title: Muscle-bone relationships in the lower leg of healthy pre-pubertal females and males.
abstract: Muscle-bone relationships in healthy pre-pubertal children were investigated using four muscle measures as predictors of tibial strength: 66% tibia cross-sectional muscle area (CSMA) by pQCT; leg lean mass (LLM) by DXA; and muscle power (Power) and force (Force) measured during a two-footed jump. Polar strength strain index (pSSI), a calculated surrogate for bone strength at the 20% distal tibia, was obtained on 105 (54 male) self-assessed pre-pubertal children. The amount of muscle (CSMA, LLM) may influence bone strength more than muscle strength (Power, Force) during periods of rapid growth. Correlations and multiple regression partial-R values from models controlling for age, sex, height and weight were obtained for each muscle predictor. CSMA, LLM, Power and Force were positively correlated with pSSI (R=0.84, 0.92, 0.85; 0.66, respectively, all p<0.01). Partial-R values were highest for LLM (partial-R=0.21), similar for CSMA and Power (0.14, 0.15, respectively) and lowest for Force (0.04) in predicting pSSI. Muscle predictors were associated with total and cortical area (R=0.59 to 0.90; p<0.01 for all), but not cortical vBMD at the 20% distal tibia site. These data support relationships between muscle predictors and bone parameters measured by pQCT in healthy pre-pubertal children.
authors.affiliation: Ethel Austin Martin Program in Human Nutrition, South Dakota State University, Bookings, SD 57007, USA, teresa.binkley@sdstate.edu
authors.forename: T L
authors.initials: TL
authors.lastname: Binkley
authors.forename: B L
authors.initials: BL
authors.lastname: Specker
mesh_terms: D015502:Absorptiometry, Photon; D019412:Anatomy, Cross-Sectional; D015519:Bone Density; D001842:Bone and Bones / Q000033:anatomy & histology / Q000378:metabolism / Q000502:physiology*; D002648:Child; D005260:Female; D006801:Humans; D007866:Leg / Q000000981:diagnostic imaging; D008297:Male; D008954:Models, Biological; D009068:Movement / Q000502:physiology; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000502:physiology*; D011627:Puberty; D013718:Tensile Strength; D013851:Thinness / Q000000981:diagnostic imaging; D013977:Tibia / Q000502:physiology