Bone properties and muscle strength of young haemophilia patients.

PURPOSE: To evaluate bone properties, muscle strength and the relationship between the two, in young (7.0-17.7 years) haemophilia patients (h) and healthy boys (c). SUBJECTS: Twenty-seven boys with severe haemophilia and 33 healthy boys, of similar age, body mass, height, (mean +/- sd for h and c, respectively: 11.2 +/- 3.2 vs. 11.4 +/- 2.9 years, 42.6 +/- 16.6 vs. 41.6 +/- 17.3 kg, 145 +/- 18 vs. 146 +/- 17 cm) and pubertal stage according to secondary sex characteristics, volunteered for the study. all subjects were physically inactive (as determined by questionnaire). METHODS: Subjects performed isokinetic elbow and knee extension and flexion tests at two angular velocities (biodex system ii dynamometer). Bone properties were evaluated by qualitative ultrasound (sunlight omnisense), at the distal radius and tibial mid-shaft. H subjects received prophylactic factor viii treatment within the 24 h preceding testing. No test was performed in the presence of haemorrhage. RESULTS: Muscle strength was consistently higher in c compared with h, especially in the lower limbs (e.g. knee extension: 1.80 +/- 0.44 vs 1.48 +/- 0.53 N x m x kg(-1) body mass, respectively, p = 0.01). No differences were observed in tibial or radial speed of sound between groups. Correlations between muscle strength and bone properties were observed only in the lower limbs and only in c (r = 0.37-0.48). CONCLUSION: Muscle strength, especially lower limbs' strength, was lower in haemophilia patients compared with a matched, similarly inactive population of healthy boys. Nevertheless, at this age range, this relative weakness is not associated with inferior bone properties.

Anaerobic power and muscle strength in young hemophilia patients.

PURPOSE: The purpose of this study was to evaluate muscle strength and anaerobic power in young boys with hemophilia compared with healthy boys. METHODS: Thirteen boys with severe hemophilia (H) (mean (+/- SD) age = 12.0 +/- 3.17 yr) and 16 control (C) boys (age = 11.9 +/- 2.8 yr) performed elbow and knee flexion and extension on the Biodex System II dynamometer at two angular velocities. They also performed a Wingate Anaerobic Test (WAnT) for the legs and for the arms. All H subjects received prophylactic factor VIII treatment in the 24 h pretesting, and no test was performed in the presence of hemorrhage. RESULTS: C were consistently stronger than H in all dynamic strength measures (e.g., elbow flexors: 0.47 +/- 0.15 vs 0.36 +/- 0.08 N x m x kg(-1) for C and H, respectively, P < 0.05). Anaerobic mean power was also higher in C compared with H in both upper and lower extremities (arms: 3.08 +/- 0.99 vs 2.22 +/- 0.46 W x kg(-1) for C and H, respectively; legs: 6.94 +/- 1.62 vs 5.54 +/- 1.03 W x kg(-1) for C and H, respectively, P < 0.05). Upper and lower extremity strength, as well as anaerobic power, increased with age in C but not in H. By using the Godin Leisure-Time Exercise Questionnaire, H were found to be much less active, especially in intense activities, compared with C. CONCLUSION: Children and adolescents with hemophilia are characterized by lower muscle strength and anaerobic power compared with age-matched controls. This may be related to their lower leisure-time activity.