1.
The Effect of Swimming During Childhood and Adolescence on Bone Mineral Density: A Systematic Review and Meta-Analysis.
Gomez-Bruton, A, Montero-Marín, J, González-Agüero, A, García-Campayo, J, Moreno, LA, Casajús, JA, Vicente-Rodríguez, G
Sports medicine (Auckland, N.Z.). 2016;(3):365-79
Abstract
BACKGROUND The effects of swimming on bone mineral density (BMD) have been studied by several researchers, with inconsistent results. AIM: This meta-analysis aims to determine whether systematic swimming training may influence BMD during childhood and adolescence. METHODS A systematic search was performed in PubMed, SPORTDiscus and ClinicalTrials.gov from the earliest possible year to March 2015, with data extraction and quality assessment performed independently by two researchers following the PRISMA methodology. Swimmers were compared to sedentary controls and to athletes performing highly osteogenic sports. Therefore, a total of two meta-analyses were developed. RESULTS Fourteen studies met the inclusion criteria and were included in the meta-analyses. Swimmers presented similar BMD values to sedentary controls and lower than other high-impact athletes. Femoral neck and lumbar spine BMD differences between swimmers and sedentary controls and between swimmers and athletes practicing osteogenic sports appeared to increase with age and favored the non-swimming groups. There were no differences by sex. CONCLUSION While swimming is associated with several health benefits, it does not appear to be an effective sport for improving BMD. Swimmers might be in need of additional osteogenic exercises for increasing BMD values.
2.
Variability in measurement of swimming forces: a meta-analysis of passive and active drag.
Havriluk, R
Research quarterly for exercise and sport. 2007;(2):32-9
Abstract
An analysis was conducted to identify sources of true and error variance in measuring swimming drag force to draw valid conclusions about performance factor effects. Passive drag studies were grouped according to methodological differences: tow line in pool, tow line in flume, and carriage in tow tank. Active drag studies were grouped according to the theoretical basis: added and/or subtracted drag (AAS), added drag with equal power assumption (AAE), and no added drag (ANA). Data from 36 studies were examined using frequency distributions and meta-analytic procedures. It was concluded that two active methods (AAE and ANA) had sources of systematic error and that one active method (AAS) measured an effect that was different from that measured by passive methods. Consistency in drag coefficient (Cd) values across all three passive methods made it possible to determine the effects of performance factors.