Exercise for optimising peak bone mass in women

Abstract

Physical activity is one of the major non-pharmacological methods for increasing and maintaining bone mineral density (BMD) and geometry. As such, it has an important role in maintaining peak bone mass and strength, thus reducing the risk of future osteoporotic fracture. However, not all exercise is effective, so a prescription in terms of optimal type, intensity, frequency and duration is required. Studies using animal models suggest that loading that is high in magnitude, rapidly applied and novel is most effective, whilst duration is less important beyond a threshold number of cycles. In human subjects cross-sectional studies comparing different athletic populations suggest that those who participate in high-or odd-impact sports have higher BMD; whilst impact exercise, strength training and brief high-impact-jump training interventions increase BMD in premenopausal women. In order to further elucidate exercise recommendations to optimise bone health in this population, the usefulness of brief high-impact unilateral exercises has been evaluated. Brief hopping exercises were shown to be feasible for sedentary premenopausal women, producing ground-reaction forces as high as those from jumping. Regularly performing these hopping exercises over 6 months was found to increase femoral-neck BMD of the trained leg relative to the control leg. Unilateral high-impact exercise may therefore improve bone strength of the trained limb and provide a useful model for comparing exercise prescriptions to help define the most efficient and effective exercise recommendations for the bone health of premenopausal women. Exercise: Bone mineral density: Premenopausal womenOsteoporosis is a condition of skeletal fragility whereby depleted bone mass and compromised bone structure weaken bone to such an extent that fractures occur from minimal trauma. The disease is a major public health problem with great social and economic importance. One in five men and one in two women in the UK > 50 years of age will suffer an osteoporosis-related fracture in their lifetime (1) and the annual cost for all fractures is £1 . 5 · 10 9(2) .Two mechanisms that principally determine adult bone health are peak bone mineral density (BMD) at skeletal maturity and the rate of bone loss with advancing age; thus, maximising premenopausal BMD is a critical strategy for the prevention of osteoporosis and resultant fractures later in life. A substantial body of literature has established that participating in regular physical activity can positively improve bone mineral status (3,4) . The advantage of exercise over methods such as dietary intervention is that it increases the skeleton's resistance to fracture by improving and maintaining both BMD and neuromuscular competency, thus reducing both skeletal fragility and predisposition to falls (4) .Exercise recommendations for cardiovascular fitness have already been precisely defined (5) , but it is unlikely that the same exercise prescription applies to cardiovascular health and skeletal health, and to both pre-a...

Long-term voluntary exercise of male mice induces more beneficial effects on cancellous and cortical bone than on the collagenous matrix

“…Bone mass in aging adults may decrease more rapidly with unfit physical conditions or lifestyle (Karlsson, 2004). Lifelong physical exercise can reduce the rate of bone mineral decline and prevent or delay the onset of osteoporosis (Bailey and Brooke-Wavell, 2008).…”

Bone Mineral Density in Female Professional Athletes Involved in Weight Bearing and Non-Weight Bearing Exercises

“…Animal studies have considered loading exercises that are high in magnitude, rapidly applied, dynamic and novel as greater osteogenic stimuli, adding that the duration of the workout is less important once a certain threshold level has been reached [13,30,31]. Furthermore, it has been suggested that the distribution of strain may be more important than its magnitude, as unusual patterns of strain can stimulate an osteogenic response at a lower minimum effective strain (MES) [31][32][33]. Mechanical loading, therefore, is more osteogenic when short rest intervals are inserted between cycles in order to avoid the saturation of the bone's adaptive response to mechanical load [34,35].…”

“…While high-impact sports are associated with a greater BMD, there is no difference between bone properties of swimmers, who do not experience any loading, compared to the sedentary controls [20,31]. Some studies have also shown the lower prevalence of osteopenia and osteoporosis among those involved in brisk walking compared to those involved in Taijiquan and swimming [5,42].…”

“…Considering the concept of strain distribution, it could be concluded that sports such as football, squash, volleyball, gymnastics and rowing, which stress bone in a variety of directions, are associated with a higher BMD than sports consisting of only one direction of movement such as running and swimming [31,38]. As a result, individuals should be recommended to perform exercises that provide adequate skeletal loading so that they would benefit the most from their time and effort dedicated to physical activity.…”

Evaluation of commercial activity monitors for quantification of high- and low-impact exercise

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Physical activity incorporating impact loading increases bone mineral density, so objective quantification of such activity is needed to quantify adherence to interventions (1) . Accelerometry is a practical method for monitoring daily physical activity that incorporates walking and running (2) but the most-widely-used devices have not been evaluated for their ability to quantify other types of exercise.

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