The effects of different physical activities on children’s executive functions and academic achievement. A chronic intervention study

Children derive cognitive benefits from both acute and chronic physical activities (PA). Most studies assessed the effect of quantitative aspects of PA, based on intensity and duration considerations. Since it is known that not all forms of PA benefit cognition equally, also qualitative aspects of PA (e.g. exercise types) are gaining attention (Diamond, 2015; Pesce & Ben-Soussan, 2016). Previous chronic studies particularly focused on aerobic physical activities without regard for the cognitive demands inherent in the performed aerobic PA (Schmidt et al., 2015). It is ambiguous whether cognition benefit from the “pure” aerobic activity in terms of increased heart rate or enhanced aerobic fitness, or from the achieved cognitive efforts to perform a specific aerobic exercise. How exercise interventions influence children’s cognition and especially executive functions (EF) in terms of specific characteristics is largely unknown and only rarely has been published. Since executive functions are strongly related to academic achievement (Diamond, 2013), recommendations in terms of the qualitative aspects of PA are not only a recent focus in the field of research, but also important from a practical point of view, for example in the educational setting and in particular for designing school-based PA programs targeting an effective promotion of cognitive performance. Method The aim of the present study was to examine the effects of three qualitatively different chronic PA interventions on executive functions in primary school children. It was hypothesized that a combination of cognitive engagement and physical exertion of physical activity breaks would have a stronger impact on children’s EF than one of these factors alone. A total of 142 children aged between 7 and 9 years (M = 7.91, SD = .40; 54.9 % girls) were allocated to a 20-week classroom-based PA program with either a) a high level of physical exertion and high cognitive engagement (combo group), b) with high physical exertion but low cognitive engagement (aerobic group), and c) with high cognitive engagement and low physical exertion (cognition group). Executive functions (updating, inhibition, shifting) and academic achievement (mathematics, writing and reading) were measured in a pre- and post-test. In the main analyses, ANCOVAs were conducted using the pre-test as covariate. The level of significance was set at p< .05 for all analyses. Results To test the main hypotheses of the study, the three groups were compared regarding their improvement in the different EF subdimensions between pre- and post-test. The three separate ANCOVAs revealed that updating (F(2, 138) = .16, p = .866, partial eta-square = .002) and inhibition (F(2, 138) = .68, p = .507, partial eta-squared = .010) did not differ significantly between the three groups. However, shifting differed significantly between the groups (F(2, 138) = 4.68, p = .011, partial eta-squared = .064), with post-hoc tests revealing a stronger improvement in the combo group compared to the aerobic group (p = .003), but not compared to the cognition group (p = .176). The aerobic and cognition group did not differ from each other (p = .095). For academic achievement, mathematics differed significantly between the three groups (F(2, 138) = 7.34, p = .001, partial eta-squared = .054), with post-hoc tests revealing both the combo group (p = .001) and the cognition group (p = .002) to have a greater impact on children’s mathematic performance compared to the aerobic group. The two cognitively engaging interventions did not differ from each other (p = .901). No changes between pre- and posttest in reading (F(2, 138) = 1.46, p = .236, partial eta-squared = .021) and writing (F(2, 138) = 1.26, p = .287, partial eta-squared = .018) were observed. Discussion The aim of the present study was to investigate the effects of three qualitatively different PA interventions with distinguishable degrees of cognitive engagement and physical exertion on children’s EFs. It was hypothesized that a combination of both would have a stronger impact on children’s EF than one of these factors alone. In summary, the results showed (1) that the two cognitively challenging interventions enhanced children’s mathematic performance more than the aerobic group intervention and (2) that only the combo group intervention fostered pronounced increases in children’s shifting performance. The two EF subdimensions updating and inhibition as well as the academic performance (reading and spelling) remained unaffected. To bring up a suitable theoretical framework, which can explain the current findings, the strength model of self-control revised by Audiffren and André (2015) needs to be addressed: Self-regulation and executive functions share effort as a resource to perform stressful or attentional demanding task such as cognitively challenging physical activities. If children engage in behaviors requiring a lot of effort, the cognitive resource is depleted in a subsequent task. However, the training hypotheses postulates in analogy to a muscle, that the self-control capacity decreases after an acute, but increases after chronic exercises. An overload of cognitive capacities performing cognitively engaging physical activity may lead to an immediate decrease but increases after recovery through a chronic intervention. Two previous studies (Jäger et al., 2015; Schmidt et al., 2015) investigating acute as well as chronic effects of cognitive engaging physical activity on children’s EF may underline these suggestions. Both cognitive challenging PA interventions (combo group and cognition group) showed an increased mathematic performance after the 20-week intervention. This result is not surprising with respect to the successful enhancement of shifting performance for the combo group. Particularly shifting as one EF subdimension, seem to especially mathematic performance as shown by Yeniad and colleagues (2013). The relationship between shifting and mathematic performance can be explained by gains of shifting abilities, which are in turn needed to perform in different problem-solving strategies: shift flexibly attention to relevant tasks and to move back and forth between different types of task. Hence, these requirements are needed, when trying to solve a complex math problem. Like any study, the present study has certain limitations, which need to be addressed. The assessment of EF using only one task for each EF subdimension was probably not ideal but with respect to ecologically valid implementations and high time exposedness for children, it was the only way to test all three subdimensions together. However, including all three EF dimensions is a benefit to give a concrete practical advice. The results suggest promoting particularly shifting performance through classroom-based PA. Further, the current study lacks of an adjusted individual level of cognitive engagement and physical exertion during the physical activity breaks. A cognitive under- or overload might be prevented by examining in advance relevant individual characteristics in sport-specific cognitive expertise, gross motor coordination and physical fitness (Pesce, 2009). Consequently, a personally fitted intervention for each subject would be possible. However, due to room and time limitations, implementing an individualized cognitive and physical level is a challenge for future studies, especially for chronic classroom-based PA interventions. In conclusion, only a combination of PA with a high amount of cognitive engagement leads to a stronger improvement in EFs, although not all EF subdimensions seem to be affected equally. Shifting as one EF domain and its relatedness to academic achievement seems to be sensitive with regard to cognitive engaging physical activities within the preadolescent period and should be focused in future classroom-based PA interventions. References Audiffren, M., & André, N. (2015). The strength model of self-control revisited: Linking acute and chronic effects of exercise on executive functions. Journal of Sport and Health Science, 4(1), 30–46. Diamond, A. (2013). Executive functions. Annual Review of Psychology, 64, 135–168. Diamond, A. (2015). Effects of physical exercise on executive functions: Going beyond simply moving to moving with thought. Annals of Sports Medicine and Research, 2(1), 1011. Jäger, K., Schmidt, M., Conzelmann, A., & Roebers, C. M. (2015). The effects of qualitatively different acute physical activity interventions in real-world settings on executive functions in preadolescent children. Mental Health and Physical Activity, 9, 1–9. Pesce, C. (2009). An integrated approach to the effect of acute and chronic exercise on cognition: the linked role of individual and task constraints. In T. McMorris, P. D. Tomporowski, & M. Audiffren (Eds.), Exercise and cognitive function. Chichester, UK, Hoboken, NJ: Wiley-Heinrich. Pesce, C., & Ben-Soussan, T. D. (2016). “Cogito ergo sum” or “ambulo ergo sum”? New perspectives in developmental exercise and cognition research. In T. McMorris (Ed.), Exercise-Cognition Interaction. Neuroscience Perspectives (pp. 251–282). London: Elsevier. Schmidt, M., Jäger, K., Egger, F., Roebers, C. M., & Conzelmann, A. (2015). Cognitively engaging chronic physical activity, but not aerobic exercise, affects executive functions in primary school children: a group-randomized controlled trial. Journal of Sport and Exercise Psychology, 37(6), 575–591. Yeniad, N., Malda, M., Mesman, J., van Ijzendoorn, M. H., Pieper, S., & van Ijzendoorn, M. H. (2013). Shifting ability predicts math and reading performance in children: a meta-analytical study. Learning and Individual Differences, 23, 1–9