Studies using ultrasound.

BMC = Bone mineral content; BMD = Bone mineral density; BUA = Broadband ultrasound attenuation; CG = Control group; DAN = Dancers; DXA = Dual-energy x-ray absorptiometry; CG = Control group; GYM = Gymnasts; JUM = Jumpers; IGF-I = Insulin-like growth factor 1; M = Men; NTx = Cross-linked N-telopeptide of type I collagen; OC = Osteocalcin; QUS = Quantitative ultrasound; RUN = Runners; SWI = Swimmers; SWI1 = Post-menopausal swimmers for less than 5 years ; SWI2 = Post-menopausal swimmers for more than 5 years; SOC = Soccer; SOF = Softball; SOS = Speed of sound; SYS = Synchronized swimmers; W = Women; WPO = Water polo.