Janke F. de Groot

Muscle strength, aerobic capacity and physical activity in independent ambulating children with lumbosacral spina bifida

Purpose. This cross-sectional study investigates deficits and associations in muscle strength, 6-minute walking distance (6MWD), aerobic capacity (VO2peak), and physical activity (PA) in independent ambulatory children with lumbosacral spina bifida. Method. Twenty-tree children participated (13 boys, 10 girls). Mean age (SD): 10.4 (±3.1) years. Muscle strength (manual muscle testing and hand-held dynamometry), 6MWD, VO2peak (maximal exercise test on a treadmill), and PA (quantity and energy expenditure [EE]), were measured and compared with aged-matched reference values. Results. Strength of upper and lower extremity muscles, and VO2peak were significantly lower compared to reference values. Mean Z-scores ranged from −1.2 to −2.9 for muscle strength, and from −1.7 to −4.1 for VO2peak. EE ranged from 73 – 84% of predicted EE. 6MWD was significantly associated with muscle strength of hip abductors and foot dorsal flexors. VO2peak was significantly associated with strength of hip flexors, hip abductors, knee extensors, foot dorsal flexors, and calf muscles. Conclusions. These children have significantly reduced muscle strength, 6MWD, VO2peak and lower levels of PA, compared to reference values. VO2peak and 6MWD were significantly associated with muscle strength, especially with hip abductor and ankle muscles. Therefore, even in independent ambulating children training on endurance and muscle strength seems indicated.

Factors associated with physical activity in children and adolescents with a physical disability: a systematic review

The aim of this review was to summarize the important factors associated with participation in physical activity in children and adolescents with physical disabilities.

Treadmill Testing of Children Who Have Spina Bifida and Are Ambulatory: Does Peak Oxygen Uptake Reflect Maximum Oxygen Uptake?

Background: Earlier studies have demonstrated low peak oxygen uptake (V̇o2peak) in children with spina bifida. Low peak heart rate and low peak respiratory exchange ratio in these studies raised questions regarding the true maximal character of V̇o2peak values obtained with treadmill testing. Objective: The aim of this study was to determine whether the V̇o2peak measured during an incremental treadmill test is a true reflection of the maximum oxygen uptake (V̇o2max) in children who have spina bifida and are ambulatory. Design: A cross-sectional design was used for this study. Methods: Twenty children who had spina bifida and were ambulatory participated. The V̇o2peak was measured during a graded treadmill exercise test. The validity of V̇o2peak measurements was evaluated by use of previously described guidelines for maximum exercise testing in children who are healthy, as well as differences between V̇o2peak and V̇o2 during a supramaximal protocol (V̇o2supramaximal). Results: The average values for V̇o2peak and normalized V̇o2peak were, respectively, 1.23 L/min (SD=0.6) and 34.1 mL/kg/min (SD=8.3). Fifteen children met at least 2 of the 3 previously described criteria; one child failed to meet any criteria. Although there were no significant differences between V̇o2peak and V̇o2supramaximal, 5 children did show improvement during supramaximal testing. Limitations: These results apply to children who have spina bifida and are at least community ambulatory. Conclusions: The V̇o2peak measured during an incremental treadmill test seems to reflect the true V̇o2max in children who have spina bifida and are ambulatory, validating the use of a treadmill test for these children. When confirmation of maximal effort is needed, the addition of supramaximal testing of children with disability is an easy and well-tolerated method.

Reproducibility of Maximal and Submaximal Exercise Testing in “Normal Ambulatory” and “Community Ambulatory” Children and Adolescents With Spina Bifida: Which Is Best for the Evaluation and Application of Exercise Training?

Background With emerging interest in exercise and lifestyle interventions for children and adolescents with spina bifida, there is a need for appropriate measurements in exercise testing. Objective The purpose of this study was to assess both reliability and agreement of maximal and submaximal exercise measures in “normal ambulatory” and “community ambulatory” children and adolescents with spina bifida. Design This was a reproducibility study. Methods Twenty-three children and adolescents with spina bifida (10 normal ambulatory and 13 community ambulatory) participated in the study. Maximal exercise outcomes were measured using a graded treadmill test. Peak measures (peak oxygen uptake [V̇o2peak], peak heart rate [HRpeak], heart rate response [HRR], and oxygen pulse) were recorded. For submaximal measures, heart rate (HR) and oxygen uptake (V̇o2) at the ventilatory threshold and oxygen uptake efficiency slope (OUES) were derived from the maximal measures. Functional performance was measured as the 6-minute walking distance and the maximal speed during the treadmill test. After checking for normality and heteroscedasticity, paired t tests, intraclass correlation coefficients (ICCs), and the smallest detectable difference (SDD) or the coefficient of variation (CV) were calculated. Results Performance measures showed good reliability and agreement. For maximal measures, acceptable ICCs were found for all measures. For submaximal measures, only HR at the ventilatory threshold showed an ICC of less than .80. Agreement showed a CV of less than 10% for all measures, except for V̇o2 at the ventilatory threshold, HRR, and OUES. Limitations Limitations of the study include missing data due to equipment failure. Furthermore, the outcomes were limited to normal ambulatory and community ambulatory children and adolescents with spina bifida. Conclusions Both maximal and submaximal measures of exercise testing can be used for discriminative purposes in ambulatory children and adolescents with spina bifida. For evaluative purposes, HR measures are superior to V̇o2 measures, while taking into account the individual variation of 5% to 8%. The SDD was 0.5 km/h for peak speed and 36.3 m for 6-minute walking distance. Heart rate response, oxygen pulse, and OUES are not recommended in the evaluation of exercise testing in this population.

Personal and environmental factors to consider when aiming to improve participation in physical activity in children with Spina Bifida : a qualitative study

BackgroundYouth with spina bifida (SB) are less fit and active than other groups with childhood disability. While recent studies have shown benefits of exercise training, the increased fitness levels do not sustain or lead to increased levels of physical activity (PA) in these children. Therefore, it seems important to explore which factors are associated with participation in PA (or lack of) in youth with SB. The objective of this study is to describe both personal and environmental factors that are important for participation in physical activity as experienced by these children and their parents, in order to better develop intervention strategies to improve participation in PA in youth with SB.MethodsEleven semi-structured interviews with parents of children with SB aged 4–7 years, nine focus groups with youth with SB (n = 33, age 8–18 years) and eight focus groups with their parents (n = 31) were conducted, recorded and transcribed verbatim. Two independent researchers analyzed the data. Central themes for physical activity were constructed, using the model for Physical Activity for Persons with a Disability (PAD model) as a background scheme.ResultsData showed that youth with SB encountered both personal and environmental factors associated with participation in PA on all levels of the PAD model. Bowel and bladder care, competence in skills, sufficient fitness, medical events and self-efficacy were important personal factors. Environmental factors that were associated with physical activity included the contact with and support from other people, the use of assistive devices for mobility and care, adequate information regarding possibilities for adapted sports and accessibility of playgrounds and sports facilities.ConclusionsOur findings suggest that a variety of both personal and environmental factors were either positively or negatively associated with participation in PA. An individual approach, assessing possibilities rather than overcoming barriers within and surrounding the child may be a good starting point when setting up intervention programs to improve participation in PA. Therefore, assessment of both personal and environmental factors associated with physical activity should be standard care within multidisciplinary intervention programs aimed to encourage healthy active lifestyles in youth with SB.

The six-minute walk test in paediatric populations

The six-minute walk test (6MWT) is a self-paced, submaximal exercise test used to assess functional exercise capacity in patients with chronic diseases (Chang 2006, Solway et al 2001). It has been used widely in adults, and is being utilised increasingly in paediatric populations; it has been used as an estimate of physical fitness in, for example, children with severe cardiopulmonary disease, cystic fibrosis, and juvenile idiopathic arthritis (Hassan et al 2010).

Sport-2-Stay-Fit study : Health effects of after-school sport participation in children and adolescents with a chronic disease or physical disability

BackgroundChildren and adolescents with a chronic disease or physical disability have lower fitness levels compared to their non-disabled peers. Low physical fitness is associated with reduced physical activity, increased cardiovascular diseases, and lower levels of both cognitive and psychosocial functioning. Moreover, children and adolescents with a chronic disease or physical disability participate less in both recreational and competitive sports. A variety of intervention studies have shown positive, but only temporary, effects of training programs. Next to issues related to the chronic condition itself, various personal and environmental factors play a key role in determining the extent to which they participate in sports or physical activities. Due to these barriers, sport participation in the immediate after-school hours seems to be a feasible solution to get these children and adolescents physical active structurally. To investigate if an after school sport program can sustain the positive effects of an intervention, a standardized interval training will be given to improve physical fitness levels. High-intensity Interval Training (HIT) is superior to moderate-intensity continuous training in improving physical fitness in patients with chronic diseases. Therefore, the Sport-2-Stay-Fit study will investigate whether after school sport participation can increase the sustainability of a HIT program in children and adolescents with a chronic disease or physical disability.MethodsThe Sport-2-Stay-Fit study is a clinical controlled trial. A total of 74 children and adolescents in the age of 6–19 years with a chronic disease or physical disability will be included. This could be either a cardiovascular, pulmonary, metabolic, musculoskeletal or neuromuscular disorder. Both children and adolescents who are ambulatory or propelling a manual wheelchair will be included. All participants will follow a HIT program of eight weeks to improve their physical fitness level. Thereafter, the intervention group will participate in sport after school for six months, while the control group receives assessment only. Measurements will take place before the HIT, directly after, as well as, six months later. The primary objective is anaerobic fitness. Secondary objectives are agility, aerobic fitness, strength, physical activity, cardiovascular health, cognitive functioning, and psychosocial functioning.DiscussionIf effective, after school sport participation following a standardized interval training could be implemented on schools for special education to get children and adolescents with a chronic disease or physical disability active on a structural basis.Trial registrationThis trial is registered at the Dutch Trial Register #NTR4698.

Arm crANkING VErSuS WHEElcHAIr ProPulSIoN For tEStING AEroBIc FItNESS IN cHIldrEN WItH SPINA BIFIdA WHo ArE WHEElcHAIr dEPENdENt

OBJECTIVE To determine the best test performance and feasibility using a Graded Arm Cranking Test vs a Graded Wheelchair Propulsion Test in young people with spina bifida who use a wheelchair, and to determine the reliability of the best test. DESIGN Validity and reliability study. SUBJECTS Young people with spina bifida who use a wheelchair. METHODS Physiological responses were measured during a Graded Arm Cranking Test and a Graded Wheelchair Propulsion Test using a heart rate monitor and calibrated mobile gas analysis system (Cortex Metamax). For validity, peak oxygen uptake (VO2peak) and peak heart rate (HRpeak) were compared using paired t-tests. For reliability, the intra-class correlation coefficients, standard error of measurement, and standard detectable change were calculated. RESULTS VO2peak and HRpeak were higher during wheelchair propulsion compared with arm cranking (23.1 vs 19.5 ml/kg/min, p = 0.11; 165 vs 150 beats/min, p < 0.05). Reliability of wheelchair propulsion showed high intra-class correlation coefficients (ICCs) for both VO2peak (ICC = 0.93) and HRpeak (ICC = 0.90). CONCLUSION This pilot study shows higher HRpeak and a tendency to higher VO2peak in young people with spina bifida who are using a wheelchair when tested during wheelchair propulsion compared with arm cranking. Wheelchair propulsion showed good reliability. We recommend performing a wheelchair propulsion test for aerobic fitness testing in this population.

The associations of cardiorespiratory fitness, adiposity and sports participation with arterial stiffness in youth with chronic diseases or physical disabilities:

Background The evidence on the associations of cardiorespiratory fitness, body adiposity and sports participation with arterial stiffness in children and adolescents with chronic diseases or physical disabilities is limited. Methods Altogether 140 children and adolescents with chronic diseases or physical disabilities participated in this cross-sectional study. Cardiorespiratory fitness was assessed using maximal exercise test with respiratory gas analyses either using shuttle run, shuttle ride, or cycle ergometer test. Cardiorespiratory fitness was defined as peak oxygen uptake by body weight or fat-free mass. Body adiposity was assessed using waist circumference, body mass index standard deviation score and body fat percentage. Sports participation was assessed by a questionnaire. Aortic pulse wave velocity and augmentation index were assessed by a non-invasive oscillometric tonometry device. Results Peak oxygen uptake/body weight (standardised regression coefficient β −0.222, 95% confidence interval (CI) −0.386 to −0.059, P = 0.002) and peak oxygen uptake/fat-free mass (β −0.173, 95% CI −0.329 to −0.017, P = 0.030) were inversely and waist circumference directly (β 0.245, 95% CI 0.093 to 0.414, P = 0.002) associated with aortic pulse wave velocity. However, the associations of the measures of cardiorespiratory fitness with aortic pulse wave velocity were attenuated after further adjustment for waist circumference. A higher waist circumference (β −0.215, 95% CI −0.381 to −0.049, P = 0.012) and a higher body mass index standard deviation score (β 0.218, 95% CI −0.382 to −0.054, P = 0.010) were related to lower augmentation index. Conclusions Poor cardiorespiratory fitness and higher waist circumference were associated with increased arterial stiffness in children and adolescents with chronic diseases and physical disabilities. The association between cardiorespiratory fitness and arterial stiffness was partly explained by waist circumference.

Effects of the Fitkids Exercise Therapy Program on Health-Related Fitness, Walking Capacity, and Health-Related Quality of Life

Background Children with disabilities have an increased risk for reduced fitness and reduced health-related quality of life (HRQoL). Fitkids, a nationwide exercise therapy program in the Netherlands, was developed to improve fitness and HRQoL in children with disabilities. Objective The study objective was to determine the effects of the Fitkids program on health-related fitness, walking capacity, and HRQoL in children with disabilities or chronic conditions. Design This was a quasi-experimental single-group longitudinal study. Methods Fifty-two children and adolescents who were referred to the Fitkids program participated in this study. Participants received a graded exercise training program for 6 months, with frequencies of 1 hour 2 times per week in the first 3 months and 1 hour per week during months 4 to 6. Health-related fitness (aerobic fitness, anaerobic fitness, and muscle strength), walking capacity, and HRQoL were evaluated at baseline and after 3 and 6 months of training. Multilevel modeling was used to quantify the contributions of repeated measures, participants, and Fitkids centers to variations in health-related fitness, walking capacity, and HRQoL during the intervention period. The models were adjusted for sex, height, and weight. Results After 6 months of training, significant intervention effects were found for aerobic fitness, anaerobic fitness, and muscle strength. A significant effect also was found for walking capacity. On the HRQoL measure, significant improvements were found for the self-reported and parent-reported physical and emotion domains and for the parent-reported total score for HRQoL. Limitations No control group was included in this study. Conclusions The Fitkids exercise therapy program has significantly improved health-related fitness, walking capacity, and HRQoL in children and adolescents with chronic conditions or disabilities.