Progressive ageing of the population has generated an increase in chronic diseases [¹]. The concomitant increases in morbidity create vulnerability and frailty in older persons.

Frailty is a common syndrome in older persons [²]. Signs and symptoms of this problem are believed to factors such as fatigue, weight loss, exhaustion, weakness, slow walking speed, decreased balance, low levels of physical activity, slowed motor processing and performance, social withdrawal, cognitive changes, and increased vulnerability to stressors [^3-6].

Most falls in older persons are caused by frailty [⁷,⁸] and multiple medications [^9-11]. Research from the United Kingdom [¹²], the United States [¹³] and Australia [¹⁴] has shown that falls are a tremendous burden to social and health services. Besides affecting psychological and physical health, fractures from falls often imply hospitalization, thereby increasing morbidity. It has been estimated that total health costs attributable to fall-related injuries will practically triple in the next 50 years. Strategies to prevent the negative consequences of falls are needed. One such strategy is exercise [¹⁵,¹⁶].

Institutionalized older people have less capacity to exercise, and greater osteoarticular deterioration and fatigue than non-institutionalized older people [³]. Improving their physical activity could increase their autonomy and help prevent falls [^17-23]. Fighting sedentary attitudes and promoting physical exercise are growing challenges for physiotherapists and other health professionals working in nursing homes.

Whole body vibration is a type of physical exercise that consists of performing static and dynamic exercises on a platform. These effects of this type of exercise have been studied previously in two studies in nursing home residents [²⁴,²⁵]. The results of these interventions were not conclusive because there are differences in the study protocols and limitations in the study designs. Both studies analysed functional capacity and muscle performance but neither recorded the number of falls.

The aim of the present study is to assess the effect of whole-body vibration training on body balance comparing to exercise without vibration in institutionalized older persons. Secondarily, we will evaluate the effects of training on muscular strength and prevention of falls in this population.

WBV training is a type of physical exercise in which people perform various exercises in a squat position on a platform device. Several studies have shown promising results using this intervention in walking capacity, speed of gait, body balance, and muscle strength in elder adults [^33-40]. Only two trials have evaluated the feasibility of WBV in functional mobility and muscle performance in institutionalized older persons [²⁴,²⁵] to date. Both these trials were small and the variability of the study protocols, comparators, outcome measures and limitations in the studies design made it difficult to reach any definitive conclusions about the effectiveness of WBV in increasing functional capacity of older persons [⁴¹].

Our study design incorporates a significantly larger sample, implements randomization, allocation and blinded outcome assessment, and introduces a longer follow up than previous studies. We consider this design will reveal differences between the two study groups in balance and muscle strength, and secondarily, in preventing falls.

The authors declare that they have no competing interests. The Tecnosport Condition SLU Company (Badalona, Spain) gives the Power plate vibration platforms for this study (Model Pro5 Airdaptive, Power Plate^®). Authors have not received remuneration from Tecnosport Condition SLU Company. The clinical trial will be published independently of the positive or negative results.

MSR and MJMZ develop the design of the randomized clinical trial. DRR and AFV provide the intervention support. FRA contributes to the methods of muscular strength assessment. XBC provide the methodological support. All authors have read and approved the final manuscript.

The pre-publication history for this paper can be accessed here:

http://www.biomedcentral.com/1471-2318/11/89/prepub

Mercè Sitjà i Rabert is a PhD candidate at the Universitat Autònoma de Barcelona, Spain.

We would like to acknowledge the contribution of Blanquerna School of Health Science (Universitat Ramon Llull) for their support to the first author, providing her a special leave to work on her thesis. We also thanks Tecnosport Condition SLU (Badalona, Spain) to give the Power plate vibration platforms for this study (Model Pro5 Airdaptive, Power Plate^®) and Ms.Carolyn Newey (Institut de Recerca de l'Hospital de la Santa Creu i Sant Pau, Barcelona) for help in the editing process of the manuscript.

This study is funded by the Institute for Older Persons and Social Services (IMSERSO), Spanish Ministry of Health, Social Policy and Equality, Project 180/2010.