Exercise as it relates to Disease/The effects of physical activity on children with ADHD

This is a critical appraisal of the journal article "Physical Activity, Affect, and Cognition in Children With Symptoms of ADHD" by Gawrilow et al (2013).

What is the background to this research?
Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder, most commonly discovered in young children. ADHD impairs the ability to concentrate and often results in hyperactive behaviour. It is one of the most common childhood psychiatric diseases occurring in 5-10% of all children, most commonly found in boys. The most common course of treatment for sufferers of ADHD is stimulant and non-stimulant medications. Up until the time this article was published, there was little research conducted into the effects of physical activity on the symptoms of ADHD. The purpose of the study was to examine the role of physical activity on the executive functioning of children with ADHD.

Where is the research from?
This study was conducted in a psychiatric clinic in Luneburg, Germany.

What kind of research was this?
This study was a two group, randomised, controlled study. It measured both quantitative and qualitative data, measuring the number of correct answers on a computer test as well as the perceived commitment and task difficulty.

What did the research involve?
All participants were initially screened to ensure they met ICD-10 ADHD core symptoms to establish a controlled and reliable study. All participants then completed an attention task via a computer lasting for six minutes to establish a baseline for adaptive testing. Prior to the test, participants completed 20 practice tests to get familiar with the format. Following this, participants were then randomly split into two groups. The first group were asked to jump continuously on a trampoline for five minutes, ensuring intensity levels remained consistent. The second group were asked to sit and color pictures for five minutes.

Following this, participants were asked to complete a twenty one minute stimulus classification task. This activity required participants to classify animals and modes of transport into their respective categories as well as cease classification in response to a stop signal. The number of successful stops and response times were then recorded as dependent variables. Lastly, the participants perceived commitment and task difficulty were measured using a scaled approach.

One of the major limitations of the study is that only male participants were included. Although males have a much higher prevalence of ADHD, the disease is not exclusive to males and therefore it would have been beneficial to include female participants. Another limitation of the study is the geographic sample size. Participants were only recruited from one facility in Germany and therefore, this sample group does not reflect the wider community. A third limitation of the study is the length of time spent engaging in physical activity. To expand on the results, the study should have included a larger amount of groups undertaking different lengths and intensities of physical activity.

What were the basic results?
The results of the study confirmed the initial hypothesis that physical activity improves executive functioning. The study demonstrated that even five minutes of moderate physical activity can significantly improve concentration for a child suffering from ADHD.

The participants who completed the physical activity showed a median successful response of 76.83 with a standard deviation of 21.68 in the classification activity. This is significantly higher than those who completed the sedentary activity with a median successful response of 65.54 and a standard deviation of 30.10. This trend carried over into the activity that required participants to cease classification when presented with a stop signal. Participants who completed the physical activity showed a median error of 32.78 with a standard deviation of 26.61. Participants who completed the sedentary activity showed a median error of 46.08 with a standard deviation of 35.28. Both groups however, reported similar perceived commitment and task difficulty measures.

The researchers of this study were confident in their conclusion that physical activity does improve the executive functioning of children with ADHD, however they also recognised that there were significant limitations to their research. For example, they recognised that in order to understand the full effects of physical activity on executive functioning, they would need to include a comparison group comprising of children without ADHD. They also questioned the validity of the study as many of the participants were taking stimulant medication at the time of testing which may have altered the results. Therefore, further studies are needed to investigate the effect of physical activity on children with ADHD who are not taking medication.

What conclusions can we take from this research?
Based on the appraised study, it is difficult to definitively make a judgement regarding the degree to which physical activity affects the executive functioning of children with ADHD. This is due to the fact that there are significant limitations to the study and as such, the limitations should be considered when reviewing the results. However, when reviewing the appraised study, combined with the results of a numerous other studies, it is evident that there is a clear correlation between physical activity and improved executive functioning in children with ADHD.

Some studies that align with the results of the appraised study are as follows:
 * "The Effect of Physical Activity on Children With ADHD: A Quantitative Review of the Literature" by Cornelius, Fedewa and Ahn (2017)
 * "Effects of physical activity on executive function and motor performance in children with ADHD" by Ziereis and Jansen (2015)
 * "Effects of Physical Activity on Academic Performance and Behavior in Children with ADHD" by Flohr et al. (2004)
 * "The effect of acute exercise on cognitive performance in children with and without ADHD" by Piepmeier et al. (2015)

Practical advice
This research has a significant potential to influence the treatment prescribed for children with ADHD. Although physical activity has not yet shown to be as effective as medications, it can be stated that physical activity should be prescribed by doctors as part of an overall treatment plan.