| Autor: |
Greene DA; Centre of Physical Activity Across the Lifespan, School of Exercise Science, Australian Catholic University (ACU National), Strathfield, NSW 2135, Australia. david.greene@acu.edu.au, Wiebe PN, Naughton GA |
| Jazyk: |
angličtina |
| Zdroj: |
Calcified tissue international [Calcif Tissue Int] 2009 Aug; Vol. 85 (2), pp. 94-103. Date of Electronic Publication: 2009 May 21. |
| DOI: |
10.1007/s00223-009-9253-7 |
| Abstrakt: |
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 cm(2)) and cross-sectional moment of inertia (cm(4)) 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. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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