Swimming and peak bone mineral density: A systematic review and meta-analysis.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of observational cross-sectional/cohort studies
PubMed 28394711 · doi:10.1080/02640414.2017.1307440
What was done
A systematic review and random-effects meta-analysis evaluated the association between regular swimming and bone mineral density (BMD) at the whole body, femoral neck, and lumbar spine in young adults aged 18 to 30 years. Systematic searches were conducted in PubMed, SPORTDiscus, and the Cochrane Library through March 2016. Swimmers were compared with non-athletic controls (CG) and high-impact athletes (HIGH) across 14 included studies using Hedges' g effect sizes.
What was found
Swimmers showed similar BMD values to non-athletic controls: - Whole-body: g = -0.20 (P = 0.251) - Femoral neck: g = -0.05 (P = 0.818) - Lumbar spine: g = 0.18 (P = 0.492) Swimmers showed significantly lower BMD values compared to high-impact athletes: - Whole-body: g = -1.21 (P < 0.001) - Femoral neck: g = -1.51 (P < 0.001) - Lumbar spine: g = -0.84 (P = 0.017) Meta-regression showed that higher latitude was associated with smaller whole-body differences between swimmers and high-impact athletes (B = 0.10, P = 0.001), and age reduced femoral neck differences (B = 0.19, P = 0.020).
Why it matters
Because swimming is a non-weight-bearing sport, regular swimming does not enhance peak bone mass beyond sedentary baseline levels in young adults. Athletes exclusively swimming may require supplemental high-impact activity to optimize bone health.
Limits
The abstract does not report the total participant count, sex breakdown, swimming volume, or specific types of high-impact sports. The underlying studies are observational comparisons subject to unmeasured confounding such as dietary intake and genetic factors.
Cited by
- supports Non-weight-bearing exercises such as cycling, swimming, and elliptical training do not produce substantial osteogenic effects on bone mineral density compared to weight-bearing exercise.