Assisted Physical Exercise for Improving Bone Strength in Preterm Infants Less than 35 Weeks Gestation: A Randomized Controlled Trial

Abstract

Objective: To compare the efficacy of daily assisted physical exercise (starting from one week of postnatal age) on bone strength at 40 weeks of post menstrual age to no intervention in infants born between 27 and 34 weeks of gestation.

Design: Open-label randomized controlled trial.

Setting: Tertiary-care teaching hospital in northern India from 16 May, 2013 to 21 November, 2013.

Participants: 50 preterm neonates randomized to Exercise group (n=26) or Control group (n=24).

Intervention: Neonates in Exercise group underwent one session of physical exercise daily from one week of age, which included range-of-motion exercises with gentle compression, flexion and extension of all the extremities with movements at each joint done five times, for a total of 10-15 min. Infants in Control group underwent routine care and were not subjected to any massage or exercise.

Main outcome measures: Primary: Bone speed of sound of left tibia measured by quantitative ultrasound at 40 weeks post menstrual age. Secondary: Anthropometry (weight length and head circumference) and biochemical parameters (calcium, phosphorus, alkaline phosphatase) at 40 weeks post menstrual age.

Results: The tibial bone speed of sound was comparable between the two groups [2858 (142) m/s vs. 2791 (122) m/s; mean difference 67.6 m/s; 95% CI - 11 to 146 m/s; P=0.38]. There was no difference in anthropometry or biochemical parameters.

Conclusions: Daily assisted physical exercise does not affect the bone strength, anthropometry or biochemical parameters in preterm (27 to 34 weeks) infants.