Muscle cross sectional area and grip torque contraction types are similarly related to pQCT derived bone strength indices in the radii of older healthy adults.
OBJECTIVE
We sought to identify the variance in radius bone strength indices explained by forearm muscle cross sectional area (MCSA) and isometric (ISO), concentric (CON), or eccentric (ECC) grip torque in healthy men and postmenopausal women when gender and body size were controlled for. Additionally we assessed variance in various grip contractions explained by MCSA.


METHODS
pQCT estimated bone strength of the radius and forearm MCSA were measured from 45 healthy adults (59.4-/+7.2 yrs). Isokinetic dynamometry was used to assess peak grip torque. Regressions were adjusted for gender and radius length.


RESULTS
Peak grip torques were not independent predictors (p>0.05) of distal radius bone strength in compression (bone strength index; BSI(c)) when gender was included in the prediction model. Gender was not a contributor to any model that included MCSA (p>0.05). At the diaphysis all torque measures, MCSA, gender, and length, significantly contributed to predict similar portions (79-80%) of the stress strain index (SSI(p); strength in torsion). MCSA accounted for 68-76% of variance in grip torque (p<0.05).


CONCLUSIONS
When estimating radius bone strength, forearm MCSA is a comparable predictor to CON, ISO, and ECC grip torques and is also a good surrogate of these contraction types.
Frank
A W
AW
College of Kinesiology, University of Saskatchewan, Canada.
Lorbergs
A L
AL
Chilibeck
P D
PD
Farthing
J P
JP
Kontulainen
S A
SA
D000368:Aged; D015519:Bone Density / Q000502:physiology*; D001842:Bone and Bones / Q000502:physiology*; D005260:Female; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D053581:Muscle Strength Dynamometer; D018482:Muscle, Skeletal / Q000033:anatomy & histology* / Q000502:physiology*; D012044:Regression Analysis; D019415:Torque