. Sit-stand workstations were provided, and participants (n = 134; intervention group only) were guided by health coaches to identify strategies for the 'Stand Up', 'Sit Less', and 'Move More' intervention targets, including how long they would stand using the workstation. Three-month workplace sitting and activity changes (activPAL3-assessed total sitting, prolonged sitting (i.e., sitting ≥30 min continuously) and purposeful walking) were evaluated in relation to the number (regression analysis) and types of strategies (decision-tree analysis). RESULTS: Over 80 different strategies were nominated by participants. Each additional strategy nominated for the 'Stand Up' intervention target (i.e. number of strategies) was associated with a reduction in prolonged sitting of 27.6 min/8-h workday (95% CI: -53.1, - 2.1, p = 0.034). Types of strategies were categorised into 13 distinct categories. Strategies that were task-based and phone-based were common across all three targets. The decision tree models did not select any specific strategy category as predicting changes in prolonged sitting ('Stand Up'), however four strategy categories were identified as important for total sitting time ('Sit Less') and three strategy categories for purposeful walking ('Moving More'). The uppermost nodes (foremost predictors) were nominating > 3 h/day of workstation standing (reducing total workplace sitting) and choosing a 'Move More' task-based strategy (purposeful walking). CONCLUSIONS: Workers chose a wide range of strategies, with both strategy choice and strategy quantity appearing relevant to behavioural improvement. Findings support a tailored and pragmatic approach to encourage a change in sitting and activity in the workplace. Evaluating participant-selected strategies in the context of a successful intervention serves to highlight options that may prove feasible and effective in other desk-based workplace environments. TRIAL REGISTRATION: This trial was prospectively registered with the Australian New Zealand Clinical Trials register ( ACTRN12611000742976 ) on 15 July 2011.

Strategies for Dealing with Missing Accelerometer Data.

Missing data is a universal research problem that can affect studies examining the relationship between physical activity measured with accelerometers and health outcomes. Statistical techniques are available to deal with missing data; however, available techniques have not been synthesized. A scoping review was conducted to summarize the advantages and disadvantages of identified methods of dealing with missing data from accelerometers. Missing data poses a threat to the validity and interpretation of trials using physical activity data from accelerometry. Imputation using multiple imputation techniques is recommended to deal with missing data and improve the validity and interpretation of studies using accelerometry.

Validity of the Stage of Exercise Scale in Children with Rheumatologic Conditions.

OBJECTIVE: To determine the face, content, and construct validity of the Stages of Exercise Scale (SOES) in children with rheumatologic conditions [juvenile idiopathic arthritis (JIA) and juvenile dermatomyositis (JDM)], and if the validity of the SOES differs by disease type by comparing it with a disease control with a chronic respiratory illness [cystic fibrosis (CF)]. METHODS: Sixty-seven children and adolescents (43 female) ages 11 to 18 years with a diagnosis of either JDM (n = 15), JIA (n = 39), or CF (n = 13) completed the SOES; scales of sensibility, process of change, decisional balance, and self-efficacy; the Child Health Assessment Questionnaire; and patient/physician ratings of disease severity. Physical activity was measured by an accelerometer. Relationships among SOES and measured constructs were determined by ANOVA and with logistical modeling. RESULTS: SOES, decisional balance, and self-efficacy as well as behavioral and cognitive processes from the process of change demonstrated significant differences across the staging subgroups. Disease groups did not significantly differ on the scoring across the SOES. Children and adolescents in higher stages participated in more minutes of vigorous physical activity compared with those in the lower stages. CONCLUSION: The SOES demonstrated good face, content, and construct validity in children and adolescents with rheumatic disease.