Similar changes in executive function after moderate resistance training and loadless movement.

Growing evidence suggests that physical exercise may improve cognitive function in the short- and long-term. Aerobic exercise has been studied most extensively. Preliminary work suggests that resistance training also improves cognitive function, particularly executive function. Conversely, most studies found little dose-effect by intensity. Consequently, cognitive benefits may be elicited, at least in part, by the movement rather than the physical exertion of resistance training. The objective here was to examine and compare acute changes in executive function after resistance training and a loadless movement control among young, healthy adults. Twenty-two young healthy adults (mean age 23.4 years [2.4]; 50% female) completed three conditions, a baseline condition and two experimental conditions (moderate intensity resistance training, loadless movement control). Participants completed a computerized modified Stroop task with concurrent electroencephalography (EEG) before and 10, 20, 30, and 40min after each intervention. Outcomes (incongruent and congruent response time, accuracy, EEG P3 amplitude and latency) were analyzed using mixed linear regression models (factors: condition, time, condition*time). There was a main effect of time for Stroop response time (F4,84 = 3.94, p = 0.006 and F4,84 = 10.27, p<0.0001 respectively) and incongruent and congruent P3 amplitude (F4,76 = 4.40, p = 0.003 and F4,76 = 5.09, p = 0.001 respectively). Post-hoc analyses indicated that both incongruent and congruent P3 amplitude were elevated at time points up to and including 40min after the interventions (compared to pre-intervention, p<0.05). Both incongruent and congruent response times were faster at 10min post-intervention than pre-intervention (p<0.04). There was no main effect of condition or interaction between condition and time for either outcome (p≥0.53). Similar improvements in executive function were observed after loadless movement and resistance training, suggesting that movement is at least partially responsible for the benefits to executive function. Future research should continue to probe the influence of movement versus physical exertion in resistance training by including a movement and non-movement control.