The effect of high- and moderate intensity training on fast, preferred and dual task gait speed in elderly community dwelling adults : a three-armed randomized controlled trial
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Background: Gait speed, both preferred and fast, are decreasing with age. Reduced gait speed is associated with disability, mortality and falls. Interventions has shown to improve gait speed, but current research does not agree which interventions that is most effective. Many earlier studies have compared the effect of resistance training and aerobic training on gait speed, but no known study compare different aerobic interventions at different intensity. The main aim of this study was to assess the effect of moderate and high-intensity aerobic training on gait speed; preferred, fast and dual task gait speed. Our second aim was to investigate if gender end baseline leg strength influenced gait speed response to exercise. Materials and methods: This is a randomized controlled trial investigating the effect of training on gait speed in 1567 community-dwelling older individuals, aged 70-76 years. Participants were randomized into either control group (CON), moderate-intensity training (MIT) or high-intensity training (HIT) group. Data were collected at baseline and 3 years. Gait speed data was collected with ProtoKinetics Zeno walkway. We performed both per protocol analysis (ANCOVA) and intention-to-treat analysis (Mixed Model with Repeated Measures), comparing groups pairwise; HIT vs CON, MIT vs CON and HIT vs MIT. Results: In the per protocol analysis, we found significant improvements in preferred (3.1 cm/sec, p=0.002) and fast (3.6 cm/sec, p=0.001) gait speed of HIT when comparing HIT and CON. When comparing MIT and CON, we found no significant differences in any gait condition. Significant difference between MIT and HIT on gait speed response was found, in favor HIT – significant change in preferred gait speed (p=0.003) and near-significant change in fast gait speed (p=0.0058). We found that females had significantly larger improvement in dual task gait speed of both HIT and MIT, as well as female had largest improvement in fast gait speed of HIT when comparing HIT and CON. We found that baseline leg strength significantly influenced improvements in all gait conditions, where larger leg strength was associated with larger improvement in gait speed following both HIT and MIT. Exercise compliance had no effect on gait speed response. When performing intention-to-treat analysis, we found no significant effect of exercise on any gait condition. Conclusion: Our results indicate that HIT was most effective in term of improving preferred and fast gait speed. We found no significant difference in gait speed between CON and MIT, suggesting that MIT alone have no impact on gait speed. No change in dual task gait speed was observed between groups. Both gender and leg strength significantly influenced gait speed response to MIT and HIT.