OBJECTIVES: To test the feasibility and efficacy of current guidelines for multimodal exercise programs in older adults. DESIGN: Randomized, controlled trial. SETTING: Retirement village. PARTICIPANTS: Thirty-eight subjects (14 men and 24 women) aged 76.6 +/- 6.1. INTERVENTION: A wait list control or 10 weeks of supervised exercise consisting of high-intensity (80% of one-repetition maximum (1RM)) progressive resistance training (PRT) 3 days per week, moderate-intensity (rating of perceived exertion 11 to 14/20) aerobic training 2 days per week, and progressive balance training 1 day per week. MEASUREMENTS: Blinded assessments of dynamic muscle strength (1RM), balance, 6-minute walk, gait velocity, chair stand, stair climb, depressive symptoms, self-efficacy, and habitual physical activity level. RESULTS: Higher baseline strength and psychological well-being were associated with better functional performance. Strength gains over 10 weeks averaged 39+/-31% in exercise, versus 21+/-24% in controls (P=.10), with greater improvements in hip flexion (P=.01), hip abduction (P=.02), and chest press (P=.04) in the exercise group. Strength adaptations were greatest in exercises in which the intended continuous progressive overload was achieved. Stair climb power (12.3+/-15%, P=.002) and chair stand time (-7.1+/-15%, P=.006) improved significantly and similarly in both groups. Reduction in depressive symptoms was significantly related to compliance (attendance rate r=-0.568, P=.009, PRT progression in loading r=-0.587, P=.02, and total volume of aerobic training r=-0.541, P=.01), as well as improvements in muscle strength (r=-0.498, P=.002). CONCLUSION: Robust physical and psychological adaptations to exercise are linked, although volumes and intensities of multiple exercise modalities sufficient to cause significant adaptation appear difficult to prescribe and adhere to simultaneously in older adults.