Physical fitness can interfere with the inhibitory control of children, one of which is static muscle strength (SMF). However, the findings in the literature are insufficient to relate handgrip strength and inhibitory control. Physical exercise has been identified as a strategy for improving cognitive function and some evidence indicates that an acute session of high-intensity interval training (HIIT) causes improvements in executive functions. Furthermore, it is necessary to clarify the dose-response effect of exercise on executive functions in children with different levels of physical fitness.

To investigate the acute implications of two HIIT protocols on inhibitory control in schoolchildren.

The research was carried out in a public school in Belém-PA with 4th grade students and had a sample of 21 children aged 9 to 10 years, with the intention of defining the strength levels, the dynamometry test was applied for stratification of the sample into two groups (more force and less force). In this crossover randomized clinical trial, participants performed two HIIT protocols (Progressive and Tabata) on two days separated by an interval of 72 hours. HIIT Tabata lasted 4 minutes with 8 sets of 20 seconds of maximum effort and 10 seconds of rest. The progressive HIIT lasted 5 minutes, with 5 series of 20 seconds of maximum effort followed by 30, 40, 50, 60 and 20 seconds of passive rest respectively, the exercises used body weight. The inhibitory control was evaluated by the Flanker test and the congruent and incongruent response times were analyzed. The test was performed at rest and repeated 11 minutes after performing the exercises. Results were analyzed by estimation statistics and results expressed as significance (p), range (95%) and effect size (g).

after performing progressive HIIT, a reduction in the reaction time of the incongruent condition of children with less strength was observed (g = -0.277); (p= 0.0224; 95.0% CI -0.537, -0.0774), different for the group with more strength that did not show improvement in the same condition (g=0.0421; p= 0.9; 95.0%CI -0.394, 0.662). No differences were found in congruent reaction time.

We conclude that an acute session of high-intensity exercise with progressive rest can positively affect the incongruent reaction time in inhibitory control tests of children with less strength. However, in this study, children with more strength did not have the same benefit in both models of high-intensity exercise.

This research shows that progressive HIIT can be used as an alternative strategy to benefit children with lower SMF in their inhibitory control and academic performance due to its accessibility and low investment.