Neither uni- nor multi-modal exercise interventions improve single- and dual-task gait performance in physically active healthy elderly – a pilot study

Purpose: Aging is an inevitable process leading, inter alia, to the loss of muscle mass as well as the decrease in physical and cognitive function. These age-related impairments translate into a reduced gait performance and an increased risk of falls, which can be tackled with resistance training, Unimodal intervention (UMI). However, Multimodal intervention (MMI), i.e. combined motor-cognitive and resistance training, might be a more promising approach to increase physical and cognitive function in old adults. Therefore, this pilot study aimed to investigate the effects of MMI, compared to UMI, on gait and cognitive performance in elderly participants. We hypothesized that MMI will increase gait and cognitive performance to a larger extent than UMI. Methods: In this two-arm randomized controlled pilot study, 29 healthy active elderly participantswere assigned to MMI (15 participants, 72.0±5.5 years) and UMI (14 participants, 70.1±4.7 years). Both groups trained for 12 weeks, two times a week for 60 min, respectively. MMI consisted of motor-cognitive training directly followed by resistance training, while UMI consisted of a stand-alone resistance training. Three weeks before and after the interventions, gait performance (e.g., stride length, velocity, minimum toe clearance) was assessed during single- and dual-task walking trials using inertial measurement units. During dual-task walking, participants walked and concurrently performed different cognitive tasks in a random order: (i) reaction time task, (ii) N-back-task, and (iii) letter fluency task with two difficulty levels, respectively. Data were analyzed with repeated measures analyses of covariance (Time×Intervention×Condition). Results: Although the analyses of the progression of the external load used during resistance training showed a significant increase over the training period (e.g. leg press p<0.001, η ² _p =0.618), there was no improvement of gait or cognitive performance in active old adults after neither MMI nor UMI. Conclusion: Against our hypothesis, the present pilot study indicated that neither a 12-week MMI nor UMI seems to have a sizable impact on gait parameters and cognitive performance in physically active healthy adults. Still, a significant increase in the external load used during resistance training was observed, implying neuromuscular adaptations, which, however, did not translate into a higher gait and/or cognitive performance.