Detrimental effects of prior self‐control exertion on subsequent sporting skill performance

The prior exertion of self-control has previously been shown to negatively affect physical performance, yet the effects on complex sporting skill performance have not been examined. Therefore, this study examined whether prior self-control exertion influences performance on a field hockey task, alongside measuring plasma cortisol concentration and attention as potential mechanisms to explain any effects. Following familiarization, 13 male hockey players (20 ± 1 years) participated in a randomized, order-balanced, crossover design. For the manipulation of self-control, participants completed an incongruent (self-control exertion trial) or a congruent (control trial) Stroop task. Skill performance was assessed using a field hockey skills task. Capillary blood samples, for the determination of plasma cortisol concentration, were taken at baseline, post-Stroop task, and post-field hockey skills task. Cognitive tests of attention (RVIP and Flanker tasks) were completed following the field hockey skills task. Participants made more errors in the latter stages of the field hockey skills task following self-control exertion (trial*time interaction, p = 0.041). Participants also made more errors on the RVIP task following self-control exertion (p = 0.035); yet the time taken to complete the hockey skills task, performance on the flanker task, and plasma cortisol concentrations were unaffected (all p > 0.05). Overall, these findings suggest that prior self-control exertion has detrimental effects on subsequent sporting skill performance (more errors made on the field hockey task), which may be explained by poorer sustained attention (lower accuracy on the RVIP task). This suggests that athletes should aim to avoid self-control exertion before a competitive match to optimize performance

Effect of exercise duration on postprandial glycaemic and insulinaemic responses in adolescents

High-intensity intermittent exercise (HIIE) is a potential intervention to manage hyperglycaemia and insulin resistance in adolescents. The aim of this study was to determine the optimum duration of HIIE to reduce postprandial glycaemic and insulinaemic responses in adolescents and the longevity of the response. Thirty-nine participants (12.4 ± 0.4 year) completed a 30- and 60-min exercise trial (Loughborough Intermittent Shuttle Test) and a rested control trial in a randomised crossover design. Capillary blood samples were taken at baseline, immediately and 1-h post-exercise; and 30, 60 and 120 min following a standardised lunch (day one) and a standardised breakfast 24-h post-exercise. Plasma insulin total area under the curve (tAUC) following lunch was lower following 60-min HIIE (21,754 ± 16,861 pmol·L−1 × 120 min, p = 0.032) and tended to be lower following 30-min HIIE (24,273 ± 16,131 pmol·L−1 × 120 min, p = 0.080), when compared with the resting condition (26,931 ± 21,634 pmol·L−1 × 120 min). Blood glucose concentration was lower 1-h post-exercise following 30-min HIIE (3.6 ± 0.6 mmol·L−1) when compared to resting (4.1 ± 0.9 mmol·L−1, p = 0.001). Blood glucose and plasma insulin concentration did not differ across trials on day two. Shorter bouts of HIIE (30-min), as well as a 60-min bout, reduced the postprandial insulinaemic response to lunch, an ecologically valid marker of insulin sensitivity. As the beneficial effects of HIIE were limited to 3 h post-exercise, adolescents are recommended to engage daily HIIE to enhance metabolic health

Predictors of postprandial glycaemia, insulinaemia and insulin resistance in adolescents

Postprandial glycaemia and insulinaemia are important risk factors for type 2 diabetes. The prevalence of insulin resistance in adolescents is increasing, but it is unknown how adolescent participant characteristics such as BMI, waist circumference, fitness and maturity offset may explain responses to a standard meal. The aim of the present study was to examine how such participant characteristics affect the postprandial glycaemic and insulinaemic responses to an ecologically valid mixed meal. Data from the control trials of three separate randomised, crossover experiments were pooled, resulting in a total of 108 participants (52 boys, 56 girls; age: 12.5±0.6 y; BMI: 19.05±2.66 kg·m-2). A fasting blood sample was taken for the calculation of fasting insulin resistance, using the HOMA-IR model. Further capillary blood samples were taken before and 30-, 60- and 120-min after a standardised lunch, providing 1.5 g.kg-1 body mass of carbohydrate, for the quantification of blood glucose and plasma insulin total area under the curve (tAUC). Hierarchical multiple linear regression demonstrated significant predictors for plasma insulin tAUC were waist circumference, physical fitness and HOMA-IR (F(3, 98)=36.78, p<.001, Adj. R2=.515). The variance in blood glucose tAUC was not significantly explained by the predictors used (F(7, 94)=1.44, p=.198). Significant predictors for HOMA-IR were BMI and maturity offset (F(2, 102)=14.06, p<.001, Adj. R2=.021). In summary, the key findings of the study are that waist circumference, followed by physical fitness, best explained the insulinemic response to an ecologically valid standardised meal in adolescents. This has important behavioural consequences because these variables can be modified

Effect of football activity and physical fitness on information processing, inhibitory control and working memory in adolescents

Background: Whilst an acute bout of exercise has been shown to enhance subsequent cognition, including in adolescents, the effects of team games (of which Football is the most popular) has received little attention. Therefore, this study examined: the effect of an acute bout of outdoor Football activity on information processing, inhibitory control, working memory and circulating brain-derived neurotrophic factor (BDNF) in adolescents; the effect of physical fitness on cognition and; the moderating effect of physical fitness on the acute exercise responses. Methods: Following familiarisation, 36 adolescents (16 girls) took part in two trials (60-min Football and 60-min seated rest) separated by 7-d in a counterbalanced, crossover design. Information processing and inhibitory control (Stroop Test), and working memory (Sternberg Paradigm) were assessed 30-min before exercise/rest and immediately, 45- and 90-min post-exercise/rest. Capillary blood samples were obtained before exercise/rest and up to 120-min post-exercise/rest. The median split of distance covered on the MSFT was used to divide the group into high- and low-fit groups. Results: Performance on the cognitive function tasks was similar between Football and seated rest (trial*time interactions; all p > .05). However, the high-fit group had overall quicker response times on both levels of the Stroop Task and all three levels of the Sternberg Paradigm (main effect of fitness; all p  .05). Conclusion: The present study shows that higher levels of physical fitness are beneficial for cognitive function and provides novel evidence that an ecologically valid, and popular, form of exercise is beneficial for working memory following exercise, in high-fit participants only

Activity patterns of primary school children during participation in The Daily Mile

The Daily Mile is a popular physical activity initiative in primary schools, yet little is known regarding the activity patterns of children during The Daily Mile. Eighty children (10.4 ± 0.7 years) participated in The Daily Mile (20-min). Activity patterns were assessed using global positioning systems (total distance and age-specific speed zones), alongside heart rate. Cardiorespiratory fitness was assessed using the Multi-Stage Fitness Test. Participants covered a distance of 2511 ± 550 m during The Daily Mile, and heart rate was 163 ± 27 beats.min−1. Participants travelled the furthest distance, and were most intermittent, during the first 5 min (main effect of time, both p < 0.001). Boys ran further and their activity was more intermittent compared to girls (main effect of sex, both p < 0.001). Moreover, the highest fit children ran further than less fit children (main effect of fitness, p < 0.001). This study provides novel evidence of the nature of physical activity during The Daily Mile; demonstrating that children covered, on average, 1.5-miles and exercised at a moderate-to-vigorous intensity. Furthermore, boys covered a greater distance and were more intermittent than girls; whilst higher fit children ran further than lower fit children. In summary, The Daily Mile makes a valuable contribution to in-school physical activity targets in all children

Effect of differing durations of high-intensity intermittent activity on cognitive function in adolescents

Exercise duration may influence the acute effects on cognition. However, only one study to date has explored the dose-response relationship between exercise duration and cognition in adolescents. Thus, the purpose of this study was to investigate the effect of differing durations of high-intensity intermittent running on cognition in adolescents. Thirty-eight adolescents (23 girls) completed three trials separated by 7 d: 30 min exercise, 60 min exercise, and rest; in a randomised crossover design. The exercise was a modified version of the Loughborough Intermittent Shuttle Test (LIST), which elicited high-intensity intermittent exercise. Cognitive function tests (Stroop test, Sternberg paradigm, Flanker task) were completed 30 min pre, immediately post, and 45 min post exercise. Response times on the incongruent level of the Flanker task improved to a greater extent 45 min following the 30 min LIST, compared to rest (p = 0.009). Moreover, response times improved to a greater extent on the three-item level of Sternberg paradigm 45 min following the 30 min LIST, compared to the 60 min LIST (p = 0.002) and rest (p = 0.013), as well as on the five-item level 45 min following the 30 min LIST, compared to the 60 min LIST (p = 0.002). In conclusion, acute exercise enhanced subsequent cognition in adolescents, but overall, 30 min of high-intensity intermittent running is more favourable to adolescents’ cognition, compared to 60 min

Cytokine, glycemic and insulinemic responses to an acute bout of games-based activity in adolescents

An acute bout of endurance exercise in adults stimulates a same‐day anti‐inflammatory response which may affect low‐grade chronic inflammation and insulin resistance and benefit cardio‐metabolic health. The anti‐inflammatory responses to intermittent games‐based exercise and to exercise in young people beyond 2‐h post‐exercise are unknown. Thus, the purpose of the present study is to examine the anti‐inflammatory, glycemic and insulinemic response to games‐based activity in adolescents. Following ethical approval and familiarization, 39 adolescents (12.3±0.7 y) completed an exercise (E) and rested (R) trial in a counterbalanced, randomized crossover design. Following a standardized breakfast, participants completed 1‐h games‐based activity. Capillary blood samples were taken at baseline, immediately and 1‐h post‐exercise and 30, 60 and 120‐min following a standardized lunch. A final blood sample was taken the next morning. Data were analyzed using repeated measures ANOVA. IL‐6 concentration was higher on day one of the exercise trial (E:3.4±0.4, R:2.7±0.4 pg.mL−1; p=0.006), as was the anti‐inflammatory IL‐6:TNF‐α ratio (E:5.53±0.93, R:3.75±0.45; p=0.027). Levels of the anti‐inflammatory cytokine IL‐10 increased on day two of the exercise trial (E:2.11±0.23, R:1.66±0.16 pg.mL−1; p=0.032). Insulin sensitivity was enhanced on the exercise trial with a reduction in iAUC following the standardized lunch (E:2310±834, R:3122±1443 mU.L−1x120 min; p<0.001). Games‐based activity stimulated an anti‐inflammatory response up to 24 h post‐exercise and improved insulin sensitivity in response to a standardized meal in healthy adolescents. These novel findings suggest that games‐based activity is an ecologically valid mode of exercise to elicit beneficial effects on cardio‐metabolic risk factors in young people

Multi-stage fitness test performance, V˙O2 peak and adiposity: effect on risk factors for cardio-metabolic disease in adolescents

The role of physical activity in determining the metabolic health of adolescents is poorly understood, particularly concerning the effect on low-grade chronic inflammation (chronic elevation of pro-inflammatory cytokines IL-1β, IL-6, TNF-α and acute phase protein CRP, which is implicated in the etiology of atherosclerosis) and anti-inflammatory mediators such as IL-10. Furthermore, there is limited information on the mediating effects of performance on the multi-stage fitness test (MSFT), V˙O2 peak and adiposity on risk factors for cardio-metabolic disease in adolescents. Purpose: To examine the effect of performance on the MSFT, V˙O2 peak and adiposity on risk factors for cardio-metabolic diseases in adolescents. Methods: Following ethical approval, 121 adolescents (11.3 ± 0.8 year) completed the study. Risk factors for cardio-metabolic disease (circulating inflammatory cytokines, blood glucose and plasma insulin concentrations) was assessed using a fasted capillary blood sample. Participants were separated into quartiles based upon distance ran during the MSFT, the blood lactate response to submaximal exercise, V˙O2 peak (determined during an uphill graded treadmill test), and adiposity (determined as the sum of four skinfolds). The blood lactate response to submaximal exercise and V02 peak were measured in a sub-group of participants. Data were analyzed using two-way between-subjects ANCOVA and multiple linear regression. Results: Participants with the lowest performance on the MSFT had higher blood concentrations of IL-6 (3.25 ± 0.25 pg mL-1) and IL-1β (4.78 ± 0.54 pg mL-1) and lower concentrations of IL-10 (1.80 ± 0.27 pg mL-1) when compared with all other quartiles (all p 0.05). Performance on the MSFT was the only predictor of IL-6 (β = -0.291, p = 0.031), IL-1β (β = -0.405, p = 0.005), IL-10 (β = 0.325, p = 0.021) and fasted blood glucose (β = -0.545, p < 0.001) concentrations. Adiposity was the only predictor of plasma insulin concentration (β = 0.515, p < 0.001) and blood pressure (diastolic: β = 0.259, p = 0.042; mean arterial pressure: β = 0.322, p = 0.011). Conclusion: Enhanced performance on the MSFT, but not V˙O2 peak, was associated with a favorable inflammatory profile in adolescents; whilst adiposity adversely affected plasma insulin, diastolic and mean arterial blood pressure. These findings demonstrate that enhancing performance on the MSFT and maintaining a healthy body composition are a potential therapeutic intervention for the attenuation of risk factors for cardio-metabolic diseases in adolescents

The Daily Mile™: acute effects on children’s cognitive function and factors affecting their enjoyment

The Daily Mile™ is a widely implemented school-based physical activity initiative. However, only two studies have explored the acute effects of participation in The Daily Mile on children’s cognitive functioning, reporting conflicting findings. Moreover, enjoyment of exercise is a determining factor in children’s motivation for, and adherence to, initiatives. However, factors affecting children’s enjoyment of The Daily Mile are unknown. Therefore, this study examined the acute effects of The Daily Mile on cognition and explored children’s enjoyment of participation in the initiative. Following familiarisation, 104 children (10.4 ± 0.7 years) completed a Daily Mile and resting control trial in a randomised, counterbalanced order. Prior to, immediately following and 45 min following The Daily Mile and resting, children completed the Stroop test (inhibitory control), Sternberg paradigm (visual working memory) and Flanker task (inhibitory control and cognitive flexibility). Additionally, 87 children took part in focus groups to explore factors affecting enjoyment. Cognitive data were analysed using two-way (trial*time) and three-way (trial*time*sex; trial*time*fitness) repeated measures analysis of variance (ANOVA). Focus group data were analysed using qualitative content analysis. There were no statistically significant effects of The Daily Mile on cognition, compared to rest (all p > 0.05). However, accuracy on the one-item level of Sternberg paradigm (p = 0.073, ηp2 = 0.028) and complex level of the Stroop test (p = 0.057; ηp2 = 0.031) tended to improve immediately following The Daily Mile, compared to resting; though this did not reach statistical significance. Children enjoyed participating in The Daily Mile, particularly due to its outdoor location, social context, and self-paced nature. However, some children found The Daily Mile boring due to its repetitive nature. Findings suggest that The Daily Mile does not significantly influence children’s immediate or delayed (45 min) cognition. However, there was a tendency for improved accuracy in visual working memory and inhibitory control immediately following The Daily Mile. Moreover, the findings demonstrate that The Daily Mile promotes enjoyment, particularly through social relatedness and autonomy. However, future research could consider whether adding variety into the initiative may help to sustain engagement in the children experiencing boredom

Effect of adiposity and physical fitness on cardiometabolic risk factors in adolescents: a 2-year longitudinal study

Although risk factors for cardiometabolic diseases begin to present in young people, the association between physical fitness and adiposity with traditional and novel risk factors for cardiometabolic diseases across adolescence remains relatively unknown. Following ethical approval, fifty-two adolescents (age 11.6 ± 0.6 years; 32 girls) were recruited for a 2-years longitudinal study. Adiposity was assessed based on sum of skinfolds, waist circumference and body mass index, and physical fitness as distance run on the multi-stage fitness test (MSFT). Risk factors for cardiometabolic diseases (pro- and anti-inflammatory cytokines, plasma insulin, Homeostatic Model Assessment of Insulin Resistance - HOMA-IR, blood pressure) were measured following an overnight fast. Relationships between independent and response variables were analysed using multi-level modelling (final combined models were created using the stepwise backward elimination method). Plasma insulin concentration and HOMA-IR were positively associated with adiposity and inversely associated with distance run on the MSFT (all p < 0.05). The final combined models for plasma insulin concentration and HOMA-IR contained main effects for age, skinfolds and distance run on the MSFT. Levels of the anti-inflammatory cytokine IL-10 were inversely related to the sum of skinfolds (p = 0.046), whereas there was a trend for levels of the pro-inflammatory cytokine TNF-α to be positively related to the sum of skinfolds (p = 0.056). Adiposity and physical fitness are important, independent, determinants of metabolic health in adolescents. Furthermore, adiposity influences levels of pro- and anti-inflammatory cytokines in adolescence, with greater adiposity associated with a poorer inflammatory profile. The present study demonstrates an independent effect of physical fitness on metabolic health longitudinally across adolescence. It is therefore recommended that future work develops therapeutic interventions that reduce adiposity and enhance physical fitness in adolescents, to promote lifelong health