The rationale of this clinical trial is to identify the intervention that best contributes to better cognition results of adults with ADHD's: physical activity, drug or a combination of the two? The study will enable to determine which factor will improve cognitive results. The findings of this trial will help determine the best treatment method that can be offer to adults with ADHD.
Randomized clinical trial in which individuals who have been diagnosed with ADHD and are regularly treated with Methylphenidate will be test for cognitive performance and will be randomly examined in the following four conditions:~While taking Methylphenidate and sitting at a desk~While taking Methylphenidate and walking on a treadmill workstation~Without taking Methylphenidate while sitting at a desk~Without taking Methylphenidate while walking on a treadmill workstation The investigators will compare the cognitive achievements outcomes and evaluate the efficiency of studying in each of these four conditions.