Effects of the FITKids randomized controlled trial on executive control and brain function

Abstract

Objective: To assess the effect of a physical activity (PA) intervention on brain and behavioral indices of executive control in preadolescent children.

Methods: Two hundred twenty-one children (7-9 years) were randomly assigned to a 9-month afterschool PA program or a wait-list control. In addition to changes in fitness (maximal oxygen consumption), electrical activity in the brain (P3-ERP) and behavioral measures (accuracy, reaction time) of executive control were collected by using tasks that modulated attentional inhibition and cognitive flexibility.

Results: Fitness improved more among intervention participants from pretest to posttest compared with the wait-list control (1.3 mL/kg per minute, 95% confidence interval [CI]: 0.3 to 2.4; d = 0.34 for group difference in pre-to-post change score). Intervention participants exhibited greater improvements from pretest to posttest in inhibition (3.2%, 95% CI: 0.0 to 6.5; d = 0.27) and cognitive flexibility (4.8%, 95% CI: 1.1 to 8.4; d = 0.35 for group difference in pre-to-post change score) compared with control. Only the intervention group increased attentional resources from pretest to posttest during tasks requiring increased inhibition (1.4 µV, 95% CI: 0.3 to 2.6; d = 0.34) and cognitive flexibility (1.5 µV, 95% CI: 0.6 to 2.5; d = 0.43). Finally, improvements in brain function on the inhibition task (r = 0.22) and performance on the flexibility task correlated with intervention attendance (r = 0.24).

Conclusions: The intervention enhanced cognitive performance and brain function during tasks requiring greater executive control. These findings demonstrate a causal effect of a PA program on executive control, and provide support for PA for improving childhood cognition and brain health.

Trial registration: ClinicalTrials.gov NCT01334359.

Keywords: aerobic fitness; cognition; physical activity; randomized controlled trial.

FIGURE 1

Flow diagram of the FITKids intervention.

FIGURE 2

Change in response accuracy (mean ± SE) from pre- to posttest as a function of group and cognitive task.

FIGURE 3

Topographic scalp distribution of the change in P3 amplitude (spectrum scale: blue to red) during the flanker task (top) and switch task (bottom) is illustrated for the intervention group (left) and wait-list group (right). As shown, P3 amplitude was greater in the intervention group at posttest only for the conditions that required the greatest amount of executive control across both tasks as denoted by the greater amount of red depicted in the electrophysiological plots representing brain function.

FIGURE 4

Scatterplots of the relationship between attendance at the FITKids afterschool PA program and pre- to posttest change in P3 amplitude to the incongruent condition of the flanker task (A), change in P3 latency to the incongruent condition of the flanker task (B), change in response accuracy for the homogenous condition of the switch task (C), and change in response accuracy for the heterogeneous condition of the switch task (D).