Relationship of muscle function to auxology in preterm born children at the age of seven years

Background/aims: To characterize the relationship between muscle function and auxology in preterm born children.

Methods: Forty-five preterm born children (birth weight < or =1,500 g with mean +/- SD: 1,069 +/- 281 g; median of gestational age: 29 weeks; 50% multiple births) were analyzed for auxological parameters (weight, height) and muscle function at the age of 7 years. Maximal isometric grip force (MIGF) and ground reaction forces of goal-directed counter-movement jumping were measured using the Preston dynamometer and the Leonardo force plate. MIGF, peak jump force (PJF), peak jump power (PJP) and the maximal velocity of take-off (V(max)) were analyzed for their relationship to perinatal risk factors and actual auxological parameters.

Results: With reference to age, weight-standard deviation score (SDS) and height-SDS were lower than in the reference population. With reference to height, MIGF-SDS and PJP-SDS were lower than in reference individuals. Children with intraventricular hemorrhage (IVH) had lower PJP-SDS and V(max) than children without IVH. PJP-SDS was lower than PJF-SDS in children with IVH.

Conclusion: Analyses showed a discrepancy between maximal force and power due to a decline of V(max) in children with IVH.