Girls' Bones May Break More Easily than Boys' Following Heavy Exercise
Results of a study into the way adolescent bones respond to physical activity are revealed at the 2012 ECTS Annual Congress, Stockholm, Sweden, 19-23 May
May 23, 2012, Stockholm, Sweden. Press Dispensary. Traditional measures of physical activity have mainly focused on energy expenditure, of which the latter is related to obesity but may be less relevant in terms of understanding how exercise affects the skeleton.
Recently, an investigation of male and female adolescents examined the relationship between the level of activity, as measured using a new accelerometer device which can differentiate activity according to the level of impact, and size and density of the tibial bone in the lower leg. The study found that the circumference of the tibia is greater in those undergoing more high impact activity. Interestingly, this association was stronger in boys, and in those with greater fat mass, which may help to explain why female sex and low body weight are risk factors for osteoporotic fractures in later life.
In a study of 675 participants (403 girls and 272 boys with a mean age of 17.7 years) from the Avon Longitudinal Study of Parents and Children (ALSPAC) based in the Southwest UK, primarily funded by the Wellcome Trust, the aim was to determine the influence of factors such as gender and fat mass on the relationship between physical activity and bone. The adolescents had a bone scan of their tibia using a low radiation device, and subsequently wore an accelerometer for seven days which measured their level of physical activity according to level of impact.
Having adjusted for differences in age, height, fat mass and lean mass, it was found that increased high impact activity (equivalent to impacts related to running faster than approximately 10km/hour) was associated with a larger tibial circumference in the boys whereas a similar relationship was not seen in the girls. For example, in boys, an eight-fold increase in the amount of high impact activity was associated with a 1.0mm greater circumference. In further analyses that split participants into groups defined by their fat mass, the relationship between high impact activity and circumference was greatest in those with a higher fat mass. Furthermore, there was now evidence of a positive association between high impact activity and tibial circumference in girls, provided analyses were restricted to those with the highest fat mass.
Professor Jon Tobias of the School of Clinical Sciences, University of Bristol, says:
"After undergoing strenuous exercise, in girls and those with low body weight, the skeleton seems to respond less well in terms of increasing its size as reflected by circumference. Although we saw other benefits, since bone expansion has a particularly strong influence on its overall strength, these observations may help to explain why women and those of low body weight appear to be at higher risk of developing osteoporotic fractures in later life."
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Notes for editors
Webcasts and a photo gallery of the congress are available on the ECTS website:-
Photo Gallery: http://www.ectscongress.org/2012/gallery/
About the study
The study – conducted with the help of Newtest accelerometers from Netwest Oy, Finland - was headed by K. Deere, A. Sayers and J. Tobias of the School of Clinical Sciences, University of Bristol, UK, and J. Rittweger of Division of Space Physiology, Institute of Aerospace Medicine, Cologne, Germany.
About the Congress
Taking place in Stockholm on 19-23 May, 2012, the 39th ECTS Annual Congress 2012 is Europe's key annual bone science event. The programme includes: symposium workshops covering bone biology and clinical research; results of the latest scientific research; clinical update sessions and a session dedicated to new investigators in the field.
About the ECTS
The European Calcified Tissue Society (ECTS) is the major organisation in Europe for researchers and clinicians working in the field of calcified tissues and related fields. ECTS acts as a forum for the dissemination of high quality research through its annual meeting, the European Symposium on Calcified Tissues, and through training courses and workshops.
Calcified tissues are central to a healthy skeleton and to bone disorders - such as osteoporosis, back pain and fractures - that make life a misery for countless people. Children can inherit some forms of bone diseases causing bone pain, shortness and deformed limbs.
ECTS 2013, celebrating the society's 50th year, will be held in Lisbon, Portugal, on 18-21 May 2013
For further information, please contact:
Roberta Mugnai, ECTS executive director
European Calcified Tissue Society (ECTS)
Tel: + 32 476 520 716
Conference site: www.ectscongress.org/2012