Discussion
post-fall syndrome, cognitive impairment
RECURRENCE, FEMINIZATION
We aimed to compare the effects of a mixed dual-task protocol training in which participants underwent initially SMT and SDT interchangeably and progressed strictly with SDT regarding a control protocol in which participants only performed SMT and SDT activities alternately. Contrary to what we expected, participants of the experimental protocol did not improve their gait performance, functional mobility, static and dynamic body balance, and cognition function compared to the participants of the control protocol over 24 weeks. However, the performance of both groups improved in some functional outcomes after 24 weeks. Also, the gains obtained after the 24-week follow-up post-intervention period for both groups were not maintained for the following 24 weeks post-intervention.Although the functional balance, mobility, and cognition of participants in both groups have improved, the gait speed under SDT (primary outcome) and most of the gait spatiotemporal parameters did not change, except for the MTC. This result can be explained by the principle of training specificity, in which it is highlighted that the adaptations achieved during training are strongly associated with the mode, frequency, and duration of the proposed exercise (Another explanation for our results concerning gait speed is based on the study by An almost 20% reduction in the MTC in all gait conditions caught our attention, as we expected that this outcome would increase and not decrease from the protocol training. We know that the lower the minimum toe clearance, the greater the risk of falls, as this gait parameter is strongly linked to unintentional contact of the foot with the floor (Our results regarding cognitive performance support the points raised before even more. Both groups improved sustained and alternating attention, mental flexibility, visual processing speed, and manual motor function, as assessed by versions A and B of TMT. Participants from both groups also showed improvement in selective attention and aspects of executive functions, such as cognitive flexibility and susceptibility to interference. Although these are very positive results for cognitive reserve, they may have been the cause of the increase in gait automatism and consequent reduction of the MTC after the 24-week intervention.In addition to cognitive function, both protocols improved static and dynamic balance. Physical exercise induces structural plasticity in the human brain, which results in an improvement in cognitive functions which are directly related to balance, such as visual and vestibular functions (The higher proportion of older women in this study must be addressed. The multifaceted phenomenon known as feminization of aging, in which more and more women are accounted for in the older population, especially in Brazil (The strengths of this study include (i) the rigorous randomized controlled trial methodology; (ii) the adoption of a more robust statistical model (GLMM) to minimize the negative impact of missing data, although it was relatively compensated by the sample size calculation that included 20% of expected dropouts; (iii) the relatively long-term intervention and follow-up periods which took place over 24 weeks each. In this study we have chosen to investigate a novel mixed dual task protocol. We also chose on maintaining a longer intervention period (6 months). However, adding some physical multicomponent throughout a short-term intervention period can be considered in future studies regarding dual-task protocol training.Some limitations need to be considered as well. Our results should be considered only for older adults with a low level of cognitive impairment and gait speed equal to or higher than 1 m/s, and participants with no recurrence of falls. The results may not be the same in those individuals with recurrent falls and even those with post-fall syndrome.