['How has adherence been measured in recent prospective studies focusing on adherence to exercise programs among older people? What is the range of adherence rates? Which factors are associated with better adherence?', 'Systematic review of prospective studies that had a primary aim of assessing adherence to exercise programs.', 'Older people undertaking exercise programs.', 'Exercise programs.', 'Measures of adherence, adherence rates and factors associated with adherence.', 'Nine eligible papers were identified. The most common adherence measures were the proportion of participants completing exercise programs (ie, did not cease participation, four studies, range 65 to 86%), proportion of available sessions attended (five studies, range 58 to 77%) and average number of home exercise sessions completed per week (two studies, range 1.5 to 3 times per week). Adherence rates were generally higher in supervised programs. The person-level factors associated with better adherence included: demographic factors (higher socioeconomic status, living alone); health status (fewer health conditions, better self-rated health, taking fewer medications); physical factors (better physical abilities); and psychological factors (better cognitive ability, fewer depressive symptoms).'] Is adherence to exercise programs for older people influenced by program characteristics and personal factors : a systematic review?