Abstract
Objective To assess the effect of range-of-motion exercise program on bone mineralization and
somatic growth of very low birth weight (VLBW) infants.
Study Design A total of 36 VLBW infants were randomized into 18 VLBW infants receiving range-of-motion
exercise and 18 VLBW control infants receiving tactile stimulation for 4 weeks. Laboratory
investigations were performed at baseline and postexercise and included serum calcium,
serum phosphorus (s.PO4), magnesium, alkaline phosphatase (ALP), urinary calcium/phosphate ratio, and serum
carboxy-terminal cross-linked telopeptide of type 1 collagen (CTX). Dual-energy X-ray
absorptiometry was performed at the end of the exercise protocol to measure bone mineral
content, bone mineral density (BMD), bone area, lean mass, and fat mass.
Results The weight and the rate of weight gain were significantly higher (p < 0.001) in the exercise group compared with controls postexercise. Also, higher
s.PO4, lower ALP, and lower urinary calcium/phosphate ratio were observed postexercise
in the exercise group (p = 0.001, p = 0.005, and p = 0.04, respectively), whereas serum CTX showed no difference between the two groups
(p = 0.254). Postexercise BMD significantly improved in the exercise group (p < 0.001) compared with controls.
Conclusion Although the sample size was small, we may be able to suggest favorable effects of
range-of-motion exercise versus tactile stimulation on bone metabolism, BMD, and short-term
growth in VLBW infants.
Keywords
metabolic bone disease - physical activity - bone mineral density - preterm infant
