Is Motor Performance in 5.5-Year-Old Children Associated with the Presence of Generalized Joint Hypermobility?

OBJECTIVE: To determine the prevalence of generalized joint hypermobility (GJH) in Dutch children aged 5.5 years, and to examine the association between GJH and motor performance and development over time. STUDY DESIGN: A prospective cohort of 249 children was recruited. GJH was assessed with the Beighton test at age 5.5 years. Motor performance was evaluated at age 2.0 years using the Bayley Scales of Infant Development, Second Edition and at age 5.5 years using the Movement Assessment Battery for Children-Second Edition (subscore categories: manual dexterity, aiming and catching, and static and dynamic balance). RESULTS: In 249 children, the prevalence of GJH, defined by the Beighton test score, was 34.1% for a score ≥ 4, 22.5% for a score ≥ 5, and 16.5% for a score ≥ 6. No significant association was found between GJH and total motor performance. Manual dexterity in girls (Beighton score ≥ 4) was positively associated with higher level of motor performance (ß [SE] = 0.38 [0.17]; P = .028), ranging from +0.04 SD to +0.72 SD, even after correction for covariates. A significant interaction between GJH and body mass index (BMI) growth was found, indicating that the effect of GJH on the rate of development of motor performance declines with increasing BMI growth (ß = 0.05 [0.02]; P = .031). CONCLUSION: In this healthy pediatric cohort, GJH was present in one-third of the sample, and no significant association was found between GJH and total motor performance. The effect of GJH on the rate of development of motor performance appears to decline with increasing BMI growth. Longitudinal prospective studies are recommended to detect influences of GJH on motor performance over time, as well as the influence of body composition and Beighton cutoff points.

Aerobic capacity in children with hemophilia.

OBJECTIVE: To determine whether aerobic capacity is normal in boys with different types of hemophilia compared with healthy peers and whether the level of aerobic capacity correlates with the amount of physical activity, joint health status, muscle strength, and anthropometrics. STUDY DESIGN: 47 patients (mean [SD] age, 12.9 [3.2] years; age range, 8.2-17.4 years) from the "Van Creveldkliniek" of the University Medical Center Utrecht, participated. Anthropometry, muscle strength, joint impairment, functional ability, and aerobic capacity were measured. The amount of energy expenditure during daily living was assessed. RESULTS: All boys were able to perform at maximal or near-maximal level on exercise tests, and none of them reported bleeds or other adverse events. Relative peak oxygen, peak heart rate, and peak working capacity were significantly lower compared with healthy control subjects. 30% had Z-scores >2 for weight. Total muscle strength was normal, and almost no joint impairment and no decrease in functional ability were found. CONCLUSION: The aerobic capacity of children with hemophilia is still lower than the normal population, whereas their overall muscle strength is comparable with healthy peers. The functional ability does not differ from healthy peers, and joint health status showed very minor impairments. A substantial proportion of Dutch children with hemophilia was overweight, without showing a reduction in the amount of self-reported physical activities.

Physical training in children with osteogenesis imperfecta.

OBJECTIVE: To study the effects of a physical training program on exercise capacity, muscle force, and subjective fatigue levels in patients with mild to moderate forms of osteogenesis imperfecta (OI). STUDY DESIGN: Thirty-four children with OI type I or IV were randomly assigned to either a 12-week graded exercise program or care as usual for 3 months. Exercise capacity and muscle force were studied; subjective fatigue, perceived competence, and health-related quality of life were secondary outcomes. All outcomes were measured at baseline (T = 0), after intervention (T = 1), and after 6 and 9 months (T = 2 and T = 3, respectively). RESULTS: After intervention (T = 1), peak oxygen consumption (VO2peak), relative VO2peak (VO2peak/kg), maximal working capacity (Wmax), and muscle force were significantly improved (17%, 18%, 10%, and 12%, respectively) compared with control values. Subjective fatigue decreased borderline statistically significantly. Follow-up at T = 2 showed a significant decrease of the improvements measured at T = 1 of VO2peak, but VO2peak/kg, Wmax, and subjective fatigue showed no significant difference. At T = 3, we found a further decrease of the gained improvements. CONCLUSION: A supervised training program can improve aerobic capacity and muscle force and reduces levels of subjective fatigue in children with OI type I and IV in a safe and effective manner.

Cardiopulmonary exercise capacity, muscle strength, and physical activity in children and adolescents with achondroplasia.

OBJECTIVE: To study in children with achondroplasia the response to exercise and muscle strength compared with healthy peers and to describe the relation between exercise capacity, anthropometric factors, and physical activity. STUDY DESIGN: Patients (7 boys and 10 girls; mean age, 11.8 +/- 3.3 years) with achondroplasia performed a maximal treadmill exercise test. Anthropometric variables and muscle strength were measured and compared with the general population. The level of everyday physical activity was measured by using a diary. Functional ability was measured by using the Activity Scale for Kids. RESULTS: The exercise capacity of the children with achondroplasia was significantly reduced compared with reference values. All anthropometrical measurements differed significantly from reference values. There was a decrease in muscle strength in almost all muscle groups. We found a reduced physical activity level and impairments in functional ability. CONCLUSIONS: Cardiopulmonary exercise capacity and muscle strength in children with achondroplasia was reduced compared with reference values. Children with achondroplasia have a unique response to exercise. Clinicians should take these characteristic differences into account when the exercise capacity of subjects with achondroplasia is being tested.

Cardiopulmonary fitness and muscle strength in patients with osteogenesis imperfecta type I.

OBJECTIVE: To evaluate cardiopulmonary function, muscle strength, and cardiopulmonary fitness (VO 2 peak) in patients with osteogenesis imperfecta (OI). STUDY DESIGN: In 17 patients with OI type I (mean age 13.3 +/- 3.9 years) cardiopulmonary function was assessed at rest using spirometry, plethysmography, electrocardiography, and echocardiography. Exercise capacity was measured using a maximal exercise test on a bicycle ergometer and an expired gas analysis system. Muscle strength in shoulder abductors, hip flexors, ankle dorsal flexor, and grip strength were measured. All results were compared with reference values. RESULTS: Cardiopulmonary function at rest was within normal ranges, but when it was compared with normal height for age and sex, vital capacities were reduced. Mean absolute and relative VO 2 peak were respectively -1.17 (+/- 0.67) and -1.41 (+/- 1.52) standard deviations lower compared with reference values ( P < .01). Muscle strength also was significantly reduced in patients with OI, ranging from -1.24 +/- 1.40 to -2.88 +/- 2.67 standard deviations lower compared with reference values. CONCLUSIONS: In patients with OI type I, no pulmonary or cardiac abnormalities at rest were found. The exercise tolerance and muscle strength were significantly reduced in patients with OI, which might account for their increased levels of fatigue during activities of daily living.