Efficacy of 24-week instability resistance training on cognitive function of older adults with probable mild cognitive impairment: A randomized, assessor-blinded, sham-controlled trial

OBJECTIVE: To determine the effects of instability resistance training (IRT) on the cognitive function of older adults with probable mild cognitive impairment (MCI). METHODS: This was assessor-blinded, randomized controlled trial which included 162 adults aged ≥65 years, physically independent and who had indicative of MCI. Participants were randomly allocated to either 24-week of twice-weekly IRT (n=80) or active control group (n=82). IRT group underwent resistance exercises on unstable surfaces (i.e., Balance Pad, Bosu® ball), prescribed as seven exercises in 3 sets with target zone ranging between 10-15 repetitions. The active control group performed non-structured (no progression neither complexity), low intensity functional and stretching/relaxation exercises. Cognitive outcomes Executive Function (Stroop Color Task; Digit Symbol Substitution Test; Trail Making Test Part A and B; Digit Span Memory Test; Verbal fluency test) and Memory were assessed at baseline, after 12- and 24-week. Linear mixed modeling, adjusted for sex, age, and baseline levels of each outcome, were used to determine treatment effects. RESULTS: 162 participants with a mean age of 70.4±4.3 years and indicative of MCI (MoCA 20.1±4.2) were included. At 24-week, the IRT group demonstrated significant improvements in executive function performance (Verbal Fluency - Letter A: +1.2 letters; 95% CI 0.2-2.2; p=0.017; Digit Span Forward: +0.7 points; 95% CI 0.1-1.3; p=0.010) compared with active control group. No significant between-group differences were observed in the remaining cognitive outcomes. CONCLUSION: Our findings revealed that 24-week IRT improved executive functioning domains among older adults with probable MCI. TRIAL REGISTRATION: RBR-9bv3dc9.