Low‐Intensity Whole‐Body Vibration Training to Reduce Fall Risk in Active, Elderly Residents of a Retirement Village

This is the authors' abstract. We don't add key points for this paper.

Falls in elderly adults are recognized as a leading cause of mortality and morbidity.1 Approximately 40% of people aged 75 and older fall each year, and approximately 50% who fracture a hip die in less than 1 year.2 Risk factors include functional performance, such as lower extremity impairments, mobility deficits, gait problems, and balance performance.3 Whole-body vibration training (WBVT) is a new exercise concept that may be beneficial in elderly adults.4-6 One study6 reported that a 2-month program improved walking speed, step length, and maximum standing time on one leg in a WBVT plus physical therapy (PT) group (WBVPT) but not in a PT alone group. The underlying mechanisms of WBVT are unknown. One proposed mechanism is acute enhancement of the stretch-reflex loop7 by heightening the alpha and gamma motoneurons that modulate muscle stiffness, resulting in muscle contraction, or tonic vibration reflex. Vibration may inhibit antagonist muscle activation, reducing counteracting muscle contractions.7 The current study assessed the effect of low-intensity WBVT on gait, balance, and health-related quality of life (HRQOL) in active elderly volunteers. Participants were active residents (11 male, 30 female) from a retirement village (mean age 80.1). Medical practitioner approval was obtained. Three withdrew before study commencement. Volunteers provided written informed consent. The Northern X Regional Ethics Committee approved this study. Volunteers were randomized into two groups. The WBVPT group participated in a PT program before the vibration exercise. WBVT was provided using a whole-body vibration machine using a pivotal (or tilt) mode of vibration.8 Participants stood on the vibration platform with knees bent to approximately 35° of flexion. The vibration stimulus was delivered in four bouts of 75 seconds, with 90 seconds rest between bouts, and was set at an oscillation frequency of 20 Hz, with a peak-to-peak amplitude of 2.0 mm. Blinded testers assessed functional mobility using the Timed Up and Go test, gait and balance using the Tinetti test, balance using the Berg Balance scale, lower limb strength and balance using the sit-to-stand test, and simple gait by measuring time taken and number of steps required to walk a set distance. HRQOL was assessed using the Medical Outcomes Study 36-Item Short Form Health Survey. Differences between baseline and 6 weeks were assessed using the Mann–Whitney U test. Of the 41 volunteers, 38 completed the trial. Significant improvements in the simple gait analysis at 6 weeks (in time and number of steps taken) were observed for the WBVPT group but not for the PT group (Table 1). There were positive trends for social functioning, role-physical, role-emotional, vitality, and the Berg balance test in the WBVPT group and negative trends in the PT group. The current study investigated the effects of low-intensity WBVPT on gait, balance, and HRQOL in active elderly adults and showed improvement in gait and physiological and environmental factors that contribute to fall risk.9 After the 6-week intervention, the time that the WBVPT group took for the gait analysis improved by 3 seconds, and the number of steps decreased by 1.4 seconds. These improvements could reflect a WBV-induced increase in lower limb strength and muscular performance.1 Longer-term effects of vibration intervention on lower limb muscular performance have been reported10 (e.g., jumping power and lower limb extension strength). This study reflects the finding of others that WBVPT is a valuable intervention for improving gait.4, 5 Observed gains may be maintained with a regular regime. A previous study4 found improvement in "gait, body balance, motor capacity and self-rated HRQOL" in elderly nursing home residents. The current study found improvements only in gait. Positive trends were noted in some aspects of HRQOL. Another study of 6 weeks of WBVPT in institutionalized volunteers reported greater improvement in measures of gait and balance for the WBVPT than in the PT controls5 and better attendance for the WBVPT group (96%) than the PT group (86%).5 Measurable improvement was found in the current study using a low-intensity intervention at a lower peak acceleration of 15.7 m/s2 (1.6 G) than in other studies.4, 8 Adherence to the intervention indicated that this intensity was well tolerated and could provide a long-term preventive intervention to maintain lower limb strength to reduce fall risk and concomitant morbidity and mortality. Short sessions of low-intensity WBVPT three times a week for 6 weeks improved gait velocity in active elderly people. Further studies are needed to assess whether the effects of WBVT are maintained in the long term. Conflict of Interest: The editor in chief has reviewed the conflict of interest checklist provided by the authors and has determined that the authors have no financial or any other kind of personal conflicts with this paper. We have had consultancies with the company that produced the machine used in this research. Author Contributions: Calder: development of concept and design, study management, acquisition of data. Mannion: study management, PT intervention, acquisition of data. Metcalf: development of concept and design, provision of randomization list, statistical analyses. All authors contributed to interpretation of the data and drafting the manuscript and gave final approval of the version to be published. Sponsor's Role: None.