20 (95 % CI 0.03, 0.97). The main limitation of this analysis was the measurement of 25OHD at the time of presentation KU-57788 rather than at the initiation

of and during bisphosphonate therapy. Nevertheless, our study indicated that vitamin D status was significantly better in cases vs controls at the time of fracture, suggesting that vitamin D status might be a less important factor than previously thought in the development of bisphosphonate-associated atypical femoral fractures. References 1. Shane E, Burr D, Ebeling PR, Abrahamsen B, Adler RA, Brown TD, Cheung AM, Cosman F, Curtis JR, Dell R, Dempster D, Einhorn TA, Genant HK, Geusens P, Klaushofer K, Koval K, Lane JM, McKiernan F, McKinney R, Ng A, Nieves p38 MAPK inhibitor review J, O’Keefe R, Papapoulos S, Sen HT, van der Meulen MC, Weinstein RS, Whyte M (2010) Atypical subtrochanteric and diaphyseal femoral fractures: report of a task force of the American Society for Bone and Mineral Research. J Bone Miner Res 25:2267–2294PubMedCrossRef 2. Girgis CM, Sher D, Seibel MJ (2010) Atypical femoral fractures and bisphosphonate use. N Engl J Med 362:1848–1849PubMedCrossRef 3. Goh SK, Yang KY, Koh JS, Wong MK, Chua SY, Chua DT, Howe TS (2007) Subtrochanteric insufficiency fractures in patients on alendronate therapy: a caution. J Bone Joint Surg Br 89:349–353PubMedCrossRef”
“Introduction

Even though variance in bone mass is mostly genetically determined [1], it is well known that bones adapt to a specific mechanical loading to which they are habitually exposed [2]. Physical exercise has been suggested as an intervention strategy to promote optimal bone gain and bone strength during youth [3] and to reduce the rate of bone loss later in life [4].

Weight-bearing loading has also been found to be more effective than nonweight-bearing activities such as swimming and bicycling in the enhancement of bone mass [5–9]. Bone tissue responds to dynamic rather than static loading [10], and several studies have suggested that the type of physical activity and the O-methylated flavonoid accompanying dynamic activity are of particular importance [11–15]. The maximum effect is believed to be achieved by weight-bearing physical activity including jumping actions, explosive actions (such as turning and sprinting), and fairly few repetitions rather than endurance or nonweight-bearing activities [5, 8, 16–18]. Peak bone mass is believed to be achieved before the end of the third decade in life, GDC-0994 chemical structure depending on bone site, and low peak bone mass has been considered as a risk factor for developing osteoporosis later in life [1, 19, 20]. Higher peak bone mass attained through weight-bearing exercise may also contribute to a larger bone size and higher bone strength in older men [21, 22]. Both skeletal muscle mass and lean body mass are correlated with bone mineral density (BMD) at different skeletal sites [23, 24].