In this thesis we analyzed clinimetric measurement properties of physical fitness tests in wheelchair-using youth with SB. Furthermore, the amount of physical behavior in wheelchair-using youth with SB was quantified and associations with age, gender, VO2peak and Hoffer classification were evaluated. Finally, we described the factors associated with physical behavior in youth with SB and youth with physical disabilities, after which the evidence of interventions to improve physical behavior in youth with physical disabilities was analyzed. This last chapter presents the theoretical and clinical implications. At the end, methodological considerations and directions for further research will be discussed after which the overall conclusion is presented.
Background: Cardiovascular risk factors are associated with physical fitness and, to a lesser extent, physical activity. Lifestyle interventions directed at enhancing physical fitness in order to decrease the risk of cardiovascular diseases should be extended. To enable the development of effective lifestyle interventions for people with cardiovascular risk factors, we investigated motivational, social-cognitive determinants derived from the Theory of Planned Behavior (TPB) and other relevant social psychological theories, next to physical activity and physical fitness. Methods: In the cross-sectional Utrecht Police Lifestyle Intervention Fitness and Training (UP-LIFT) study, 1298 employees (aged 18 to 62) were asked to complete online questionnaires regarding social-cognitive variables and physical activity. Cardiovascular risk factors and physical fitness (peak VO2) were measured. Results: For people with one or more cardiovascular risk factors (78.7% of the total population), social-cognitive variables accounted for 39% (p < .001) of the variance in the intention to engage in physical activity for 60 minutes every day. Important correlates of intention to engage in physical activity were attitude (beta = .225, p < .001), self-efficacy (beta = .271, p < .001), descriptive norm (beta = .172, p < .001) and barriers (beta = -.169, p < .01). Social-cognitive variables accounted for 52% (p < .001) of the variance in physical active behaviour (being physical active for 60 minutes every day). The intention to engage in physical activity (beta = .469, p < .001) and self-efficacy (beta = .243, p < .001) were, in turn, important correlates of physical active behavior. In addition to the prediction of intention to engage in physical activity and physical active behavior, we explored the impact of the intensity of physical activity. The intentsity of physical activity was only significantly related to physical active behavior (beta = .253, p < .01, R2 = .06, p < .001). An important goal of our study was to investigate the relationship between physical fitness, the intensity of physical activity and social-cognitive variables. Physical fitness (R2 = .23, p < .001) was positively associated with physical active behavior (beta = .180, p < .01), self-efficacy (beta = .180, p < .01) and the intensity of physical activity (beta = .238, p < .01). For people with one or more cardiovascular risk factors, 39.9% had positive intentions to engage in physical activity and were also physically active, and 10.5% had a low intentions but were physically active. 37.7% had low intentions and were physically inactive, and about 11.9% had high intentions but were physically inactive. Conclusions: This study contributes to our ability to optimize cardiovascular risk profiles by demonstrating an important association between physical fitness and social-cognitive variables. Physical fitness can be predicted by physical active behavior as well as by self-efficacy and the intensity of physical activity, and the latter by physical active behavior. Physical active behavior can be predicted by intention, self-efficacy, descriptive norms and barriers. Intention to engage in physical activity by attitude, self-efficacy, descriptive norms and barriers. An important input for lifestyle
Objectives: Health problems in patients with heritable connective tissue disorders (HCTD) are diverse and complex and might lead to lower physical activity (PA) and physical fitness (PF). This study aimed to investigate the PA and PF of children with heritable connective tissue disorders (HCTD).Methods: PA was assessed using an accelerometer-based activity monitor (ActivPAL) and the mobility subscale of the Pediatric Evaluation of Disability Inventory Computer Adaptive Test (PEDI-CAT). PF was measured in terms of cardiovascular endurance using the Fitkids Treadmill Test (FTT); maximal hand grip strength, using hand grip dynamometry (HGD) as an indicator of muscle strength; and motor proficiency, using the Bruininks-Oseretsky Test of Motor Proficiency-2 (BOTMP-2).Results: A total of 56 children, with a median age of 11.6 (interquartile range [IQR], 8.8–15.8) years, diagnosed with Marfan syndrome (MFS), n = 37, Loeys-Dietz syndrome (LDS), n = 6, and genetically confirmed Ehlers-Danlos (EDS) syndromes, n = 13 (including classical EDS n = 10, vascular EDS n = 1, dermatosparaxis EDS n = 1, arthrochalasia EDS n = 1), participated. Regarding PA, children with HCTD were active for 4.5 (IQR 3.5–5.2) hours/day, spent 9.2 (IQR 7.6–10.4) hours/day sedentary, slept 11.2 (IQR 9.5–11.5) hours/day, and performed 8,351.7 (IQR 6,456.9–1,0484.6) steps/day. They scored below average (mean (standard deviation [SD]) z-score −1.4 (1.6)) on the PEDI-CAT mobility subscale. Regarding PF, children with HCTD scored well below average on the FFT (mean (SD) z-score −3.3 (3.2)) and below average on the HGD (mean (SD) z-score −1.1 (1.2)) compared to normative data. Contradictory, the BOTMP-2 score was classified as average (mean (SD) z-score.02 (.98)). Moderate positive correlations were found between PA and PF (r(39) = .378, p < .001). Moderately sized negative correlations were found between pain intensity and fatigue and time spent actively (r(35) = .408, p < .001 and r(24) = .395 p < .001, respectively).Conclusion: This study is the first to demonstrate reduced PA and PF in children with HCTD. PF was moderately positively correlated with PA and negatively correlated with pain intensity and fatigue. Reduced cardiovascular endurance, muscle strength, and deconditioning, combined with disorder-specific cardiovascular and musculoskeletal features, are hypothesized to be causal. Identifying the limitations in PA and PF provides a starting point for tailor-made interventions.
