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| Low-frequency
vibratory exercise reduces the risk of bone fracture more than walking:
a randomized controlled trial. |
Gusi
N, Raimundo A, Leal A.
Faculty of Sports
Sciences, University of Extremadura, Cáceres, Spain. ngusi@unex.es
BACKGROUND: Whole-body
vibration (WBV) is a new type of exercise that has been increasingly tested
for the ability to prevent bone fractures and osteoporosis in frail people.
There are two currently marketed vibrating plates: a) the whole plate
oscillates up and down; b) reciprocating vertical displacements on the
left and right side of a fulcrum, increasing the lateral accelerations.
A few studies have shown recently the effectiveness of the up-and-down
plate for increasing Bone Mineral Density (BMD) and balance; but the effectiveness
of the reciprocating plate technique remains mainly unknown. The aim was
to compare the effects of WBV using a reciprocating platform at frequencies
lower than 20 Hz and a walking-based exercise programme on BMD and balance
in post-menopausal women. METHODS: Twenty-eight physically untrained post-menopausal
women were assigned at random to a WBV group or a Walking group. Both
experimental programmes consisted of 3 sessions per week for 8 months.
Each vibratory session included 6 bouts of 1 min (12.6 Hz in frequency
and 3 cm in amplitude with 60 degrees of knee flexion) with 1 min rest
between bouts. Each walking session was 55 minutes of walking and 5 minutes
of stretching. Hip and lumbar BMD (g.cm-2) were measured using dual-energy
X-ray absorptiometry and balance was assessed by the blind flamingo test.
ANOVA for repeated measurements was adjusted by baseline data, weight
and age. RESULTS: After 8 months, BMD at the femoral neck in the WBV group
was increased by 4.3% (P = 0.011) compared to the Walking group. In contrast,
the BMD at the lumbar spine was unaltered in both groups. Balance was
improved in the WBV group (29%) but not in the Walking group. CONCLUSION:
The 8-month course of vibratory exercise using a reciprocating plate is
feasible and is more effective than walking to improve two major determinants
of bone fractures: hip BMD and balance. |

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