Design and subjects: In this prospective, randomised, single-blinded controlled trial, approximately 114 healthy seniors (55-70 years old) will be randomly assigned to either the VT group (n~57) or control group (n~57). Interventions: Subjects in the VT group will receive VT reactive balance training (3 hours/week) for 3 months, whereas subjects in the control group will receive no VT training but will jog 3 hours/week during the intervention period.