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Assisted exercise and bone strength in preterm infants

I Litmanovitz1, T Dolfin, S Arnon

  • 1Department of Neonatology, Pediatrics, Meir Medical Center, Kfar-Saba, Sackler School of Medicine, Tel-Aviv University, 59 Tchernichovsky Street, Kfar-Saba 44281, Israel.

Calcified Tissue International
|December 14, 2006
PubMed

Insights

Eight weeks of passive range-of-motion exercise helps maintain bone strength in very low birth weight (VLBW) preterm infants. This intervention may reduce the risk of osteopenia, with benefits observed early in the treatment period.

Area of Science:

  • Neonatal Medicine
  • Pediatric Bone Health
  • Developmental Pediatrics

Background:

  • Very low birth weight (VLBW) preterm infants are at high risk for osteopenia due to limited physical activity and altered bone metabolism.
  • Previous studies suggest short-term (4 weeks) passive range-of-motion (PROM) exercise benefits bone development in VLBW infants.
  • The optimal duration of exercise for improving bone health in this vulnerable population remains undetermined.

Purpose of the Study:

  • To investigate the effect of 8 weeks of daily assisted passive range-of-motion exercise on bone strength and metabolism in VLBW preterm infants.
  • To determine if prolonged exercise intervention can attenuate the typical postnatal decline in bone mineral status.
  • To assess changes in biochemical markers of bone turnover alongside quantitative ultrasound measurements.

Main Methods:

  • A randomized controlled trial involving 16 VLBW preterm infants (birth weight 1,009 ± 55 g, gestational age 27.3 ± 0.3 weeks).
  • Infants were assigned to either an 8-week daily assisted PROM exercise group or a control group.
  • Bone strength was assessed weekly using tibial bone speed of sound (SOS) via quantitative ultrasound; bone turnover markers were measured at baseline and 8 weeks.

Main Results:

  • The control group exhibited a significant postnatal decrease in bone SOS (-108.1 m/s, P < 0.0001).
  • In contrast, bone SOS remained stable in the exercise group (11.3 m/s), indicating preserved bone strength.
  • The primary beneficial effects of exercise on bone strength were evident within the first 4 weeks of the intervention; no significant differences in bone turnover markers were observed between groups.

Conclusions:

  • A significant postnatal decline in bone strength (measured by SOS) occurs in VLBW preterm infants.
  • Eight weeks of assisted PROM exercise effectively attenuates this decline, preserving bone strength.
  • This exercise intervention shows potential in reducing the risk of osteopenia in premature infants, with early benefits observed.

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