Lower-fit Children Research Articles

Cardiorespiratory Fitness and the Flexible Modulation of Cognitive Control in Preadolescent Children

The influence of cardiorespiratory fitness on the modulation of cognitive control was assessed in preadolescent children separated into higher- and lower-fit groups. Participants completed compatible and incompatible stimulus-response conditions of a modified flanker task, consisting of congruent and incongruent arrays, while ERPs and task performance were concurrently measured. Findings revealed decreased response accuracy for lower- relative to higher-fit participants with a selectively larger deficit in response to the incompatible stimulus-response condition, requiring the greatest amount of cognitive control. In contrast, higher-fit participants maintained response accuracy across stimulus-response compatibility conditions. Neuroelectric measures indicated that higher-fit, relative to lower-fit, participants exhibited global increases in P3 amplitude and shorter P3 latency, as well as greater modulation of P3 amplitude between the compatible and incompatible stimulus-response conditions. Similarly, higher-fit participants exhibited smaller error-related negativity (ERN) amplitudes in the compatible condition, and greater modulation of the ERN between the compatible and incompatible conditions, relative to lower-fit participants who exhibited large ERN amplitudes across both conditions. These findings suggest that lower-fit children may have more difficulty than higher-fit children in the flexible modulation of cognitive control processes to meet task demands.

Aerobic Fitness and Executive Control of Relational Memory in Preadolescent Children

the neurocognitive benefits of an active lifestyle in childhood have public health and educational implications, especially as children in today's technological society are becoming increasingly overweight, unhealthy, and unfit. Human and animal studies show that aerobic exercise affects both prefrontal executive control and hippocampal function. This investigation attempts to bridge these research threads by using a cognitive task to examine the relationship between aerobic fitness and executive control of relational memory in preadolescent 9- and 10-yr-old children. higher-fit and lower-fit children studied faces and houses under individual item (i.e., nonrelational) and relational encoding conditions, and the children were subsequently tested with recognition memory trials consisting of previously studied pairs and pairs of completely new items. With each subject participating in both item and relational encoding conditions, and with recognition test trials amenable to the use of both item and relational memory cues, this task afforded a challenge to the flexible use of memory, specifically in the use of appropriate encoding and retrieval strategies. Hence, the task provided a test of both executive control and memory processes. lower-fit children showed poorer recognition memory performance than higher-fit children, selectively in the relational encoding condition. No association between aerobic fitness and recognition performance was found for faces and houses studied as individual items (i.e., nonrelationally). the findings implicate childhood aerobic fitness as a factor in the ability to use effective encoding and retrieval executive control processes for relational memory material and, possibly, in the strategic engagement of prefrontal- and hippocampal-dependent systems.

A neuroimaging investigation of the association between aerobic fitness, hippocampal volume, and memory performance in preadolescent children

Because children are becoming overweight, unhealthy, and unfit, understanding the neurocognitive benefits of an active lifestyle in childhood has important public health and educational implications. Animal research has indicated that aerobic exercise is related to increased cell proliferation and survival in the hippocampus as well as enhanced hippocampal-dependent learning and memory. Recent evidence extends this relationship to elderly humans by suggesting that high aerobic fitness levels in older adults are associated with increased hippocampal volume and superior memory performance. The present study aimed to further extend the link between fitness, hippocampal volume, and memory to a sample of preadolescent children. To this end, magnetic resonance imaging was employed to investigate whether higher- and lower-fit 9- and 10-year-old children showed differences in hippocampal volume and if the differences were related to performance on an item and relational memory task. Relational but not item memory is primarily supported by the hippocampus. Consistent with predictions, higher-fit children showed greater bilateral hippocampal volumes and superior relational memory task performance compared to lower-fit children. Hippocampal volume was also positively associated with performance on the relational but not the item memory task. Furthermore, bilateral hippocampal volume was found to mediate the relationship between fitness level (VO2 max) and relational memory. No relationship between aerobic fitness, nucleus accumbens volume, and memory was reported, which strengthens the hypothesized specific effect of fitness on the hippocampus. The findings are the first to indicate that aerobic fitness may relate to the structure and function of the preadolescent human brain.

Basal Ganglia Volume Is Associated with Aerobic Fitness in Preadolescent Children

The present investigation is the first to explore the association between childhood aerobic fitness and basal ganglia structure and function. Rodent research has revealed that exercise influences the striatum by increasing dopamine signaling and angiogenesis. In children, higher aerobic fitness levels are associated with greater hippocampal volumes, superior performance on tasks of attentional and interference control, and elevated event-related brain potential indices of executive function. The present study used magnetic resonance imaging to investigate if higher-fit and lower-fit 9- and 10-year-old children exhibited differential volumes of other subcortical brain regions, specifically the basal ganglia involved in attentional control. The relationship between aerobic fitness, dorsal and ventral striatum volumes and performance on an attention and inhibition Eriksen flanker task was also examined. The results indicated that higher-fit children showed superior flanker task performance compared to lower-fit children. Higher-fit children also showed greater volumes of the dorsal striatum, and dorsal striatum volume was negatively associated with behavioral interference. The results support the claim that the dorsal striatum is involved in cognitive control and response resolution and that these cognitive processes vary as a function of aerobic fitness. No relationship was found between aerobic fitness, the volume of the ventral striatum and flanker performance. The findings suggest that increased childhood aerobic fitness is associated with greater dorsal striatal volumes and that this is related to enhanced cognitive control. Because children are becoming increasingly overweight, unhealthy and unfit, understanding the neurocognitive benefits of an active lifestyle during childhood has important public health and educational implications.

Cognitive Performance in High and Low Fit Children

Cognitive Performance in High and Low Fit Children

Aerobic fitness and cognitive development: Event-related brain potential and task performance indices of executive control in preadolescent children.

The relationship between aerobic fitness and executive control was assessed in 38 higher- and lower-fit children (M-sub(age) = 9.4 years), grouped according to their performance on a field test of aerobic capacity. Participants performed a flanker task requiring variable amounts of executive control while event-related brain potential responses and task performance were assessed. Results indicated that higher-fit children performed more accurately across conditions of the flanker task and following commission errors when compared to lower-fit children, whereas no group differences were observed for reaction time. Neuroelectric data indicated that P3 amplitude was larger for higher- compared to lower-fit children across conditions of the flanker task, and higher-fit children exhibited reduced error-related negativity amplitude and increased error positivity amplitude compared to lower-fit children. The data suggest that fitness is associated with better cognitive performance on an executive control task through increased cognitive control, resulting in greater allocation of attentional resources during stimulus encoding and a subsequent reduction in conflict during response selection. The findings differ from those observed in adult populations by indicating a general rather than a selective relationship between aerobic fitness and cognition.

Cardiovascular fitness modifies the associations between physical activity and abdominal adiposity in children and adolescents: the European Youth Heart Study

ObjectiveTo examine the associations between physical activity (PA) and abdominal adiposity, as measured by waist circumference, in children and adolescents, and to test whether cardiovascular fitness (CVF) modifies these associations.MethodsPA...

The Relation of Fatness to Insulin is Independent of Fitness in 9- but Not 15-yr-olds

To explore the relationship between varying aerobic fitness (fitness), fatness, and fasting insulin levels in healthy children. A population-based sample of 9-yr-old (9YO, 47 boys, 56 girls) and 15-yr-old (15YO, 53 boys, 51 girls) Icelandic children. Body fatness was evaluated via body mass index, waist circumference adjusted for height (waist adj), and sum of four skinfolds. Fitness was assessed with a graded maximal cycle ergometer test. Fasting insulin was measured using an ECLIA. Fasting insulin correlated to all fatness measures (9YO, r = 0.43-0.46, P < 0.001; 15YO, r = 0.30-0.37, P < 0.003) and fitness (9YO, r = -0.29, P = 0.003; 15YO, r = -0.32, P = 0.001). Adjustment for fitness did not affect the relations between fatness and fasting insulin in 9YO (r = 0.33-0.37, P < 0.001); however, only waist adj remained significantly related to fasting insulin (r = 0.24, P = 0.016) in 15YO. Children in the upper half of fitness and fatness split on the median did not differ in fasting insulin from children in the upper half of fitness but lower half of fatness. Fatness was related to fasting insulin in 9YO (r = 0.51-0.54, P = 0.001) and 15YO (r = 0.31-0.35, P = 0.011-0.028) in the lower half of fitness, but no association was observed in the upper half of fitness in either group. Fatness has a greater association with fasting insulin than fitness, especially among 9YO; however, fitness attenuates the adverse relation of fatness to fasting insulin in 15YO but does not change it in 9YO. In both age groups, being fitter and fatter does not result in greater fasting insulin than being fitter and leaner, and fatness is primarily associated with fasting insulin in lower-fit children.

Development of 30-Minute Walking Test Standards for Lower-Fit Children and Adolescents

Previous research has established valid models for determining the energy cost of walking and running, but there are no appropriate criterion standards for a walking test of aerobic fitness for low-fit children that is consistent with ACSM guidelines. Current recommendations prescribe an intensity of at least 50%VO2max. PURPOSE: The purpose of this study was to develop a generalized model for determining the energy cost of walking and develop standards for a 30-minute walking test that might be appropriate for lower-fit children and adolescents to achieve 50% to 60%VO2max. METHODS: Subjects were 101 boy and 79 girl volunteers, ages 9–18 years. Each subject performed a submaximal treadmill exercise test at randomly selected walking and running speeds from 2–8 mph. VO2 was measured by open-circuit spirometry. The sample was randomly divided into a derivation sample of 90 subjects, and a cross-validation sample of 90 subjects. Multiple regression was used to develop models for estimating VO2 (ml.kg-1.min-1) in the derivation sample. RESULTS: The relationship between running speed and VO2 was linear, and the relationship between walking speed and VO2 was curvilinear. The derived equation is: VO2 (ml.kg-1.min-1) = 6.54 + 6.69(mph) - 5.78(mph x walk=1,run=0) + 1.23(mph x walk=1,run=0)2, R2 = .87, SEE = 4.0 ml.kg-1.min-1. Cross-validation revealed very little shrinkage in the derived model (R2 = .86, Error = 4.1 ml.kg-1.min-1). CONCLUSION: Using the derived model, predicted values of 50% to 60%VO2max for children and adolescents whose VO2max values are as low as 12 ml.kg-1.min-1 requires walking speeds between 2.0 and 2.15 mph. Consequently, a 30-minute walk at this relative intensity would require a distance of 1.0 to 1.1 miles. Predicted values of 50% to 60%VO2max for children and adolescents whose VO2max values are 39 ml.kg-1.min-1 requires walking speeds between 3.6 and 3.9 mph. Consequently, a 30-minute walk at this relative intensity would require a distance of 1.8 to 1.95 miles. These data demonstrate that the minimum ACSM requirements for intensity of aerobic exercise can be achieved by a 30-minute walking test of aerobic fitness in children and adolescents.

The Relationship of Aerobic Fitness to Interference Control in Preadolescent Children

Physical inactivity during childhood has steadily increased in recent years, leading to an increased prevalence of being overweight and unfit. Despite a growing body of literature indicating that physical activity may ameliorate or protect against decrements in cognitive performance during adulthood, the relationship between physical inactivity and decrements in cognitive health in children remains absent from public health concerns. PURPOSE: To investigate the relationship between aerobic fitness and executive control cognitive function using a task requiring variable amounts of interference control. METHODS: Forty-eight preadolescent children (Mage = 9.3 yrs) were grouped (i.e., higher-fit, lower-fit) according to their performance on a field test of aerobic capacity using the PACER test of the Fitnessgram, while other demographic variables (e.g., Age, SES, IQ) did not differ between fitness groups. Interference control was measured by event-related brain potential (ERPs) responses and task performance (reaction time, response accuracy) to congruent (e.g., HHHHH) and incongruent (e.g., HHSHH) conditions of an Eriksen flanker task. RESULTS: Results indicated that higher-fit children performed more accurately across conditions of the flanker task when compared to lower-fit children, while group-differences were not observed for reaction time latency. Further, P1 and P3 component amplitudes of the stimulus-locked ERP were larger for higher- compared to lower-fit children across conditions of the flanker task indicating that fitness may be associated with early visual attention processes as well as the allocation of attentional resources to working memory in the stimulus environment. CONCLUSION: The findings indicate that aerobic fitness may non-selectively benefit cognitive function on tasks requiring variable amounts of interference control during preadolescent childhood, and suggest that fitness may relate to improved cognitive health.

Aerobic Fitness and Neurocognitive Function in Healthy Preadolescent Children

We investigated the relationship between age, aerobic fitness, and cognitive function by comparing high- and low-fit preadolescent children and adults. Twenty-four children (mean age = 9.6 yr) and 27 adults (mean age = 19.3 yr) were grouped according to their fitness (high, low) such that four approximately equal groups were compared. Fitness was assessed using the Fitnessgram test, and cognitive function was measured by neuroelectric and behavioral responses to a stimulus discrimination task. Adults exhibited greater P3 amplitude at Cz and Pz sites, and decreased amplitude at the Oz site compared with children. High-fit children had greater P3 amplitude compared with low-fit children and high- and low-fit adults. Further, adults had faster P3 latency compared with children, and high-fit participants had faster P3 latency compared with low-fit participants at the Oz site. Adults exhibited faster reaction time than children; however, fitness interacted with age such that high-fit children had faster reaction time than low-fit children. These findings suggest that fitness was positively associated with neuroelectric indices of attention and working memory, and response speed in children. Fitness was also associated with cognitive processing speed, but these findings were not age-specific. These data indicate that fitness may be related to better cognitive functioning in preadolescents and have implications for increasing cognitive health in children and adults.