Physical activity programs may increase bone mineral density and weight gain in preterm infantsPhysical Activity Programs May Improve Bone Growth in Preterm Infants

Rationale Lack of physical stimulation may contribute to metabolic bone disease of preterm infants, resulting in poor bone mineralisation and growth. Physical activity programmes combined with adequate nutrition might help to promote bone mineralisation and growth. Objectives The primary objective was to assess whether physical activity programmes in preterm infants improve bone mineralisation and growth and reduce the risk of fractures. The secondary objectives included assessment of other potential benefits in terms of complications of preterm birth, length of hospital stay, skeletal deformities, neurodevelopmental outcomes and adverse events. Search methods We searched CENTRAL, MEDLINE, Embase and trial registries in October 2025. We checked the reference lists of included studies and systematic reviews where the subject matter related to the intervention or population examined in this review. Eligibility criteria We included randomised controlled trials (RCTs) and quasi‐RCTs of preterm infants born at less than 37 weeks' gestational age. We compared physical activity programmes (extension and flexion, range‐of‐motion exercises) with no organised physical activity programmes. Outcomes Our outcomes of interest were bone mineral content and density measured by absorptiometric x‐ray techniques at completion of the physical activity programme and at 12 to 24 months' corrected age, fractures at completion of the physical activity programme, body weight gain (g/kg/day) and body length gain (cm/week) during the study period. Risk of bias We used the Cochrane risk of bias tool (RoB 1). Synthesis methods We synthesised results for each outcome using fixed‐effect meta‐analysis, where possible. We expressed our results using the mean difference (MD), standardised mean difference (SMD), risk ratio (RR) and risk difference (RD) with 95% confidence intervals (CIs). We used GRADE to assess the certainty of evidence for each outcome. Included studies We identified five new RCTs for this update. In total, we included 15 RCTs enrolling 434 preterm infants (gestational age 26 to 34 weeks) in this review. All RCTs were small (N = 16 to 50), single‐centre studies. The trials were similar in design, although they slightly differed in the physical activity protocol. They evaluated whether daily physical activity, varying in duration from three and a half weeks to eight weeks during initial hospitalisation, compared to routine care or tactile stimulation, promoted bone mineralisation and growth. Postnatal age at the start of the physical activity programme varied between less than three days and up to four weeks of age. Methodological quality and reporting of included trials were variable. Synthesis of results We downgraded the certainty of the evidence to low or very low due to risk of bias, inconsistency and imprecision, mainly due to unclear or high risk of bias, substantial heterogeneity, wide confidence intervals or small sample size. Bone mineralisation Physical activity programmes in preterm infants, compared to no standardised programmes, may increase whole‐body bone mineral density (g/cm2) (MD 0.11, 95% CI 0.07 to 0.15; I² = 0%; 2 studies, 65 participants; low‐certainty evidence). The evidence is very uncertain about the effect of physical activity on the increase of whole‐body mineral content (g) during the study period (MD 5.58, 95% CI −0.88 to 12.04; I² = 95%; 2 studies, 65 participants; very low‐certainty evidence). No usable evidence was available for bone mineral content at 12 to 24 months' corrected age. Fractures The evidence is very uncertain about the effect of physical activity on the risk of fractures (RR 0.33, 95% CI 0.01 to 7.68; I² not applicable; 3 studies, 102 participants; very low‐certainty evidence; two studies have zero events in both arms). Growth during the study period Physical activity may increase gain in body weight (g/kg/day) during the study period (MD 2.98, 95% CI 2.31 to 3.65; I² = 83%; 14 studies, 418 participants; low‐certainty evidence), but may result in little to no increase in body length gain (cm/week) (MD 0.05, 95% CI −0.02 to 0.13; I² = 66%; 11 studies, 355 participants; low‐certainty evidence). Authors' conclusions There is low to very low‐certainty evidence on the effect of physical activity programmes, compared to no standardised programmes, on bone mineralisation and growth in preterm infants. Physical activity programmes may increase whole‑body bone mineral density and body weight gain, and may have little to no effect on body length gain compared to no standardised programmes. It is very uncertain whether physical activity programmes have any effect on whole‑body mineral content or the risk of fractures. No adequate data are available on bone mineralisation at 12 to 24 months' corrected age. Given the low to very low‐certainty evidence for all outcomes, further large, well‐designed RCTs are needed to assess the effects of physical activity programmes on bone mineralisation and growth in preterm infants. Funding This Cochrane review had no dedicated funding. Registration Protocol (2005) DOI 10.1002/14651858.CD005387Original review (2007) DOI 10.1002/14651858.CD005387.pub2Review update (2014) DOI 10.1002/14651858.CD005387.pub3 Plain language summary Physical activity programmes for improving bone mineralisation (bone development) and growth in preterm infants Key messages In preterm infants, physical activity programmes may provide a small benefit for bone development and body weight gain over the short term. Physical activity programmes may have little to no effect on body length gain. We do not know if physical activity programmes affect the risk of fractures (broken bones), and we don't have enough information to assess long‐term benefits and harm. What is poor bone development and growth in preterm infants? Babies born too early (born before 37 weeks of pregnancy) are often cared for in a way that minimises physical activity to reduce stress and stress‐related complications. However, lack of physical activity might lead to poor bone development and growth, particularly in very low birth weight infants (meaning babies born weighing less than 1500 g). This may have long‐term consequences, as seen in bedridden children and adults. What are physical activity programmes? Physical activity programmes are daily exercise where all joints in the arms and legs are gently moved and pressed for a few minutes each day over several weeks. What is bone mineralisation? Bone mineralisation is the process in which minerals, mainly calcium and phosphorus, are added to newly formed bone tissue, making the bone hard and strong. What did we want to find out? We wanted to find out whether physical activity programmes given during the initial hospital stay help preterm infants to develop stronger bones and grow better. We planned to assess this at the end of the programme and 12 to 24 months after the expected date of delivery. We also wished to examine whether these programmes affect the risk of fractures (broken bones). What did we do? We searched for studies that compared physical activity programmes with no organised programmes in preterm infants. What did we find? We included 15 small studies, with 434 infants, in our review. We found that preterm infants who received a daily physical activity programme for several weeks might have slightly better bone mineralisation and gain in body weight when assessed at completion of the programme, but we are uncertain about the results. We don't know whether physical activity programmes have a long‐term effect on bone mineral content, because none of our included studies gave information on this outcome. We found no evidence that the physical activity programmes reduced or increased body length. We found very uncertain evidence regarding their effect on the frequency of fractures. What are the limitations of the evidence? Our confidence in the results is low to very low because many of the included studies were small or had limitations in their methods. When several studies were combined for specific outcomes, the results were often imprecise and inconsistent. Because of this, we are uncertain whether physical activity programmes have meaningful effects on bone mineralisation, weight gain, body length gain or the risk of a fracture. The evidence only covers outcomes measured during the initial hospital stay, and we do not have evidence about longer‐term effects. How up to date is this evidence? This review updates our previous review from 2014. The evidence is up to date as of October 2025. Visual summary Unlock the full review Close Save citation to: RefWorks SciWheel