Effects of metastable resistance training with strength and balance requirements compared to traditional resistance and balance training on cognitive performance in older adults: a randomized controlled trial.

BACKGROUND: While aerobic, resistance, and balance training are commonly used to counteract age-related declines in cognitive and physical functions, evidence for cognitive benefits of metabolic training (i.e., aerobic, resistance) remains inconsistent. In contrast, motor training (i.e., balance, coordination) involving higher task complexity may enhance cognition by engaging brain regions associated with cognitive control processes. Resistance training on unstable devices, also referred to as metastable resistance training (MRT), has been reported to increase metabolic, coordinative, and cognitive demands during exercise, as well as to improve cognitive performance in older adults. This study examined the effect of MRT on cognitive performance compared to traditionally recommended resistance training (T-RT) and balance training (BT). We hypothesized that MRT specifically improves cognitive task performance requiring perceptual processing and attention. METHODS: Eighty-three healthy older adults (mean age 70.5 ± 4.5 years) were matched into three groups which were randomly assigned to either MRT, BT or T-RT programs. Each group trained twice a week for 10 weeks. Cognitive functions were assessed using four tasks targeting working memory, inhibitory control, cognitive flexibility, and perceptual processing. Linear mixed-effects models were applied to examine the effect of MRT on cognitive performance in contrast to BT and T-RT. RESULTS: A significant time-by-group interaction was observed for inhibitory control when contrasting MRT with BT, t(80) = 3.56, p < 0.001, β = 0.42, 95% CI [0.19, 0.65], indicating improved response inhibition following MRT. Additionally, perceptual processing was significantly enhanced when comparing MRT with BT for both reaction time, t(79) = 2.35, p = 0.020, β = 0.19, 95% CI [0.03, 0.35], and accuracy, t(79) = -2.69, p = 0.009, β = -0.26, 95% CI [-0.45, -0.07]. CONCLUSIONS: In contrast to BT, MRT appears to selectively enhance cognitive functions requiring inhibitory control and perceptual processing in older adults. Consequently, metabolic demands associated with MRT may offer additional cognitive benefits beyond the coordinative demands offered by traditional balance training. CLINICAL TRIAL NUMBER: This trial, DRKS00030394, was registered in the German Clinical Trials Register on 16/08/2023.