Scand J Med Sci Sports 2015: 25: e331–e338 doi: 10.1111/sms.12310
© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd
Acute physical activity and delayed attention in primary school students M. C. Gallotta1*, G. P. Emerenziani1*, E. Franciosi1, M. Meucci2, L. Guidetti1†, C. Baldari1† Department of Movement, Human and Health Sciences, University of Rome “Foro Italico,” Rome, Italy, 2Department of Health and Exercise Science, Appalachian State University, Boone, North Carolina, USA Corresponding author: Carlo Baldari, University of Rome “Foro Italico,” Piazza Lauro De Bosis, 6, I-00135 Rome, Italy. Tel: 0039 06 36733227, Fax: 0039 06 36733211, E-mail: [email protected]
1
Accepted for publication 15 July 2014
To examine the influence of different types of exertion on immediate and delayed attention in 116 primary school children divided in three groups of exertion [cognitive exertion – CE (school curricular lesson), physical exertion – PE (traditional physical education lesson), mixed cognitive and physical exertion – CPE (coordinative physical education lesson)]. CPE was the combination of physical load due to the practice of physical exercises and of cognitive load requested to perform movement-based problem solving tasks requiring accurate timing, temporal estimations, temporal production, and spatial adjustments. Children’s attentional capacity was tested before (pre) and after (at 0 min and at 50 min post) a CE, a PE,
or a CPE lesson, using the d2-test of attention, and analyzed using a 3 × 3 × 2 mixed analysis of covariance with exertion type and time as within factors, gender as between factor, and baseline data as covariate. Effect sizes were calculated as partial eta squared (ƞ2). Results showed that participants’ attentional performance was significantly affected by exertion type (P < 0.0001), by time (P < 0.0001) and by exertion type × time interactions (P < 0.0001). The effect sizes ranged from medium (0.039) to large (0.437). Varying the type of exertion has different beneficial influences on the level of attention in school children.
School teachers often claim that pupils’ cognitive and academic performances were impaired after physical education classes. Therefore, numerous studies have been conducted to demonstrate the facilitating effect of physical exercise on cognitive functions (Raviv & Low, 1990; Pellegrini & Davis, 1993; Mahar et al., 2006; Budde et al., 2010b; Niemann et al., 2013). Recently, it has been shown that acute exercise can be beneficial for children’s mental functions (Tomporowski, 2003a; Tomporowski et al., 2011; Verburgh et al., 2014). However, the relationship between physical exercise and cognitive function is very complex since the improvement of children’s cognitive functions after acute exercise can depend on duration (McNaughten & Gabbard, 1993), intensity (Tomporowski, 2003a; Kamijo et al., 2007; Budde et al., 2010b), and specific type (Raviv & Low, 1990; Budde et al., 2008; Tomporowski et al., 2008; Pesce et al., 2009) of physical exercises performed during physical activity interventions. Moreover, acute exercise-induced modifications on cognitive performances are determined by the interactive effects between
acute and chronic exercise (Budde et al., 2012). Many studies revealed that acute physical exercises could induce beneficial effects on children’s and adolescents’ response speed and accuracy (Tomporowski, 2003b), memory (Pesce et al., 2009; Budde et al., 2010b), attention, and concentration capacity (Gallotta et al., 2012; Niemann et al., 2013) by positively influencing the physiological arousal (Lambourne & Tomporowski, 2010), changing brain neurochemistry (Ellemberg & St. Louis Deschenes, 2010), increasing steroid hormones’ concentration (Budde et al., 2010b) and cerebral blood flow (Tomporowski, 2003a; Ellemberg & St. Louis Deschenes, 2010), inducing an excitement of cerebellum and prefrontal cortex (Serrien et al., 2006, 2007; Diedrichsen et al., 2007; Budde et al., 2008), and brainderived neurotrophic factor (BDNF) activity (Hung et al., 2013). In school context, attention and concentration capacities assume an important role being key elements in the learning process (Zervas & Stambulova, 1999). Indeed, pupils often reduce their attention and concentration across school time for prolonged periods of academic instruction (Pellegrini & Davis, 1993; Budde et al., 2008) because of mental operations conducted in the process of learning in class (Raviv & Low, 1990). To investigate the possible role of exercise in the
*The contribution of these first two authors must be considered equal. † The contribution of these last two authors must be considered equal.
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Gallotta et al. school setting, researchers have investigated the effect of acute physical activity on cognitive abilities and memory (Budde et al., 2010b; Gallotta et al., 2012). However, few studies that investigated the possible influence of qualitative aspects of acute physical activity (type of physical activity) were conducted on children’s attentional performance (Budde et al., 2008; Gallotta et al., 2012; Niemann et al., 2013) even though the quality of motor experiences might contribute not only to physical and lifestyle development (Bailey, 2006; Fairclough et al., 2013), but also to cognitive development (Taras, 2005). Therefore, physical education could represent an essential instrument to offer children a quality experience of physical activity improving cognitive function and facilitating the learning process. The aim of this study was to examine the potential influence of different types of exertion on primary school children’s attentional duration (immediate and delayed attention) in three consecutive moments (before, immediately after, and after 50 min). We hypothesized that exercise-induced arousal following acute exercise could induce a consequent facilitation of attentional performance. This facilitation could probably be due to the activation of some specific neuronal structures common to cognition and movement coordination (Budde et al., 2008) or to a change in steroid hormones concentration after exercise which was observed both in children (Budde et al., 2010c) and adolescents (Budde et al., 2010a, b). According to the theoretical background, we investigated the possible role that different types of acute physical activity could have on immediate and delayed attention in primary school student’s comparing the level and quality of their attention immediately before (pre), immediately after (at 0 min post), and 50 min after three different types of school lessons. School lessons were a traditional physical education lesson, corresponding to physical exertion (PE), a coordinative physical education lesson, corresponding to a mixed cognitive and physical exertion (CPE), and a school curricular lesson, corresponding to cognitive exertion (CE). By proposing the same exercise intensity in both physical education lessons, according to the guidelines for school health physical activity programs to promote healthy behavior among children (Centers for Disease Control and Prevention, 1997), we hypothesized that their different qualitative type might induce significant differences on children’s attentional performance across time. In fact, while the heart rate (HR) was controlled to impose the same exercise intensity, the main difference between the two physical education lessons was induced by the manipulation of qualitative aspects of the physical activity intervention concerning the level and variety of coordinative demands of the teaching contents (Mechling, 1999). Specifically, PE was structured focusing on endurance exercises for cardiovascular health, while CPE was structured focusing on the high variability of motor coordination and skill learning demands.
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Materials and methods Study design The study was designed as a cluster-randomized controlled intervention in all classes (from grade 3 to grade 5) of a single primary school in Rome, Italy. The unit of randomization was the participating class. Nine classes with a total sample of 116 school children participated. The researcher randomized the nine classes into three groups of intervention. There were three classes in each intervention group.
Participants One hundred and sixteen school children aged between 8 and 11 years volunteered to participate in this study. The classes were two of grade 3 with a total of 36 children (8–9 years of age), three of grade 4 with a total of 26 children (9–10 years of age), and four of grade 5 with a total of 54 children (10–11 years of age), respectively. After cluster randomization, thirty-nine participants were in the cognitive exertion group (CE), 31 participants in the physical exertion group (PE), and the remaining 46 participants in the cognitive plus physical exertion group (CPE). Children were eligible if they had no learning and academic difficulties, attention-deficit disorders, neurological and developmental disorders, dyslexia, medical conditions that would affect study results or limit physical activity. The Institutional Review Board of the University of Rome “Foro Italico” approved this investigation. Written informed consent forms were obtained from both parents and children prior to study participation.
Procedures Each group participated in one of the three experimental sessions corresponding to a different type of exertion [cognitive (CE), physical (PE), cognitive plus physical exertion (CPE)]. Children completed the same attentional test before (pre) and after 0 min and 50 min (post) the experimental session. Experimental sessions occurred in the morning, at the same time of the school day. The CE consisted of a 50-min academic class about humanistic subject matters (Decree of the President of the Republic of Italy n. 254 of 16 November 2012, 2013). The PE and CPE were equivalent in structure, total duration (50 min) and intensity. Both lessons started with 15 min of warmup, followed with 30 min of continuous moderate to vigorous physical activities (MVPA), and ended with 5 min of cool-down and stretching. All children were equipped with HR monitors during both physical activity lessons. The exercise intensity of both lessons was monitored by recording HR using a HR monitor (S610i; Polar Electro Oy, Kempele, Finland) in order to establish exertion in the MVPA range of a HR > 139 bpm (Wang et al., 2005). At this purpose, we set HR target zones (MVPA) on the HR monitor prior to exercise: an alarm sounded if child’s HR was below the MVPA zone to control HR and maintain a continuous MVPA during all session avoiding differences between lessons (Fig. 1). The CE and CPE differed only in type of physical activities that children were engaged in. The PE consisted of continuous aerobic circuit training (Weineck, 2007) followed by a submaximal shuttle run exercise. This lesson was focused on the improvement of cardiovascular endurance by performing different types of gaits (e.g., fast walking, running, skipping) without any specific coordinative request (Decree of the President of the Republic of Italy n. 254 of 16 November 2012, 2013). The PE provided changes in executive modalities and some variations of intensity, but not rest periods. The CPE consisted of the sport-unspecific use of basketballs in the context of mini-games. The basketballs were used in
Physical exertion and delayed attention
Fig. 1. Individual graphs of HR during CPE and PE lessons. unconventional ways with varying game rules (e.g., use of footeye coordination techniques with basketballs; Gallotta et al., 2009; Gallotta, 2010). This lesson was geared toward the development of both motor control and perceptual-motor adaptation abilities. The high variability in the activities aimed to contribute to a multilateral development of coordinative abilities (Roth, 1982). This lesson was focused on the development of psychomotor competences and expertise in movement-based problem solving through functional use of a common tool (e.g., basketball), and considering various tasks that involved decision-making motor tasks and manipulative ball handling skills (e.g., bouncing, throwing, receiving a ball, and their combination). CPE resulted from the combination of physical load due to the practice of physical exercises and of cognitive load requested to perform movementbased problem solving and decision-making tasks requiring accurate timing, temporal estimations, temporal production, spatial and temporal adjustments, and spatial and temporal orientation that were essential parts of the cognitive requirements to perform such a kind of activities (Buscà et al., 2011). The CPE aimed to develop both motor control abilities and perceptual-motor adaptation abilities, by combining demands on gross-motor and manipulative control abilities and perceptual-motor adaptation abilities (particularly kinesthetic differentiation and response orientation). After completing the experimental session, participants moved quickly to the classroom to continue the scheduled school day attending a 50-min academic class.
Experimental measures Immediately, pre and post and 50 min post each exertion session, children completed the d2-test of attention (Brickenkamp & Zillmer, 1998) developed to measure sustained attention and concentration under stress induced by a completion time. The d2-test is a paper and pencil letter-cancellation test that consists of 14 different lines each one composed by 47 randomly mixed letters (p, d) with one to four single and/or double quotation marks either over and/or under each letter. Children were required to mark, within 20 s for each line, only the letters “d” that have double quotation marks either above or below them. The test lasted 4.67 min. Each child’s score was determined by the total number of items processed (TN) within the d2-test, by the number of letters correctly marked minus errors committed (CP) and by the percentage of errors (E%) made within all items processed. TN
was a measure of processing speed and amount of work completed, CP was a measure of concentration performance, and E% was a measure of performance quality. A low error rate indicated high-quality performance. The range of the test reliability was between 0.95 and 0.98 and the validity coefficient was 0.47 (Brickenkamp & Zillmer, 1998). The d2-test determines the capacity to focus on one stimulus/ fact, while suppressing awareness to competing distractors (Brickenkamp & Zillmer, 1998). Processes of selective attention are also required for successful completion since not only the letter “d” is orthographically similar to the letter “p,” but there are many distractor letters “d” with more than two dashes (Brickenkamp & Zillmer, 1998). The performance on this test reflects visual perceptual speed and concentrative capacities.
Statistical analysis All results were expressed as mean ± standard deviation. According to a previous study (Gallotta et al., 2012), individual scores (TN, E%, CP) were analyzed using a 3 × 3 × 2 mixed analysis of covariance with exertion type (CE vs PE vs CPE) and time (pre vs 0′ post vs 50′ post) as within factors, gender (male vs female) as between factor, and baseline data as covariate. Effect size was also calculate using Cohen’s definition of small, medium, and large effect size (as partial ƞ2 = 0.01, 0.06, 0.14). Significant interactions were further analyzed by means of Bonferroni post-hoc analysis. Within the gender factor, differences in the baseline attentional variable scores of males and females were verified using an analysis of variance (ANOVA) comparison. Moreover, for each attentional variable score evaluated after the intervention, we calculated the absolute variation (Δ) and the percentage of variation (Δ%) with respect to its pre-intervention value (0′ postintervention – pre-intervention value and 50′ post-intervention – pre-intervention value) for CE, PE, and CPE group, respectively. ANOVA for repeated measures was then performed to examine the effect of exertion type (CE vs PE vs CPE), gender (male vs female), and time on absolute variation (Δ) and on the percentage of variation (Δ%) in each attentional variable, followed by posthoc analysis (Bonferroni adjustment) to determine effects within the three exertion types. Significant differences between PE and CPE exercise intensity were verified by means of planned pairwise comparison (t-test). Statistical significance was defined as P ≤ 0.05.
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Exertion type Time Exertion type × time Gender Exertion type Time Exertion type × time Exertion type Time
10.44 49.26 25.48 6.29 42.35 4.43 3.42 13.18 12.41
2 2 4 1 2 2 4 2 2
< 0.0001 < 0.0001 < 0.0001 < 0.05 < 0.0001 < 0.01 = 0.01 < 0.0001 < 0.0001
0.161 0.311 0.319 0.055 0.437 0.039 0.059 0.195 0.102
E% CP
CP, number of letters correctly marked minus errors committed; E%, percentage of errors; TN, total number of items processed.
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457.65 ± 115.46 2.30 ± 2.75 193.93 ± 58.04* 443.85 ± 103.99‡ 1.85 ± 2.05 181.89 ± 45.28‡ 544.30 ± 83.45† 22.15 ± 2.17 119.53 ± 35.77† 510.43 ± 89.83* 22.86 ± 2.875 108.87 ± 38.25* 430.53 ± 106.86‡ 23.33 ± 2.33‡ 80.74 ± 31.26‡
50' post 0' post Pre 0' post
50' post
CPE
431.71 ± 67.14† 2.61 ± 4.13 170.71 ± 35.43†
50' post
*P ≤ 0.05 0' post vs pre. † P ≤ 0.05 50' post vs 0' post. ‡ P ≤ 0.05 50' post vs pre. CP, number of letters correctly marked minus errors committed; E%, percentage of errors; TN, total number of items processed.
TN
414.19 ± 70.50* 2.70 ± 4.34 162.81 ± 34.26*
Partial η2
355.06 ± 65.29‡ 2.77 ± 4.37 139.80 ± 31.04‡
P
TN E% CP
d.f.
Pre
F
0' post
Factors
Pre
Variable
CE
Table 1. Significant analysis of covariance results on attentional test scores
PE
Table 1 reports only significant results that are relevant for the present study: main effects of exertion type, time, gender, and exertion type × time interactions. Differences in the baseline attentional variable scores for each exertion type were verified (P < 0.0001). Moreover, differences in the baseline attentional variable scores of males and females were verified (P < 0.05), but no significant effects of gender were revealed. Children significantly improved their TN, CP, and E% individual values after intervention (P < 0.0001). Moreover, exertion type × time interaction indicates the likely presence of differential effects of the exertion type on TN and E% variables change after intervention. Females’ TN values were significantly higher than males’ TN values (474.21 ± 97.56 vs 436.51 ± 108.76 scores, respectively). Table 2 shows pre-, 0′ post-, and 50′ postintervention individual scores and indicates that children improved their performances from pre- to 0′ post-, and to 50′ post-intervention to a lower degree when exerted in CPE condition as compared with both CE and PE conditions. Improvement across intervention for all three groups was analyzed using absolute variation (Δ) and percentage of variation (Δ%). ANOVA revealed a significant main effect of exertion type on ΔTN (F2,113 = 35.65, P < 0.0001, η2 = 0.393) and on ΔCP (F1,113 = 8.15, P = 0.001, η2 = 0.129), a significant main effect of time on ΔTN (F1,113 = 37.49, P < 0.0001, η2 = 0.254), on ΔE% (F1,113 = 8.44, P < 0.01, η2 = 0.071) and on ΔCP (F2,113 = 10.91, P < 0.001, η2 = 0.090). Moreover, ANOVA revealed a significant main effect of exertion type on Δ%TN (F2,113 = 24.75, P < 0.0001, η2 = 0.310) and on Δ%CP (F2,113 = 18.67, P < 0.0001, η2 = 0.253), a significant main effect of time on Δ%TN (F1,113 = 41.53, P < 0.0001, η2 = 0.274) and on Δ%CP (F1,113 = 20.59, P < 0.0001, η2 = 0.158), and finally and exertion type × time interaction on Δ%CP (F2,113 = 4.82, P = 0.010, η2 = 0.081). These results revealed that CPE exertion type led to a lower improvement of CP values over the time than the two others exertion conditions (Fig. 2).
Table 2. Pre-, 0' post-, and 50' post-intervention individual scores (mean values ± standard deviation) for physical exertion (PE), cognitive exertion (CE), mixed cognitive, and physical exertion (CPE) group
Results
477.24 ± 99.43† 1.50 ± 1.60† 198.93 ± 47.50
Gallotta et al.
Physical exertion and delayed attention
Fig. 2. Percentage of variation (Δ%) of concentration performance (CP) (±SEM). *P < 0.05 0′ post – pre vs 50′ post – pre.
HR monitoring verified that both physical education lessons (PE and CPE) had similar exercise intensity (146.56 ± 14.09 and 147.25 ± 15.50 bpm, respectively). Discussion This study investigated the potential influence of different types of exertion on pupil’s attentional performance across time. In all three groups, TN and CP scores significantly changed over time with a large and medium effect size, respectively. Specifically, school children showed higher working speed and concentration scores at 0′ post and 50′ post each exertion session rather than at the beginning (Table 2). The improvements in performance that arose through practice and being more familiar with the test requirements should be considered. Westhoff and Dewald (1990) proved that performance in concentration tests could be improved through repetition, but practice effects did not transfer from one concentration test to another. However, the validity and reliability of the d2-test of attention was documented by a large volume of research, proving the high test-retest reliability of the test (Brickenkamp & Zillmer, 1998). However, because of the improvement of TN and CP scores over the time in all three groups, we cannot separate a general effect of acute exercise from a learning effect, which might interfere with the impact of the compounds on attention. Therefore, to exclude the influence of the learning effect on attentional performance across time, the learning effect was controlled using baseline data as covariate (Gallotta et al., 2012). Thus, our results showed a significant effect of exertion type on the attentional variables measured over time. We could speculate that our results support the hypothesis about the facilitation of attentional performance caused by maintenance of exercise-induced arousal following acute exercise. This facilitating effect could be the result of an increase in steroid hormones’ concentration (Budde et al., 2010b), changes in brain
neurochemistry (Ellemberg & St. Louis Deschenes, 2010), increase in cerebral blood flow (Tomporowski, 2003a; Ellemberg & St. Louis Deschenes, 2010), excitement of cerebellum and prefrontal cortex (Serrien et al., 2006, 2007; Diedrichsen et al., 2007; Budde et al., 2008), and BDNF activity (Hung et al., 2013), all events that could have improved brain function and therefore cognitive functions. Various studies investigated neuroplasticity exercise-induced response of BDNF and its possible influence on cognitive functions, which could occur even approximately 30 min after exercise (Knaepen et al., 2010). The facilitation of cognitive functions following exercise was presumably attributable to brain alterations because of a cascade of molecular and cellular processes induced by acute exercise that support brain plasticity (Knaepen et al., 2010; Brunelli et al., 2012). BDNF could play a crucial role in these induced mechanisms. Human studies investigating the acute effects of single bouts of exercise reported transient elevations in BDNF levels (Hung et al., 2013; Schmolesky et al., 2013). This altered BDNF circulation after exercise could contribute to the development of a cortical environment that would be optimal for brain plasticity with a consequent enhanced neuroplasticity following acute exercise (Smith et al., 2014). Moreover, evidences suggest that testosterone could drive to structural changes of synapses and their associated dendritic spines after acute physical exercise (Devoogd et al., 1985) over a period of minutes to hours (Johansen-Berg et al., 2012). A rise in testosterone levels in our children could be another possible explanation of the facilitating effect of acute exercise on attentional performance in both physical activity groups. Our results are in line with results reported by Gabbard and Barton (1979) who assessed mathematical computation performance of second-grade children before and immediately after 20, 30, 40, and 50 min of acute vigorous physical activity. Children’s computation performance was significantly higher when observed 50′ after physical activity, supporting that acute exercise had a relatively long-lasting facilitative effect on executive function. Neuroelectric evidence demonstrated that acute bouts of exercise could increase attentional resource allocation and that this influence was substantial not only during exercise-induced arousal but also 30 min after the conclusion of exercise (Hung et al., 2013). Studies reported that exercise modality was a significant moderator of the exercise-cognition relation (Lambourne & Tomporowski, 2010; Hung et al., 2013) suggesting that both chronic (Chang et al., 2013) and acute exercise that involves greater coordinative and attentional demands may have a greater benefit on cognitive performance than aerobic exercise alone (Budde et al., 2008; Pesce et al., 2009). These authors postulated the existence of a possible link between coordinative exercise and cognitive functions. During acute exercise,
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Gallotta et al. specific brain regions were activated, inducing beneficial effects on cognitive functions following exercise. Specifically, the activation of the prefrontal cortex during movement of high complexity seemed to be the possible mechanism responsible of this relationship between acute exercise and cognition. Our study is not consistent with these results; in fact, the major increases of attention occurred immediately after and 50′ post CE and PE exertion type than CPE exertion type lesson. It is possible that the combination of mental and physical stimuli may have led to a limited improvement and maintenance of cognitive performance after the CPE lesson. Moreover, attentional capacity in our study was assessed in primary school children following a 50′ physical activity lesson while Budde et al. (2008) measured this capacity in adolescents after 10′ of coordinative exercises. Therefore, the long-time mental effort made to understand and perform the coordinative exercises could have prevented the improvements in the attentional capacity in our children. Our results are inconsistent with those of Pesce et al. (2009) who showed a significant increase on immediate and delayed recall memory in middle school students following a team games lesson. The different cognitive function assessed (attention capacity vs freerecall memory) and participants’ age (primary school students vs middle school students) may be the reason of the disparate findings. Our second hypothesis about the depletion of attentional capacity following mental operations (CE) was not confirmed. Our results revealed that the level of attention was higher at 0′ and 50′ after each exertion session rather than before intervention. Moreover, the analysis of the absolute variation (Δ) and the percentage of variation (Δ%) of all three cognitive variables revealed that CE exertion type led to a higher improvement of CP values over the time than two other exertion conditions (Fig. 2). This higher improvement could be explained by two different factors. Firstly, motivational factors, such as the individual interest and enjoyment in the lesson, and teacher’s encouragement, could have positively affected concentration performance, justifying this unexpected result (Davies, 1983). Secondly, as previous studies have already reported (Raviv & Low, 1990; Caterino & Polak, 1994), the improvement in concentration performance observed after classroom activities is due to the relative ease of transfer of perceptual set from an academic class to a pen-and-paper test such as the d2-test of attention (Raviv & Low, 1990; Budde et al., 2010a). Moreover, it is plausible to suppose that the increase in arousal level in our children could have affected both manual motor performance (Wegner et al., 2014) and attentional capacity inducing a better concentration performance as shown by Wegner et al. (2014) who found that acute psychosocial stress led to a significant increase of dexterity performance because of a moderate increase in arousal level.
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Overall, children of CE group showed the worst concentration performance. Finally, females obtained higher TN values than males. This pattern is similarly to other studies reporting females’ superiority in processing speed in several age groups (Barr, 2003). However, our results revealed that reported gender differences for TN values did not interact with both time and exertion type, so that these differences disappeared in the absolute and percentage variation of this variable. The lack of statistically significant differences in Δ%E% following all three experimental sessions suggested that the improvement in processing speed (TN) was not detrimental for the test accuracy thus refusing once again the teachers’ erroneous belief that physical exercise could produce a deterioration in quality of pupils’ attention and concentration performances. Overall, our results confirmed results of studies conducted on young adults reporting that arousal facilitates cognitive processes following exercise (Lambourne & Tomporowski, 2010). Therefore, exercise could improve the rapidity and the efficiency in performing cognitive tasks in children as well as in adults. However, since children’s HR was similar in both physical activity groups, we assume that the different character of the PE lessons might be responsible for the significant differences in attentional and concentration improvement. Limitations of the study result from the lack of assessment of further neuropsychological functions beyond performance on the d2 or the lack of a control group without any intervention that could limit the interpretation of the results.
Perspectives In conclusion, our findings suggest a medium to large size for the beneficial effect of different types of exertion on school children’s function of immediate and delayed attention. As expected, the heightened level of arousal following exercise facilitated attentional function. However, exercise mode/exertion type is a significant moderator since cognitive performance was affected differentially by exercise mode. Specific types of exercise may facilitate cognitive functioning more than others. Furthermore, given that several recent studies have established possible linkages between the type of exercise and cognition, further investigations are needed. The present work does not allow us to verify the mechanisms that induced the previously mentioned effects. Further research is needed to investigate the role of androgens concentration on children’s attentional performance in relation to different types of exertion. Key words: Physical activity, MVPA, immediate and delayed attention, school context.
Physical exertion and delayed attention Acknowledgements The authors are very grateful to the Primary School G.B. Basile and to all children involved in the study, as without them, this project could not be achieved. Additionally, we thank Giorgio Pes,
Serena Quartu, Sara Iazzoni, and David Bondì for the achievement of the project. This research was partially supported by funds from the Department of Health Sciences (year 2010 – Cod. 49/2010), University of Rome “Foro Italico,” Rome, Italy (main investigator, Maria Chiara Gallotta).
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Acute physical activity and delayed attention in primary school students M. C. Gallotta1*, G. P. Emerenziani1*, E. Franciosi1, M. Meucci2, L. Guidetti1†, C. Baldari1† Department of Movement, Human and Health Sciences, University of Rome “Foro Italico,” Rome, Italy, 2Department of Health and Exercise Science, Appalachian State University, Boone, North Carolina, USA Corresponding author: Carlo Baldari, University of Rome “Foro Italico,” Piazza Lauro De Bosis, 6, I-00135 Rome, Italy. Tel: 0039 06 36733227, Fax: 0039 06 36733211, E-mail: [email protected]
1
Accepted for publication 15 July 2014
To examine the influence of different types of exertion on immediate and delayed attention in 116 primary school children divided in three groups of exertion [cognitive exertion – CE (school curricular lesson), physical exertion – PE (traditional physical education lesson), mixed cognitive and physical exertion – CPE (coordinative physical education lesson)]. CPE was the combination of physical load due to the practice of physical exercises and of cognitive load requested to perform movement-based problem solving tasks requiring accurate timing, temporal estimations, temporal production, and spatial adjustments. Children’s attentional capacity was tested before (pre) and after (at 0 min and at 50 min post) a CE, a PE,
or a CPE lesson, using the d2-test of attention, and analyzed using a 3 × 3 × 2 mixed analysis of covariance with exertion type and time as within factors, gender as between factor, and baseline data as covariate. Effect sizes were calculated as partial eta squared (ƞ2). Results showed that participants’ attentional performance was significantly affected by exertion type (P < 0.0001), by time (P < 0.0001) and by exertion type × time interactions (P < 0.0001). The effect sizes ranged from medium (0.039) to large (0.437). Varying the type of exertion has different beneficial influences on the level of attention in school children.
School teachers often claim that pupils’ cognitive and academic performances were impaired after physical education classes. Therefore, numerous studies have been conducted to demonstrate the facilitating effect of physical exercise on cognitive functions (Raviv & Low, 1990; Pellegrini & Davis, 1993; Mahar et al., 2006; Budde et al., 2010b; Niemann et al., 2013). Recently, it has been shown that acute exercise can be beneficial for children’s mental functions (Tomporowski, 2003a; Tomporowski et al., 2011; Verburgh et al., 2014). However, the relationship between physical exercise and cognitive function is very complex since the improvement of children’s cognitive functions after acute exercise can depend on duration (McNaughten & Gabbard, 1993), intensity (Tomporowski, 2003a; Kamijo et al., 2007; Budde et al., 2010b), and specific type (Raviv & Low, 1990; Budde et al., 2008; Tomporowski et al., 2008; Pesce et al., 2009) of physical exercises performed during physical activity interventions. Moreover, acute exercise-induced modifications on cognitive performances are determined by the interactive effects between
acute and chronic exercise (Budde et al., 2012). Many studies revealed that acute physical exercises could induce beneficial effects on children’s and adolescents’ response speed and accuracy (Tomporowski, 2003b), memory (Pesce et al., 2009; Budde et al., 2010b), attention, and concentration capacity (Gallotta et al., 2012; Niemann et al., 2013) by positively influencing the physiological arousal (Lambourne & Tomporowski, 2010), changing brain neurochemistry (Ellemberg & St. Louis Deschenes, 2010), increasing steroid hormones’ concentration (Budde et al., 2010b) and cerebral blood flow (Tomporowski, 2003a; Ellemberg & St. Louis Deschenes, 2010), inducing an excitement of cerebellum and prefrontal cortex (Serrien et al., 2006, 2007; Diedrichsen et al., 2007; Budde et al., 2008), and brainderived neurotrophic factor (BDNF) activity (Hung et al., 2013). In school context, attention and concentration capacities assume an important role being key elements in the learning process (Zervas & Stambulova, 1999). Indeed, pupils often reduce their attention and concentration across school time for prolonged periods of academic instruction (Pellegrini & Davis, 1993; Budde et al., 2008) because of mental operations conducted in the process of learning in class (Raviv & Low, 1990). To investigate the possible role of exercise in the
*The contribution of these first two authors must be considered equal. † The contribution of these last two authors must be considered equal.
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Gallotta et al. school setting, researchers have investigated the effect of acute physical activity on cognitive abilities and memory (Budde et al., 2010b; Gallotta et al., 2012). However, few studies that investigated the possible influence of qualitative aspects of acute physical activity (type of physical activity) were conducted on children’s attentional performance (Budde et al., 2008; Gallotta et al., 2012; Niemann et al., 2013) even though the quality of motor experiences might contribute not only to physical and lifestyle development (Bailey, 2006; Fairclough et al., 2013), but also to cognitive development (Taras, 2005). Therefore, physical education could represent an essential instrument to offer children a quality experience of physical activity improving cognitive function and facilitating the learning process. The aim of this study was to examine the potential influence of different types of exertion on primary school children’s attentional duration (immediate and delayed attention) in three consecutive moments (before, immediately after, and after 50 min). We hypothesized that exercise-induced arousal following acute exercise could induce a consequent facilitation of attentional performance. This facilitation could probably be due to the activation of some specific neuronal structures common to cognition and movement coordination (Budde et al., 2008) or to a change in steroid hormones concentration after exercise which was observed both in children (Budde et al., 2010c) and adolescents (Budde et al., 2010a, b). According to the theoretical background, we investigated the possible role that different types of acute physical activity could have on immediate and delayed attention in primary school student’s comparing the level and quality of their attention immediately before (pre), immediately after (at 0 min post), and 50 min after three different types of school lessons. School lessons were a traditional physical education lesson, corresponding to physical exertion (PE), a coordinative physical education lesson, corresponding to a mixed cognitive and physical exertion (CPE), and a school curricular lesson, corresponding to cognitive exertion (CE). By proposing the same exercise intensity in both physical education lessons, according to the guidelines for school health physical activity programs to promote healthy behavior among children (Centers for Disease Control and Prevention, 1997), we hypothesized that their different qualitative type might induce significant differences on children’s attentional performance across time. In fact, while the heart rate (HR) was controlled to impose the same exercise intensity, the main difference between the two physical education lessons was induced by the manipulation of qualitative aspects of the physical activity intervention concerning the level and variety of coordinative demands of the teaching contents (Mechling, 1999). Specifically, PE was structured focusing on endurance exercises for cardiovascular health, while CPE was structured focusing on the high variability of motor coordination and skill learning demands.
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Materials and methods Study design The study was designed as a cluster-randomized controlled intervention in all classes (from grade 3 to grade 5) of a single primary school in Rome, Italy. The unit of randomization was the participating class. Nine classes with a total sample of 116 school children participated. The researcher randomized the nine classes into three groups of intervention. There were three classes in each intervention group.
Participants One hundred and sixteen school children aged between 8 and 11 years volunteered to participate in this study. The classes were two of grade 3 with a total of 36 children (8–9 years of age), three of grade 4 with a total of 26 children (9–10 years of age), and four of grade 5 with a total of 54 children (10–11 years of age), respectively. After cluster randomization, thirty-nine participants were in the cognitive exertion group (CE), 31 participants in the physical exertion group (PE), and the remaining 46 participants in the cognitive plus physical exertion group (CPE). Children were eligible if they had no learning and academic difficulties, attention-deficit disorders, neurological and developmental disorders, dyslexia, medical conditions that would affect study results or limit physical activity. The Institutional Review Board of the University of Rome “Foro Italico” approved this investigation. Written informed consent forms were obtained from both parents and children prior to study participation.
Procedures Each group participated in one of the three experimental sessions corresponding to a different type of exertion [cognitive (CE), physical (PE), cognitive plus physical exertion (CPE)]. Children completed the same attentional test before (pre) and after 0 min and 50 min (post) the experimental session. Experimental sessions occurred in the morning, at the same time of the school day. The CE consisted of a 50-min academic class about humanistic subject matters (Decree of the President of the Republic of Italy n. 254 of 16 November 2012, 2013). The PE and CPE were equivalent in structure, total duration (50 min) and intensity. Both lessons started with 15 min of warmup, followed with 30 min of continuous moderate to vigorous physical activities (MVPA), and ended with 5 min of cool-down and stretching. All children were equipped with HR monitors during both physical activity lessons. The exercise intensity of both lessons was monitored by recording HR using a HR monitor (S610i; Polar Electro Oy, Kempele, Finland) in order to establish exertion in the MVPA range of a HR > 139 bpm (Wang et al., 2005). At this purpose, we set HR target zones (MVPA) on the HR monitor prior to exercise: an alarm sounded if child’s HR was below the MVPA zone to control HR and maintain a continuous MVPA during all session avoiding differences between lessons (Fig. 1). The CE and CPE differed only in type of physical activities that children were engaged in. The PE consisted of continuous aerobic circuit training (Weineck, 2007) followed by a submaximal shuttle run exercise. This lesson was focused on the improvement of cardiovascular endurance by performing different types of gaits (e.g., fast walking, running, skipping) without any specific coordinative request (Decree of the President of the Republic of Italy n. 254 of 16 November 2012, 2013). The PE provided changes in executive modalities and some variations of intensity, but not rest periods. The CPE consisted of the sport-unspecific use of basketballs in the context of mini-games. The basketballs were used in
Physical exertion and delayed attention
Fig. 1. Individual graphs of HR during CPE and PE lessons. unconventional ways with varying game rules (e.g., use of footeye coordination techniques with basketballs; Gallotta et al., 2009; Gallotta, 2010). This lesson was geared toward the development of both motor control and perceptual-motor adaptation abilities. The high variability in the activities aimed to contribute to a multilateral development of coordinative abilities (Roth, 1982). This lesson was focused on the development of psychomotor competences and expertise in movement-based problem solving through functional use of a common tool (e.g., basketball), and considering various tasks that involved decision-making motor tasks and manipulative ball handling skills (e.g., bouncing, throwing, receiving a ball, and their combination). CPE resulted from the combination of physical load due to the practice of physical exercises and of cognitive load requested to perform movementbased problem solving and decision-making tasks requiring accurate timing, temporal estimations, temporal production, spatial and temporal adjustments, and spatial and temporal orientation that were essential parts of the cognitive requirements to perform such a kind of activities (Buscà et al., 2011). The CPE aimed to develop both motor control abilities and perceptual-motor adaptation abilities, by combining demands on gross-motor and manipulative control abilities and perceptual-motor adaptation abilities (particularly kinesthetic differentiation and response orientation). After completing the experimental session, participants moved quickly to the classroom to continue the scheduled school day attending a 50-min academic class.
Experimental measures Immediately, pre and post and 50 min post each exertion session, children completed the d2-test of attention (Brickenkamp & Zillmer, 1998) developed to measure sustained attention and concentration under stress induced by a completion time. The d2-test is a paper and pencil letter-cancellation test that consists of 14 different lines each one composed by 47 randomly mixed letters (p, d) with one to four single and/or double quotation marks either over and/or under each letter. Children were required to mark, within 20 s for each line, only the letters “d” that have double quotation marks either above or below them. The test lasted 4.67 min. Each child’s score was determined by the total number of items processed (TN) within the d2-test, by the number of letters correctly marked minus errors committed (CP) and by the percentage of errors (E%) made within all items processed. TN
was a measure of processing speed and amount of work completed, CP was a measure of concentration performance, and E% was a measure of performance quality. A low error rate indicated high-quality performance. The range of the test reliability was between 0.95 and 0.98 and the validity coefficient was 0.47 (Brickenkamp & Zillmer, 1998). The d2-test determines the capacity to focus on one stimulus/ fact, while suppressing awareness to competing distractors (Brickenkamp & Zillmer, 1998). Processes of selective attention are also required for successful completion since not only the letter “d” is orthographically similar to the letter “p,” but there are many distractor letters “d” with more than two dashes (Brickenkamp & Zillmer, 1998). The performance on this test reflects visual perceptual speed and concentrative capacities.
Statistical analysis All results were expressed as mean ± standard deviation. According to a previous study (Gallotta et al., 2012), individual scores (TN, E%, CP) were analyzed using a 3 × 3 × 2 mixed analysis of covariance with exertion type (CE vs PE vs CPE) and time (pre vs 0′ post vs 50′ post) as within factors, gender (male vs female) as between factor, and baseline data as covariate. Effect size was also calculate using Cohen’s definition of small, medium, and large effect size (as partial ƞ2 = 0.01, 0.06, 0.14). Significant interactions were further analyzed by means of Bonferroni post-hoc analysis. Within the gender factor, differences in the baseline attentional variable scores of males and females were verified using an analysis of variance (ANOVA) comparison. Moreover, for each attentional variable score evaluated after the intervention, we calculated the absolute variation (Δ) and the percentage of variation (Δ%) with respect to its pre-intervention value (0′ postintervention – pre-intervention value and 50′ post-intervention – pre-intervention value) for CE, PE, and CPE group, respectively. ANOVA for repeated measures was then performed to examine the effect of exertion type (CE vs PE vs CPE), gender (male vs female), and time on absolute variation (Δ) and on the percentage of variation (Δ%) in each attentional variable, followed by posthoc analysis (Bonferroni adjustment) to determine effects within the three exertion types. Significant differences between PE and CPE exercise intensity were verified by means of planned pairwise comparison (t-test). Statistical significance was defined as P ≤ 0.05.
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Exertion type Time Exertion type × time Gender Exertion type Time Exertion type × time Exertion type Time
10.44 49.26 25.48 6.29 42.35 4.43 3.42 13.18 12.41
2 2 4 1 2 2 4 2 2
< 0.0001 < 0.0001 < 0.0001 < 0.05 < 0.0001 < 0.01 = 0.01 < 0.0001 < 0.0001
0.161 0.311 0.319 0.055 0.437 0.039 0.059 0.195 0.102
E% CP
CP, number of letters correctly marked minus errors committed; E%, percentage of errors; TN, total number of items processed.
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457.65 ± 115.46 2.30 ± 2.75 193.93 ± 58.04* 443.85 ± 103.99‡ 1.85 ± 2.05 181.89 ± 45.28‡ 544.30 ± 83.45† 22.15 ± 2.17 119.53 ± 35.77† 510.43 ± 89.83* 22.86 ± 2.875 108.87 ± 38.25* 430.53 ± 106.86‡ 23.33 ± 2.33‡ 80.74 ± 31.26‡
50' post 0' post Pre 0' post
50' post
CPE
431.71 ± 67.14† 2.61 ± 4.13 170.71 ± 35.43†
50' post
*P ≤ 0.05 0' post vs pre. † P ≤ 0.05 50' post vs 0' post. ‡ P ≤ 0.05 50' post vs pre. CP, number of letters correctly marked minus errors committed; E%, percentage of errors; TN, total number of items processed.
TN
414.19 ± 70.50* 2.70 ± 4.34 162.81 ± 34.26*
Partial η2
355.06 ± 65.29‡ 2.77 ± 4.37 139.80 ± 31.04‡
P
TN E% CP
d.f.
Pre
F
0' post
Factors
Pre
Variable
CE
Table 1. Significant analysis of covariance results on attentional test scores
PE
Table 1 reports only significant results that are relevant for the present study: main effects of exertion type, time, gender, and exertion type × time interactions. Differences in the baseline attentional variable scores for each exertion type were verified (P < 0.0001). Moreover, differences in the baseline attentional variable scores of males and females were verified (P < 0.05), but no significant effects of gender were revealed. Children significantly improved their TN, CP, and E% individual values after intervention (P < 0.0001). Moreover, exertion type × time interaction indicates the likely presence of differential effects of the exertion type on TN and E% variables change after intervention. Females’ TN values were significantly higher than males’ TN values (474.21 ± 97.56 vs 436.51 ± 108.76 scores, respectively). Table 2 shows pre-, 0′ post-, and 50′ postintervention individual scores and indicates that children improved their performances from pre- to 0′ post-, and to 50′ post-intervention to a lower degree when exerted in CPE condition as compared with both CE and PE conditions. Improvement across intervention for all three groups was analyzed using absolute variation (Δ) and percentage of variation (Δ%). ANOVA revealed a significant main effect of exertion type on ΔTN (F2,113 = 35.65, P < 0.0001, η2 = 0.393) and on ΔCP (F1,113 = 8.15, P = 0.001, η2 = 0.129), a significant main effect of time on ΔTN (F1,113 = 37.49, P < 0.0001, η2 = 0.254), on ΔE% (F1,113 = 8.44, P < 0.01, η2 = 0.071) and on ΔCP (F2,113 = 10.91, P < 0.001, η2 = 0.090). Moreover, ANOVA revealed a significant main effect of exertion type on Δ%TN (F2,113 = 24.75, P < 0.0001, η2 = 0.310) and on Δ%CP (F2,113 = 18.67, P < 0.0001, η2 = 0.253), a significant main effect of time on Δ%TN (F1,113 = 41.53, P < 0.0001, η2 = 0.274) and on Δ%CP (F1,113 = 20.59, P < 0.0001, η2 = 0.158), and finally and exertion type × time interaction on Δ%CP (F2,113 = 4.82, P = 0.010, η2 = 0.081). These results revealed that CPE exertion type led to a lower improvement of CP values over the time than the two others exertion conditions (Fig. 2).
Table 2. Pre-, 0' post-, and 50' post-intervention individual scores (mean values ± standard deviation) for physical exertion (PE), cognitive exertion (CE), mixed cognitive, and physical exertion (CPE) group
Results
477.24 ± 99.43† 1.50 ± 1.60† 198.93 ± 47.50
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Physical exertion and delayed attention
Fig. 2. Percentage of variation (Δ%) of concentration performance (CP) (±SEM). *P < 0.05 0′ post – pre vs 50′ post – pre.
HR monitoring verified that both physical education lessons (PE and CPE) had similar exercise intensity (146.56 ± 14.09 and 147.25 ± 15.50 bpm, respectively). Discussion This study investigated the potential influence of different types of exertion on pupil’s attentional performance across time. In all three groups, TN and CP scores significantly changed over time with a large and medium effect size, respectively. Specifically, school children showed higher working speed and concentration scores at 0′ post and 50′ post each exertion session rather than at the beginning (Table 2). The improvements in performance that arose through practice and being more familiar with the test requirements should be considered. Westhoff and Dewald (1990) proved that performance in concentration tests could be improved through repetition, but practice effects did not transfer from one concentration test to another. However, the validity and reliability of the d2-test of attention was documented by a large volume of research, proving the high test-retest reliability of the test (Brickenkamp & Zillmer, 1998). However, because of the improvement of TN and CP scores over the time in all three groups, we cannot separate a general effect of acute exercise from a learning effect, which might interfere with the impact of the compounds on attention. Therefore, to exclude the influence of the learning effect on attentional performance across time, the learning effect was controlled using baseline data as covariate (Gallotta et al., 2012). Thus, our results showed a significant effect of exertion type on the attentional variables measured over time. We could speculate that our results support the hypothesis about the facilitation of attentional performance caused by maintenance of exercise-induced arousal following acute exercise. This facilitating effect could be the result of an increase in steroid hormones’ concentration (Budde et al., 2010b), changes in brain
neurochemistry (Ellemberg & St. Louis Deschenes, 2010), increase in cerebral blood flow (Tomporowski, 2003a; Ellemberg & St. Louis Deschenes, 2010), excitement of cerebellum and prefrontal cortex (Serrien et al., 2006, 2007; Diedrichsen et al., 2007; Budde et al., 2008), and BDNF activity (Hung et al., 2013), all events that could have improved brain function and therefore cognitive functions. Various studies investigated neuroplasticity exercise-induced response of BDNF and its possible influence on cognitive functions, which could occur even approximately 30 min after exercise (Knaepen et al., 2010). The facilitation of cognitive functions following exercise was presumably attributable to brain alterations because of a cascade of molecular and cellular processes induced by acute exercise that support brain plasticity (Knaepen et al., 2010; Brunelli et al., 2012). BDNF could play a crucial role in these induced mechanisms. Human studies investigating the acute effects of single bouts of exercise reported transient elevations in BDNF levels (Hung et al., 2013; Schmolesky et al., 2013). This altered BDNF circulation after exercise could contribute to the development of a cortical environment that would be optimal for brain plasticity with a consequent enhanced neuroplasticity following acute exercise (Smith et al., 2014). Moreover, evidences suggest that testosterone could drive to structural changes of synapses and their associated dendritic spines after acute physical exercise (Devoogd et al., 1985) over a period of minutes to hours (Johansen-Berg et al., 2012). A rise in testosterone levels in our children could be another possible explanation of the facilitating effect of acute exercise on attentional performance in both physical activity groups. Our results are in line with results reported by Gabbard and Barton (1979) who assessed mathematical computation performance of second-grade children before and immediately after 20, 30, 40, and 50 min of acute vigorous physical activity. Children’s computation performance was significantly higher when observed 50′ after physical activity, supporting that acute exercise had a relatively long-lasting facilitative effect on executive function. Neuroelectric evidence demonstrated that acute bouts of exercise could increase attentional resource allocation and that this influence was substantial not only during exercise-induced arousal but also 30 min after the conclusion of exercise (Hung et al., 2013). Studies reported that exercise modality was a significant moderator of the exercise-cognition relation (Lambourne & Tomporowski, 2010; Hung et al., 2013) suggesting that both chronic (Chang et al., 2013) and acute exercise that involves greater coordinative and attentional demands may have a greater benefit on cognitive performance than aerobic exercise alone (Budde et al., 2008; Pesce et al., 2009). These authors postulated the existence of a possible link between coordinative exercise and cognitive functions. During acute exercise,
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Gallotta et al. specific brain regions were activated, inducing beneficial effects on cognitive functions following exercise. Specifically, the activation of the prefrontal cortex during movement of high complexity seemed to be the possible mechanism responsible of this relationship between acute exercise and cognition. Our study is not consistent with these results; in fact, the major increases of attention occurred immediately after and 50′ post CE and PE exertion type than CPE exertion type lesson. It is possible that the combination of mental and physical stimuli may have led to a limited improvement and maintenance of cognitive performance after the CPE lesson. Moreover, attentional capacity in our study was assessed in primary school children following a 50′ physical activity lesson while Budde et al. (2008) measured this capacity in adolescents after 10′ of coordinative exercises. Therefore, the long-time mental effort made to understand and perform the coordinative exercises could have prevented the improvements in the attentional capacity in our children. Our results are inconsistent with those of Pesce et al. (2009) who showed a significant increase on immediate and delayed recall memory in middle school students following a team games lesson. The different cognitive function assessed (attention capacity vs freerecall memory) and participants’ age (primary school students vs middle school students) may be the reason of the disparate findings. Our second hypothesis about the depletion of attentional capacity following mental operations (CE) was not confirmed. Our results revealed that the level of attention was higher at 0′ and 50′ after each exertion session rather than before intervention. Moreover, the analysis of the absolute variation (Δ) and the percentage of variation (Δ%) of all three cognitive variables revealed that CE exertion type led to a higher improvement of CP values over the time than two other exertion conditions (Fig. 2). This higher improvement could be explained by two different factors. Firstly, motivational factors, such as the individual interest and enjoyment in the lesson, and teacher’s encouragement, could have positively affected concentration performance, justifying this unexpected result (Davies, 1983). Secondly, as previous studies have already reported (Raviv & Low, 1990; Caterino & Polak, 1994), the improvement in concentration performance observed after classroom activities is due to the relative ease of transfer of perceptual set from an academic class to a pen-and-paper test such as the d2-test of attention (Raviv & Low, 1990; Budde et al., 2010a). Moreover, it is plausible to suppose that the increase in arousal level in our children could have affected both manual motor performance (Wegner et al., 2014) and attentional capacity inducing a better concentration performance as shown by Wegner et al. (2014) who found that acute psychosocial stress led to a significant increase of dexterity performance because of a moderate increase in arousal level.
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Overall, children of CE group showed the worst concentration performance. Finally, females obtained higher TN values than males. This pattern is similarly to other studies reporting females’ superiority in processing speed in several age groups (Barr, 2003). However, our results revealed that reported gender differences for TN values did not interact with both time and exertion type, so that these differences disappeared in the absolute and percentage variation of this variable. The lack of statistically significant differences in Δ%E% following all three experimental sessions suggested that the improvement in processing speed (TN) was not detrimental for the test accuracy thus refusing once again the teachers’ erroneous belief that physical exercise could produce a deterioration in quality of pupils’ attention and concentration performances. Overall, our results confirmed results of studies conducted on young adults reporting that arousal facilitates cognitive processes following exercise (Lambourne & Tomporowski, 2010). Therefore, exercise could improve the rapidity and the efficiency in performing cognitive tasks in children as well as in adults. However, since children’s HR was similar in both physical activity groups, we assume that the different character of the PE lessons might be responsible for the significant differences in attentional and concentration improvement. Limitations of the study result from the lack of assessment of further neuropsychological functions beyond performance on the d2 or the lack of a control group without any intervention that could limit the interpretation of the results.
Perspectives In conclusion, our findings suggest a medium to large size for the beneficial effect of different types of exertion on school children’s function of immediate and delayed attention. As expected, the heightened level of arousal following exercise facilitated attentional function. However, exercise mode/exertion type is a significant moderator since cognitive performance was affected differentially by exercise mode. Specific types of exercise may facilitate cognitive functioning more than others. Furthermore, given that several recent studies have established possible linkages between the type of exercise and cognition, further investigations are needed. The present work does not allow us to verify the mechanisms that induced the previously mentioned effects. Further research is needed to investigate the role of androgens concentration on children’s attentional performance in relation to different types of exertion. Key words: Physical activity, MVPA, immediate and delayed attention, school context.
Physical exertion and delayed attention Acknowledgements The authors are very grateful to the Primary School G.B. Basile and to all children involved in the study, as without them, this project could not be achieved. Additionally, we thank Giorgio Pes,
Serena Quartu, Sara Iazzoni, and David Bondì for the achievement of the project. This research was partially supported by funds from the Department of Health Sciences (year 2010 – Cod. 49/2010), University of Rome “Foro Italico,” Rome, Italy (main investigator, Maria Chiara Gallotta).
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