The intervention comprises a 10-week individually supervised, progressive WBV training done twice a week on a side-alternating device with simultaneous body transferring and slight squatting exercises. At the week one, the duration of a single training bout is 1 x 1 min, and the number of 1 min bouts is weekly increased by one until five bouts is reached. During weeks 4 - 10, the training comprises 5 x 1 min bouts with 1 min rest periods between. During weeks 1 to 3, vibration frequencies are 12 and 18 Hz, which are used alternately. Thereafter, also 26 Hz may be used instead of 18 Hz. In addition, the amplitude of vibration is increased progressively according to a specified protocol. A detailed training diary is kept.

Participants keep fall diaries on daily basis and mail the diaries to the investigators in every month. In case of a reported fall, the investigator contacts the participant and enquires the details of the fall.

The standard Short Physical Performance Battery (SPPB) is used for the assessment of participant's balance, walking speed and chair rising time at the baseline, after the 10 week training and after the subsequent 10 month follow-up.In addition, 4-m maximal walking speed , Timed Up and Go (TUG) test and grip strength are assessed at the same time points.