Inclusion Criteria:  a) aged 60 years or over; b) were prefrail or frail according to Fried's criteria; c) performed the sit-to-stand test alone, with a mobility aid, or researcher's help; d) possessed sufficient physical and cognitive abilities to perform exercise sessions; and e) had a physician authorization to participate.  Exclusion Criteria:  Exclusion criteria included having participated in a structured physical exercise training program in the past six months, prescription of hormone replacement therapy and/or psychotropic drugs, and any unstable cardiovascular event (e.g., myocardial infarction) or complication in the past 6 months.