Fitkids exercise therapy program: Creating possibilities for youth with chronic medical conditions

Elles Maria Willemien Kotte

    Research output: ThesisDoctoral thesis 2 (Research NOT UU / Graduation UU)


    PART 1. FITKIDS INTERVENTION In chapter 3, the effects of the Fitkids intervention were investigated in a cross-sectional observational study. Children and adolescents with CMCs received a graded exercise program for 6 months. After 6 months of training, significant improvements in health-related fitness, walking capacity, and HRQoL were found. Preliminary data outlined in chapter 7 reveal that there is no distinct relationship between participation in the Fitkids intervention and an increase in daily physical activity during the intervention period. Unpublished data of that study, however, pointed out that half of the included children were able to find an appropriate sport to participate in after the Fitkids intervention was completed. PART 2. FITKIDS TREADMILL TEST In chapter 4 it was concluded that the Fitkids Treadmill Test (FTT) is a useful treadmill protocol with good validity and reproducibility in children and adolescents who are healthy. The VO2peak reached during the FTT showed excellent correlation with VO2peak reached during the Bruce protocol. Backward multiple regression analysis provided the following prediction equations that can be used to estimate VO2peak (L·min-1) from time to exhaustion (TTE) reached on the FTT: for boys, VO2peak FTT = -0.748 + (0.117 × TTE FTT) + (0.032 × body mass) + 0.263; for girls, VO2peak FTT = -0.748 + (0.117 × TTE FTT) + (0.032 × body mass). Reliability statistics for the FTT showed an ICC of .985 for TTE. Bland-Altman analysis showed a mean bias of -0.07 minutes, with limits of agreement between +1.30 and -1.43 minutes. In chapter 5 we described sex- and age-related normative values for FTT performance in children and adolescents who were healthy, typically developing, and between 6-18 yr. PART 3. NEW MEASUREMENT TOOLS: APPLICABILITY IN CLINICAL PRACTICE In chapter 6, the clinical utility of the FTT was investigated and this study also explored potential factors affecting the use of the FTT in clinical practice. To assess the utility of the FTT, 2 indicators were used. The first indicator was exercise duration, the second was maximal effort (i.e., HRpeak >180 beats·min-1). The Indicators were considered sufficient when reached by 75% of the included children in each of the diagnostic groups. The first indicator was successful in each diagnostic group. The second indicator was only reached in children with metabolic diseases (92%) and neuromuscular diseases (76%). The most important facilitator to the use of the FTT was the fact that the great majority was convinced of the additional value of the FTT. Main barriers were physical therapists’ attitude (resistance to change/ lack of experience) and, on the environmental level, the absence of a treadmill ergometer within the physical therapist’s practice. In chapter 7, the added value of using an accelerometer to monitor physical activity in children with CMCs in physical therapy practice was explored in comparison to subjective physical activity questionnaires. In addition, this study focused on the feasibility of using an accelerometer to monitor free-living physical activity in children with CMCs. The results showed a significant difference between subjective measures and objective measures of moderate to vigorous physical activity (P =.005) The in-depth analysis showed that the value of using objective data lies in more detailed description of physical activity per day and differences between weekdays and weekend days. Feasibility of the accelerometer was limited due to difficulties in applying the accelerometer, reluctance of children and their parents to wear the accelerometer for 7 days and technical difficulties in reading and charging. It was concluded that objectively measured physical activity has additional value in comparison with subjective measured physical activity as it gives therapists more detailed information.
    Original languageEnglish
    Awarding Institution
    • University Medical Center (UMC) Utrecht
    • Veenhof, Cindy, Primary supervisor
    • Takken, T, Co-supervisor
    • de Groot, J.F., Co-supervisor
    Award date14 Nov 2019
    Place of Publication[Utrecht]
    Print ISBNs978-94-028-1695-2
    Publication statusPublished - 14 Nov 2019


    • Child
    • Chronic condition
    • Disabilities
    • Exercise therapy
    • exercise testing
    • Fitkids Treadmill Test
    • Standardized outcome measure
    • Clinical practice
    • Physical behavior


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