Influence of drop-landing exercises on bone geometry and biomechanical properties in prepubertal girls: A randomized controlled study
Greene, David A. Wiebe, Peter N. Naughton, Geraldine A.
Greene, David A.
Wiebe, Peter N.
Naughton, Geraldine A.
Abstract
We conducted a 28-week school-based exercise trial of single-leg drop-landing exercise with 42 girls (Tanner stage 1, 6–10 years old) randomly assigned to control (C), low-drop (LD), or high-drop (HD) exercise groups. The LD and HD groups performed single-leg drop-landings (three sessions/week and 50 landings/session) from 14 and 28 cm, respectively, using the nondominant leg. Single-leg peak ground-reaction impact forces in a subsample ranged between 2.5 and 4.4 times body weight. Dependent variables were bone geometry and biomechanical properties using magnetic resonance imaging. No differences (P > 0.05) were found among groups at baseline for age, stature, lean tissue mass (DXA - Lunar 3.6-DPX), leisure-time physical activity, average daily calcium intake, or measures of knee extensor or flexor torque. A series of ANOVA and ANCOVA tests showed no within- or between-group differences from baseline to posttraining. Group comparisons assessing magnitude of change in side-to-side differences in geometry (area cm2) and cross-sectional moment of inertia (cm4) at proximal, mid, and distal sites revealed negligible effect sizes. Our findings suggest that strictly controlled unimodal, unidirectional single-leg drop-landing exercises involving low to moderate peak ground-reaction impact forces do not influence geometrical or biomechanical measures in the developing prepubertal female skeleton.
Keywords
Date
2009
Type
Journal article
Journal
Calcified Tissue International
Book
Volume
85
Issue
2
Page Range
94-103
Article Number
ACU Department
School of Behavioural and Health Sciences
Faculty of Health Sciences
Faculty of Health Sciences