Effects of physical exercise on executive function and attention in children with ADHD
Acute physical exercise
A previous study, not included in the present analysis, found that acute exercise interventions improve executive function and attention in children with ADHD[15]. For example, they found that aerobic running or cycling improves cognitive performance in children with ADHD. In an RCT included in present analysis that subjected 23 children with ADHD to an aerobic exercise intervention, after 30 min of sustained moderate-intensity stationary cycling, the children showed improved attention processing speed reaction time and executive function, indicating that children with ADHD can benefit from a single session of acute aerobic exercise[16]. Another previous study, not included in the present analysis also showed that 20 min of acute physical activity training at moderate intensity on a treadmill improved neurocognitive function, inhibitory control, reading, and mathematics performance among children with ADHD[17]. Their findings are consistent with those of the study by Ludyga et al assessed in the present analysis, that found that a single acute 20 min session of moderate-intensity cycling was effective in improving inhibitory control and attentional resource allocation in children with ADHD[18]. Thus, aerobic running or cycling improves executive function and attention in children with ADHD, and the health benefits of acute moderate intensity aerobic exercise for children with ADHD, in particular, have been shown in several studies[19-20]. In the future, the use of aerobic endurance interventions should become common and routine for improving executive function and attention in children with ADHD. Additional physical health benefits of aerobic fitness exercise in children with ADHD should be explored, as obesity is also a common problem among children with ADHD[21].
Long-term physical exercise
In a 12-week yoga class intervention with a 30-min twice weekly program children with ADHD displayed reduced inattentive behavior and ADHD symptoms, indicating that yoga classes improved attention, visual-motor accuracy, and behavior in children with ADHD[22]. Previous studies have also demonstrated that a similar yoga intervention (60 min twice/wk) over an 8-week period significantly improved attention and reduced ADHD symptoms in children with ADHD [23]. However, in a study by Jensen et al., no significant changes in attention were detected after 20 sessions of yoga training for 11 boys with ADHD in the same program intervention over a 20-week period. The yoga group showed only small benefits in terms of parents’ ratings of ADHD symptoms after the intervention. However, the quality and duration of practice at home was not determined, and it is plausible that the emotional impact fluctuated, affecting experimental data collection[24].
Children with ADHD showed improved response sensitivity after a 12-week cycling intervention, and long-term aerobic exercise was effective in improving the core symptoms of poor attention, hyperactivity, and executive function in children with ADHD[22,25]. In a swimming exercise intervention program, 30 children with ADHD were assigned to an exercise group and a control group[26]. After 8 weeks of exercise intervention (90 min, twice/wk), Go/No-go tasks and motor skills were assessed. Significant improvements were found in accuracy related to no-go stimulation and motor skills coordination in the exercise group compared with the control group.
In summary, prolonged regular exercise interventions have a positive impact on improving attention and executive function hyperactivity in ADHD, and longer intervention durations appear to produce better intervention outcomes. However, owing to the differences in the types of long-term exercise interventions, the tests used to measure cognitive function, and biases in the diagnostic criteria for ADHD co-morbidities, further research is needed to elucidate the effects of these specific interventions in sufficiently large samples and to validate their effectiveness using standardized measures[27].
Effects of integrated movement on executive function and attention in children with ADHD
Acute integrated exercise
Using a comprehensive intervention program (high or low intensity) for children with ADHD at a summer camp program, one study found that daily measurements of mood, behavior, and learning efficiency before and after the activity showed no differences in learning efficiency between children with vs[28]. without ADHD after either the low-or high-intensity exercise interventions. However, there were differences in behavior and mood for the high-intensity exercise conditions. Compared with healthy children, children with ADHD experienced a wider range of behavioral problems and showed worse initial mood and more negative mood changes immediately after the high intensity exercise. In an RCT using high-intensity interval training (HIIT)[29], a 20-min high-intensity intervention (90% heart rate peak) was administered to 21 children with ADHD (11.3±1.8 y), and the Connor Continuous Performance Test was administered before and immediately after intervals of exercise. Significantly higher reaction time scores were found for children with ADHD compared with children without ADHD. In addition, in a similar study using a combination of HIIT and standard multi-modal therapy interventions, both interventions improved physical health, motor skills, quality of life, and attention in children with ADHD[30]. A systematic review has shown that the use of multidimensional behavior therapies, such as tai chi or yoga, integrated into light to moderate aerobic physical activity, with a focus on deep breathing and balance in short-term practice, can modify symptoms, reduce stress, and regulate emotional responses in children with ADHD[31].
In summary, acute medium-to high-intensity combined exercise of no less than 20 min in a single session improve executive function and attention in children with ADHD.
Long-term integrated exercise
A 20-week group therapy program based on an integrated movement intervention, which included individual physical activities, such as team games combined with behavior training (90 min/wk), improved the behavior of children with ADHD after the intervention[32]. Pan et al. combined a simulated horse-riding program with fitness training in a 12-week (90 min/session) integrated program for children with ADHD (training group). The participants' fitness levels and motor skills were assessed using standardized tests. Significant improvements in exercise capacity, cardiovascular fitness, and flexibility were observed in children with ADHD[33]. An RCT assessing the effects of a 12-week classroom-based intervention program for preschool children with ADHD (5 times/wk) randomly assigned children with ADHD to either a physical activity or sedentary classroom-based intervention, with 31 min of aerobic exercise per day during the school day. The physical activity intervention was more effective than the sedentary classroom intervention in reducing inattention and depressed mood in the home environment[34]. In a 6-week program of a comprehensive aerobic exercise training intervention (3 times/wk for 90 min each time; 60% of maximum heart rate), 15 boys with ADHD (the exercise group) were given an intervention consisting of specific exercises, such as a 200-m shuttle run, zigzag running, ball throwing, rope skipping, two 10-min sessions for different tasks, and a feedback phase. The exercise group showed significantly greater positive changes in DePaul ADHD rating scores (total and inattention scores), cooperativeness, and executive function than the control group at the post test period[35]. In an RCT, a medium- to high-intensity integrated movement intervention (40 min twice/wk) was specifically designed by the teacher for each classroom performance[36]. A general increase in participation of classroom learning activities and a reduction in ADHD symptoms were observed in children with ADHD after 12 weeks of the intervention.
In summary, long-term regular comprehensive exercise interventions significantly improve executive function and attention among children with ADHD. Comprehensive exercise intervention programs should be based on moderate-intensity aerobic exercise interventions, with a single session lasting no less than 30 min, and with an intervention period of ≥6 weeks (≥2 sessions/wk).
Effects of closed-skill ball sports on executive function and attention in children with ADHD
Acute closed-skill ball sports
Using basketball dribbling as a complex motor activity, a comprehensive study was conducted assessing the effects of a single 30-min exercise session at different intensities on children's executive function[37]. Moderate-intensity exercise in that study had positive effects on executive function. This finding is in line with the results of this group’s previous study that suggested that "moderate-intensity basketball improves children's executive function, but the effect is dependent on the duration of the exercise" [38]. In a summer treatment program using a closed-skill–based ball game program, 98 children with ADHD were randomly assigned to a treatment group (n=52) or a control group (n=46). The treatment group was assessed using the Bruininks-Oseretsky Test of Motor Proficiency (BOTMP) after 1 hour of skills practice and 2 hours of ball game team sports (football, baseball/softball, or basketball) per day. Children with ADHD showed improvements in football performance, BOTMP scores, catching accuracy, and handball spotting during basketball dribbling[39].
In summary, acute closed-skill ball sports improve executive function and attention in children with ADHD. In particular, those sports performed at a moderate intensity have a better effect than at a high intensity. Specific sports training (e.g., in ball sports), as opposed to simple running or cycling exercises, not only offers the opportunity to combine social behavior and motor skills to improve physical health, but also serves to promote the integration of children and adolescents with ADHD into school physical education and sports club routines in non-therapeutic settings[27].
Long-term closed-skill ball sports
In an RCT examining the effects of using a 12-week ball-based combined exercise program (60 min, 3 times per week) to improve physical fitness and neurotransmitter levels in children with ADHD, 12 children (grades 1-4) with ADHD were divided into control and intervention groups using a block randomization method. For combined exercise, the intervention group showed significant improvements in cardiorespiratory endurance, muscle strength and endurance, and flexibility. In addition, a significant increase in adrenaline levels was associated with a positive effect on overall fitness levels and neurotransmission in children with ADHD[40]. Children with ADHD also showed significant improvements in variables assessing working memory and motor performance in an RCT assessing ball sports interventions, suggesting that long-term ball sports interventions have a positive impact on executive function in children with ADHD[41]. In a football intervention, both immediate structure and detailed memory were significantly higher in the experimental group than in the waitlist control group; a 6-week football practice intervention improved executive function, particularly inhibitory control and cognitive flexibility, in boys with ADHD (aged 6-8 y) but had no significant effect on delayed working memory[42].
In a crossover trial assessing the effects of 12 weeks of table tennis training, children with ADHD showed improvements in motor behavior[43]. The effects achieved in the first phase of the intervention persisted in the second cycle, and the ball-slapping intervention promoted motor skills, social behavior, and executive function in children with ADHD. The effectiveness of a family-based rugby program in improving parent-child relationships for children with ADHD and their parents was investigated in a study by Siu et al[44]. A 6-week holistic sports intervention with 17 families showed that such a rugby program not only provides a quality space for family time but also enriches parent-child relationships in families with children with ADHD. Having a supportive and safe family play environment encouraged families to learn to better adapt to challenges[44]. A study by Kadri et al. assessed the effects of a 1.5-year Taekwondo exercise intervention (50 min twice/wk) in children with ADHD[45]. The authors used the Stroop task to assess inhibitory control of attention and the Ruff test to assess sustained attention and selective visual attention. Their results showed that test scores after the intervention for the Stroop color block tests and interference tests were significantly different between groups and that participants who received the Taekwondo program had better selective attention than children in the control group[45].
Effects of Somatic Play on Executive Function and Attention in Children with ADHD
Acute somatic play
Exergames, a combination of exercise and games, are human-computer interactive video games that use video motion capture and response tracking technology to instantly reflect body movements into the game system and simulate whole body movement. Exergames are an emerging tool in the field of motor intervention for children, as these interventions can distinguish between the specific and combined effects of cognitive and motor factors after motor interventions on executive function[46]. Existing research has shown that children with ADHD often find traditional (cognitive) training programs uninteresting and exhausting due to motivational problems and lower levels of positive reinforcement[47]. Motor games combine physical and cognitive training in a playful way, ensuring that features such as motivation, variety, and adaptability can be used as interventions that promote health-related outcomes and executive function in ADHD. Exergames are increasingly being incorporated into motor interventions for children with ADHD[48-49]. Considering that children with ADHD often drop out of traditional sports and spend approximately twice as much time (approximately 6 hours per day) sedentary in front of a screen, home-based video game interventions are particularly attractive for offsetting their potential for cognitive and motor deficits[50-51]. In an RCT conducted by Benzing and colleagues, 46 children with ADHD participated in an acute 15-min moderate-intensity exergame called Shape Up[52]. After playing Shape Up, the children were assessed with a modified version of the Flanker test and Color Span Backward Task. Children with ADHD who participated in the somatic experience performed significantly faster than controls on inhibition and switching, but there were no significant differences in accuracy or visual working memory performance on either task. Their results indicate the potential of acute somatic physical activity to improve specific aspects of executive function (inhibitory control and switching reaction times) in children with ADHD[52]. However, a meta-analysis found that inhibitory control did not improve significantly after somatic play training in children, which may be related to a different pathway of motor improvement for executive functions in children with ADHD vs. children without ADHD, or to less conflicting tasks in the content of somatic play[53].
Because the findings are inconsistent, the effects of acute somatic play interventions to improve executive function and attention in children with ADHD are inconclusive and will require further studies.
Long-term somatic play
Using a sensory-motor training program to stimulate the vestibular system, 12 children with ADHD completed a total of 20 sessions of motor training and cognitive training in a 4-month crossover design study. Sensory-motor training was associated with significant improvements in sensory integration and physical coordination and with significant reductions in behavior and emotional problems[54]. In another study, 47 children with ADHD used a visual and auditory stimulation play-motor program called Neurosync for 12 weeks (60 min, 2-3 times/wk)[55]. That study showed significant improvements in executive function as evidenced by significant increases in Stroop color, word, and color-word scores, indicating that sensory-motor training can positively influence cognitive development. In an RCT with an 8-week exercise game intervention (30 min, 3 times/wk), the exercise group of children with ADHD had significantly better specific executive functions (response time to inhibition and switching), inhibitory control, and cognitive flexibility than the control group, as well as improvements in general psychopathology and motor skills[56]. In a study focusing on a rehabilitative physical game intervention, an immersive virtual reality sports game was used as a rehabilitative intervention for children with ADHD[57]. After using an HTC VIVE virtual reality game console for 3 months, the children showed improvements in attention, hyperactivity/impulsivity, and confrontation.
In summary, the results indicate that long-term physical play has a positive impact on improving executive function and attention in children with ADHD.