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.