Abstract
Introduction: Physical activity (PA) has been associated with physiological and psychological benefits throughout life (Gaertner et al., 2018; McAuley et al., 2013; Raichlen & Alexander, 2017). Yet, large proportions of children are not active enough for the associated benefits (Hillman et al., 2019). In the past decades, researchers have investigated the effects of acute bouts of PA on executive function (EF). This is because typical school-age children are highly dependent on their EF for better academic performance. The enhancement of EF and wellbeing in schools and other learning contexts are of interest to researchers, teachers and stakeholders. Findings suggest that acute PA bouts of between 10 and 30 min, can improve EF (Ai et al., 2021; Chang et al., 2012; Hillman et al., 2019; Schmidt et al., 2021). However, the wealth of these findings on the effects of PA on EF are derived mainly from adults. Furthermore, there is no consensus on children's most appropriate dose response (Hillman et al., 2019). Given the importance of developing EF in school settings and the proposed cognitive benefit of PA, but the low adherence to PA, this thesis sought to examine quantitatively and qualitatively the cognitive and affective approaches benefits of different types and modes of PA in school age children.Methods: The first investigation of this PhD examined the acute effects of a continuous vs an intermittent PA bout of stationary cycling (school-controlled setting). Twenty four participants (14 boys Mage = 10.32 ± .48 years), using a within-subjects counterbalanced crossover design, performed a continuous (70% HRMAX) and an intermittent (≥ 85% HRMAX; 12 bouts: 30 seconds work, 45 seconds rest) PA bout of cycling and a sedentary control condition, both lasting 15 min. Measures of EF (inhibition and verbal and visual working memory) were obtained before, 1 and 30 min post the conditions and self-reporting scales were used to understand the variation in feelings, arousal and physical perceived exertion.
The second study followed a field-based approach similar to the previous investigation and used the same research design and measurements. Twenty-nine participants (16 boys Mage = 9.34 ± .48 years) performed a running self-paced bout (TDM-The Daily Mile™), an intermittent PA running bout (Shuttle Runs: ≥ 85% HRMAX; 12 bouts 30/45 seconds) and a sedentary control condition and the scales of affect as in the first study.
Lastly, the third study examined a mixed-method approach of cognitively demanding PA bouts versus non cognitively demanding (simple PA). Thirty-nine participants aged 9-12 years old (29 boys; Mage= 11 ± 1 years), using a within-subjects counterbalanced design, performed a simple PA bout (SPA) and a cognitively demanding physical activity bout (CDPA) (online-based) for 15 min, which were matched for duration and intensity, and only differed on the cognitive demands. Inhibition was measured before PA, 1 and 30 min after the PA bout and participants’ perceptions of their feelings, arousal, and physical and mental exertion were also collected using self-reported scales. Additionally, 31 children participated in semi-structured focus groups to explore their perceptions of the two types of PA.
Results: The first study shows that when comparing continuous to an intermittent PA bouts of cycling, reaction time improved for the continuous condition at 1 and 30 min post-PA (p = .047). The intermittent condition improved only at 30 min post-PA (p = .021), showing a delayed and more significant benefit from the intermittent PA bout compared to the continuous and sedentary control condition. Verbal working memory was improved for the continuous condition 1 min post-PA only and no effects on visual working memory were observed for both experimental conditions. The affect scales showed that both experimental conditions elicited higher arousal and displeasure as the PA bouts started (p< .05) compared to the control condition. However, these feelings were diminished following PA and participants reported higher values of pleasure than before. The intermittent condition also had increased arousal at 30 min post compared to control.
The second study shows that The Daily Mile™ did not significantly induce EF changes compared to the sedentary control condition (all p > .05). In contrast, the shuttle runs condition improved at 1 min post their rection time (p = .004). No effects on visual or verbal working memory were observed (all p > .05). Furthermore, considering the affect scales, the shuttle runs condition reported higher arousal values at 1 min post compared to the other conditions. Besides this, the shuttle runs condition reported significantly lower values of pleasure throughout the end of the activity. These negative effects were diminished 30 min post-PA and the levels of pleasure were significantly higher than at the baseline.
The third study demonstrates no significant differences in inhibitory and affective responses when comparing SPA vs CDPA, suggesting both have similar benefits. The quantitative results indicate no significant differences in inhibitory responses, affect and physical exertion (all p > .05). However, CDPA induced more mental effort than SPA (p < .05). In the focus groups, four themes were identified: physical exertion (e.g., tiredness), social (e.g., teams/groups), environment (e.g., outdoors and competition) and emotional (e.g., fun/enjoyment). Some children (n = 18) reported that the CDPA condition confused them (i.e., mental exertion) and to make these activities more interesting and enjoyable, suggested activities outdoors (n = 15) and included other children as part of a group/team (n = 19). The findings suggest no additional benefit of CDPA compared to SPA on inhibitory responses, affect and enjoyment. Given the low cost, the easy administration, and the minimal equipment and time involved, either approach may be used in a diversity of contexts (i.e., online, school or outdoors) and are worth exploring the effects of these conditions on other aspects of EF.
Conclusion: The results of this PhD contribute to the progression of this area of research by a) examining different types of PA on EF in school-age children (i.e., school-controlled, field-based and online-based) and showing that high intensity intermittent activities are more efficient on cognitive performance than continuous at moderate intensity and these effects can last from 1 to 30 min post-PA; b) including measures of affect (i.e., feelings and arousal) and have the insights of how children perceive these PA bouts, suggesting that higher intensity intermittent activities might lead to higher levels of arousal and improved reaction time; c) exploring the effects of qualitative types of PA bouts using a mixed method approach exploring factors of enjoyment. Using intermittent PA and/or intermittent CDPA seems to be an alternative approach for designing activities involving children in school rather than the conventional continuous runs. However, considering CDPA or SPA, there are no significant differences in inhibitory and affective responses. Thus either type may be used to promote PA and cognitive responses in school age children.
In sum, using high-intensity intermittent activities can have a more effective and prolonged benefit on cognitive performance (i.e., reaction time) than a continuous activity at moderate intensity, considering cycling and shuttle runs. The cycling and running bouts seem to lead to reaction time benefits, lasting up to 30 minutes post-PA. Additionally, it is important to notice that higher intensity seems more effective on reaction time than a continuous PA bout. However, during these PA bouts, moderate intensity PA led to higher affective responses (i.e., more pleasurable). Given this, using the mentioned PA bouts in core moments of the school day can be an effective tool to enhance cognitive performance in children. Additionally, these are low cost, align with the allocated school break time (15 min), and are easy to administer. Further research needs to consider other types of PA with low or high cognitive demands embedded into PA bouts while exploring other EF domains, chronic effects and ecologically valid approaches
| Date of Award | Dec 2022 |
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| Original language | English |
| Awarding Institution |
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| Supervisor | Emma Eyre (Supervisor), Michael Duncan (Supervisor) & Cain Clark (Supervisor) |