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| Effect
of 8-month vertical whole body vibration on bone, muscle performance,
and body balance: a randomized controlled study. |
Torvinen
S, Kannus P, Sievänen H, Järvinen TA, Pasanen M, Kontulainen
S, Nenonen A, Järvinen TL, Paakkala T, Järvinen M, Vuori I.
Bone Research Group,
UKK Institute, Tampere, Finland.
Recent animal studies
have given evidence that vibration loading may be an efficient and safe
way to improve mass and mechanical competence of bone, thus providing
great potential for preventing and treating osteoporosis. Randomized controlled
trials on the safety and efficacy of the vibration on human skeleton are,
however, lacking. This randomized controlled intervention trial was designed
to assess the effects of an 8-month whole body vibration intervention
on bone, muscular performance, and body balance in young and healthy adults.
Fifty-six volunteers (21 men and 35 women; age, 19-38 years) were randomly
assigned to the vibration group or control group. The vibration intervention
consisted of an 8-month whole body vibration (4 min/day, 3-5 times per
week). During the 4-minute vibration program, the platform oscillated
in an ascending order from 25 to 45 Hz, corresponding to estimated maximum
vertical accelerations from 2 g to 8 g. Mass, structure, and estimated
strength of bone at the distal tibia and tibial shaft were assessed by
peripheral quantitative computed tomography (pQCT) at baseline and at
8 months. Bone mineral content was measured at the lumbar spine, femoral
neck, trochanter, calcaneus, and distal radius using DXA at baseline and
after the 8-month intervention. Serum markers of bone turnover were determined
at baseline and 3, 6, and 8 months. Five performance tests (vertical jump,
isometric extension strength of the lower extremities, grip strength,
shuttle run, and postural sway) were performed at baseline and after the
8-month intervention. The 8-month vibration intervention succeeded well
and was safe to perform but had no effect on mass, structure, or estimated
strength of bone at any skeletal site. Serum markers of bone turnover
did not change during the vibration intervention. However, at 8 months,
a 7.8% net benefit in the vertical jump height was observed in the vibration
group (95% CI, 2.8-13.1%; p = 0.003). On the other performance and balance
tests, the vibration intervention had no effect. In conclusion, the studied
whole body vibration program had no effect on bones of young, healthy
adults, but instead, increased vertical jump height. Future human studies
are needed before clinical recommendations for vibration exercise. |

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