title: Physical Activity and Bone: May the Force be with You.
abstract: Physical activity (PA) is thought to play an important role in preventing bone loss and osteoporosis in older people. However, the type of activity that is most effective in this regard remains unclear. Objectively measured PA using accelerometers is an accurate method for studying relationships between PA and bone and other outcomes. We recently used this approach in the Avon Longitudinal Study of Parents and Children (ALSPAC) to examine relationships between levels of vertical impacts associated with PA and hip bone mineral density (BMD). Interestingly, vertical impacts >4g, though rare, largely accounted for the relationship between habitual levels of PA and BMD in adolescents. However, in a subsequent pilot study where we used the same method to record PA levels in older people, no >4g impacts were observed. Therefore, to the extent that vertical impacts need to exceed a certain threshold in order to be bone protective, such a threshold is likely to be considerably lower in older people as compared with adolescents. Further studies aimed at identifying such a threshold in older people are planned, to provide a basis for selecting exercise regimes in older people which are most likely to be bone protective.
authors.affiliation: Musculoskeletal Research Unit, University of Bristol School of Clinical Sciences, Avon Orthopaedic Centre, Southmead Hospital , Bristol , UK.
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Tobias
authors.affiliation: Musculoskeletal Research Unit, University of Bristol School of Clinical Sciences, Avon Orthopaedic Centre, Southmead Hospital , Bristol , UK.
authors.forename: Virginia
authors.initials: V
authors.lastname: Gould
authors.affiliation: Musculoskeletal Research Unit, University of Bristol School of Clinical Sciences, Avon Orthopaedic Centre, Southmead Hospital , Bristol , UK.
authors.forename: Luke
authors.initials: L
authors.lastname: Brunton
authors.affiliation: Musculoskeletal Research Unit, University of Bristol School of Clinical Sciences, Avon Orthopaedic Centre, Southmead Hospital , Bristol , UK.
authors.forename: Kevin
authors.initials: K
authors.lastname: Deere
authors.affiliation: German Aerospace Center, Institute of Aerospace Medicine , Cologne , Germany.
authors.forename: Joern
authors.initials: J
authors.lastname: Rittweger
authors.affiliation: Atrium Medical Centre, AHORSE Foundation , Heerlen , Netherlands.
authors.forename: Matthijs
authors.initials: M
authors.lastname: Lipperts
authors.affiliation: Atrium Medical Centre, AHORSE Foundation , Heerlen , Netherlands.
authors.forename: Bernd
authors.initials: B
authors.lastname: Grimm
keywords: BMD; bone; exercise; impact loading; physical activity