Anaerobic power and muscle strength in young hemophilia patients.

Abstract

The purpose of this study was to evaluate muscle strength and anaerobic power in young boys with hemophilia compared with healthy boys. 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. 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. 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.