RESUMO
BACKGROUND: This factorial, assessor-blinded, randomized, and controlled study compared the effects of perturbation-induced step training (lateral waist-pulls), hip muscle strengthening, and their combination, on balance performance, muscle strength, and prospective falls among older adults. METHODS: Community-dwelling older adults were randomized to 4 training groups. Induced step training (IST, n = 25) involved 43 progressive perturbations. Hip abduction strengthening (HST, n = 25) utilized progressive resistance exercises. Combined training (CMB, n = 25) included IST and HST, and the control performed seated flexibility/relaxation exercises (SFR, n = 27). The training involved 36 sessions for a period of 12 weeks. The primary outcomes were the number of recovery steps and first step length, and maximum hip abduction torque. Fall frequency during 12 months after training was determined. RESULTS: Overall, the number of recovery steps was reduced by 31% and depended upon the first step type. IST and CMB increased the rate of more stable single lateral steps pre- and post-training than HST and SFR who used more multiple crossover and sequential steps. The improved rate of lateral steps for CMB exceeded the control (CMB/SFR rate ratio 2.68). First step length was unchanged, and HST alone increased hip torque by 25%. Relative to SFR, the fall rate ratios (falls/person/year) [95% confidence interval] were CMB 0.26 [0.07-0.90], IST 0.44 [0.18-1.08], and HST 0.30 (0.10-0.91). CONCLUSIONS: Balance performance through stepping was best improved by combining perturbation and strength training and not strengthening alone. The interventions reduced future falls by 56%-74% over the control. Lateral balance perturbation training may enhance traditional programs for fall prevention.