A qualitative study of fitness instructors' experiences leading an exercise program for children with juvenile idiopathic arthritis.

Children with arthritis face challenges when they try to increase their physical activity. The study's objective was to identify elements of a successful community-based exercise program for children with arthritis by investigating the perspectives of fitness instructors who led the program. This qualitative study used a phenomenological approach. Four fitness instructors participated in individual interviews. Themes were developed through inductive analytic methods. Three main themes were identified: (a) children with arthritis require encouragement and guidance throughout the program from fitness instructors who understand their arthritis, and support from parents and peers; (b) children need help to overcome their negative perceptions about exercise; and (c) exercise program participation can launch the adoption of a more active lifestyle. Pediatric physiotherapists can encourage the establishment of successful exercise programs for children with arthritis in nonmedical or community environments through the formation of supportive, education-based partnerships with community-based fitness instructors.

Resting and exercise cardiorespiratory function in survivors of congenital diaphragmatic hernia.

Our objective was to study exercise capacity and cardiorespiratory response to exertion in survivors of congenital diaphragmatic hernia (CDH). This was a cross-sectional cohort study of 23 CDH survivors, aged 10-16 years, and 23 gender- and age-matched controls. Exercise testing was performed on a cycle ergometer, with cardiac output measurements made using exponential CO2 rebreathing. Pretest cardiorespiratory assessment was done by echocardiography and pulmonary function testing. Statistical analysis was performed using Student's t-test, regression analysis, and longitudinal model computing with spatial covariance structure. No echocardiographic evidence for pulmonary hypertension was found at rest (right ventricular systolic pressures, 27 +/- 6 mmHg). Mean pulmonary artery diameter on the side of the CDH was significantly smaller than contralaterally, but was within normal range (z-score, 0 +/- 1.1 vs. 1.2 +/- 1.6, P < 0.01). Exercise capacity was mildly reduced in CDH compared to controls and predictive data (maximum workload, 77% +/- 12% vs. 91% +/- 16% of predicted, P < 0.01). Cardiorespiratory response to exertion was not significantly different between groups. In conclusion, most adolescent CDH survivors have nearly normal exercise capacity and cardiorespiratory response to exertion. This study may prove useful in comparisons with future cohorts comprising more severely affected individuals now surviving due to improved neonatal care.

Determination of maximal voluntary ventilation in children with cystic fibrosis.

Maximal voluntary ventilation (MVV) may be determined directly by the sprint method or calculated from pulmonary function data, using the functions MVV = forced expired volume in 1 sec (FEV(1)) x 35 or MVV = FEV(1) x 40. The purpose of this paper was to test the validity of the equation over a wide range of lung function in children. Cystic fibrosis (CF), a chronic lung disease where children typically have a wide range of pulmonary function, was chosen as the study requirement. Spirometric data from 332 children with CF who underwent pulmonary function testing between 1987-2000 were stratified according to disease severity, and box-plots comparing the ratio of MVV to FEV(1) for each category were generated. As results indicated that the equation underestimates true MVV proportionally to the degree of airflow limitation, a new function to predict MVV for this population was derived and tested. The new equation was derived using data from patients who were tested on odd-numbered days (group A). The validity of the new equation was then tested on the patients tested on even-numbered days (group B). To test its validity, the results were compared to the "gold standard" sprint values using a Bland and Altman plot. MVV was expressed as a function of FEV(1) and predicted FEV(1): MVV = 27.7(FEV(1)) + 8.8(PredFEV(1)) (R(2) = 0.98, P < 0.05). In this way, the accuracy of the new equation was confirmed. Whenever possible, we recommend MVV be determined by the sprint method in accordance with ATS guidelines. If this is not feasible, we recommend considering the new prediction equation.

Reliability and validity of the habitual activity estimation scale (HAES) in patients with cystic fibrosis.

PURPOSE: To understand potential benefits of exercise in the cystic fibrosis (CF) population, there needs to be accurate methods to quantify it. The Habitual Activity Estimation Scale (HAES) questionnaire has been shown to be a feasible tool to measure physical activity however the reliability and validity have yet to be determined in the CF population. METHODS: Fourteen (seven male, seven female) patients aged 16.2 +/- 4.2 years with CF participated in this study. Participants were clinically stable at the time of the study and participating in their habitual physical activity. To assess reliability, patients completed the HAES and a validated 3-day activity diary, and wore an ActiGraph Accelerometer for two consecutive weeks. Validity was assessed by comparing the activity results of each of the three instruments over a single week time period. RESULTS: ICC estimates of reliability for the HAES, diary, and accelerometer were 0.72 (P < 0.0001), 0.76 (P < 0.0001), 0.63 (P < 0.0001), respectively. Validity analysis indicated that there were significant relationships between the participants' activity results as estimated by the HAES, diary and accelerometer. Further, significant relationships were detected between activity measures when broken into morning, afternoon, or evening periods, and between measures from weekday or weekend days. There were also significant relationships among the three instruments when recording different activity levels (somewhat inactive, somewhat active, and very active). CONCLUSION: The findings of this study suggest that the HAES questionnaire is a reliable and valid instrument that can be used to assess activities of varying intensity in patients with CF.

The effects of vigorous exercise training on physical function in children with arthritis: a randomized, controlled, single-blinded trial.

OBJECTIVE: To examine the effectiveness of high-intensity aerobic training compared with low-intensity training in terms of energy cost of locomotion, peak oxygen uptake, peak power, and self-reported physical function in children with juvenile idiopathic arthritis (JIA). METHODS: Eighty children with JIA, ages 8-16 years, were enrolled in a randomized, single-blind controlled trial. Both groups participated in a 12-week, 3-times-weekly training program consisting of high-intensity aerobics in the experimental group and qigong in the control group. Subjects underwent exercise testing measuring submaximal oxygen uptake at 3 km/hour (VO(2submax)) as the primary outcome, maximal oxygen uptake, and peak power at the beginning and end of the program. Physical function was measured using the Child Health Assessment Questionnaire (C-HAQ). RESULTS: The exercise program was well tolerated in both groups. There was no difference in VO(2submax) or any other exercise testing measures between the groups through the study period and no indication of improvement. Both groups showed significant improvements in C-HAQ with no difference between the groups. Adherence was higher in the control group than the experimental group. CONCLUSION: Our findings suggest that activity programs with or without an aerobic training component are safe and may result in an important improvement in physical function. The intensity of aerobic training did not seem to provide any additional benefits, but higher adherence in the qigong program may suggest that less intensive regimens are easier for children with JIA to comply with, and provide a degree of benefit equivalent to more intensive programs.

Reliability of exercise testing and functional activity questionnaires in children with juvenile arthritis.

OBJECTIVE: To determine the reliability of formal exercise testing and the reliability of functional and activity questionnaires in children with juvenile idiopathic arthritis (JIA). METHODS: Children with JIA of any subtype ages 8-16 years who were recruited to a randomized trial comparing different exercise therapies participated in 2 preintervention sessions of exercise testing 2-6 weeks apart. Exercise testing included 1) submaximal oxygen uptake (VO(2submax)), 2) peak VO(2) (VO(2peak)), and 3) anaerobic power using modified Wingate tests (W(ant)). Two physical function questionnaires (the Childhood Health Assessment Questionnaire [C-HAQ] and Revised Activity Scale for Kids [ASK]) and 1 daily physical activity questionnaire (the Habitual Activity Estimation Scale [HAES]) were also completed at these times. Test-retest reliability was assessed using type 3, intrarater intraclass correlation coefficient (ICC(3,1)) and Bland and Altman plots were used to determine limits of agreement. RESULTS: Data were available for 74 patients (58 girls). VO(2submax), VO(2peak), and W(ant) demonstrated high reliability (ICC(3,1) 0.82, 0.91, and 0.94, respectively). C-HAQ and ASK questionnaires also had very high reliability (ICC(3,1) 0.82 and 0.91, respectively). The HAES demonstrated low reliability for total activity score (ICC(3,1) 0.15) and moderate reliability when the number of very active hours was analyzed separately (ICC(3,1) 0.59). CONCLUSION: Results of this investigation suggest that exercise testing and functional questionnaires in children with JIA are consistent and reliable. Reliability of the HAES total score was poor, but moderate when the very active hours subscale score was used.

Fetal response to maternal exercise in pregnancies with uteroplacental insufficiency.

OBJECTIVE: The purpose of this study was to determine the fetal response to submaximal maternal exercise at 22 to 26 weeks in pregnancies with abnormal uterine artery Doppler. STUDY DESIGN: This was a prospective comparison of singleton pregnancies with uteroplacental vascular insufficiency (UPVI) (mean uterine pulsatility index [PI] values >1.45 [n = 12]) and those with normal uterine artery Doppler (n = 23). Maternal and fetal cardiovascular responses to 5 minutes of steady state cycling at 10% and at 15% of predicted work rate maximum were studied. RESULTS: Umbilical artery Doppler deteriorated after exercise in patients with UPVI (pre PI 1.4 [0.35-2.14], post PI 1.64 [0.45-2.18]). Three (25%) had transient absent-end diastolic flow (AEDF) in umbilical artery, 2 of which developed early-onset intrauterine growth restriction (IUGR) with AEDF. Fetal cardiac output studies remained stable during the examinations. CONCLUSION: Submaximal steady state exercise had a transient deleterious effect in a subset of women with uteroplacental vascular insufficiency destined to develop early-onset IUGR.