A complexidade da tarefa como variável da dose do exercício físico na promoção da funcionalidade em mulheres idosas: Brain Functional Training

Abstract

Physical exercise is one of the most widespread health practices worldwide, and its prescription has traditionally been guided by classical dose variables such as volume and intensity. However, task complexity has emerged as a relevant component for both movement analysis and physical training, although it still lacks greater theoretical and empirical density. In this context, a training model known as Brain Functional Training (BFT) arises from the premise of increasing task complexity to enhance the activation of brain areas related to movement planning. Accordingly, this thesis investigated the effects and possible mechanisms of manipulating task complexity on the functionality of physically independent older women. In Study I, a theoretical framework was developed, based on a literature review, to support complexity as a variable of exercise dose. The hypothesis was that increasing complexity expands planning demands, elevates acute cognitive load, and more intensely recruits prefrontal regions associated with executive functions, thereby promoting functional adaptations when applied repeatedly. In Study II, the acute effects of different levels of complexity in a squat task were examined on markers of cognitive effort, physical performance, and executive performance in older women. An increase in cognitive effort was observed under more complex conditions, particularly when the squat task was combined with mental calculation or involved unilateral predominance. Despite the higher cognitive cost, no immediate differences were identified between conditions for executive performance. In contrast, increased complexity resulted in longer execution time, reduced movement velocity, and, when complexity was predominantly motor, reduced range of motion. Perceived exertion did not differ between conditions. In Study III, the effects of a 16-week intervention with BFT, functional training, and mind–body interventions were investigated, as well as retention after 16 weeks of detraining, on functionality, executive function, and body composition. All three models promoted similar improvements in functional and executive performance, with partial maintenance after detraining. BFT showed specific advantages in movement under dual-task conditions and inhibitory control, suggesting potential superiority in cognitive demands integrated with movement. All groups also increased appendicular lean mass post-intervention, with a partial decline during the detraining period. It is concluded that task complexity constitutes a promising variable of exercise dose, with acute effects on cognitive effort and motor performance, as well as relevant repeated effects on functionality and cognition in older women.