Effects of intensive whole body vibration training on muscle strength and balance in adults with chronic stroke: A randomized controlled pilot study.

OBJECTIVES:
To investigate the effects of a 6-week whole body vibration (WBV) training program in patients with chronic stroke.
DESIGN:
Randomized controlled pilot trial with 6 weeks follow-up.
SETTING:
University hospital.
PARTICIPANTS:
Fifteen adults with chronic stroke were randomly assigned to an intervention (n=7) or a control group (n=8).
INTERVENTIONS:
Supervised intensive WBV training. The vibration group performed a variety of static and dynamic squat exercises on a vibration platform with vibration amplitudes of 1, 7 and 2, 5 mm and frequencies of 35 and 40 Hz. The vibration lasted 30 to 60 seconds, with 5 to 17 repetitions per exercise 3 times weekly for 6 weeks. The participants of the control group continued their usual activities and were not involved in any additional training program.
MAIN OUTCOME MEASURES:
The primary outcome variable was the isometric and isokinetic muscle strength of quadriceps (isokinetic dynamometer). Additionally, hamstrings muscle strength, static and dynamic postural control (dynamic posturography) and muscle spasticity (Ashworth scale) were assessed.
RESULTS:
Compliance with the vibration intervention was excellent and the participants completed all 18 training sessions. Both vibration frequencies of 35Hz and 40Hz were well-tolerated by the patients and no adverse effects due to the vibration were noted. Overall, the current outcomes show that the effect of intensive whole body vibration intervention resulted in significant between-group differences in favor of the vibration group only in isometric knee extension strength (knee angle 60°) (P=.022) after 6 weeks of intervention and in isokinetic knee extension strength (velocity of 240°/s) after a 6 weeks follow-up period (P=.005), both for the paretic leg. Postural control improved after 6 weeks of vibration in the intervention group when the patients had normal vision and a sway referenced support surface (P<.05). Muscle spasticity was not affected by vibration (P>.05).
CONCLUSION:
These preliminary results suggest that intensive WBV might potentially be a safe and feasible way to increase some aspect of lower limb muscle strength and postural control in adults with chronic stroke. Further studies should focus on evaluating how the training protocol should be administered for best possible outcome and this compared against other interventions.
Copyright © 2013 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.
KEYWORDS:
AFOs, Ankle-foot orthoses, CON, Control, ES, Equilibrium score, Exercise, FAC, Functional ambulation classification, Rehabilitation, SOT, Sensory organization test, Stroke, Vibration, WBV, Whole body vibration

PMID: 24067865