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.

Abbreviations: ASK, Activity Scale for Kids, FFM, Fat-free mass, HR, Heart rate, PAL, Physical activity level