I would assume that increased focus and less impulsivity would be an asset in most athletics. If he loses his spark, he’s on too high of a dose or the wrong ADHD medication.
Here’s more on ADHD medication:
A Patient’s Primer on the Stimulant Medications Used to Treat ADHD
Penny
ADDitude Community Moderator, Author & Mentor on Parenting ADHD, Mom to teen w/ ADHD, LDs, and autism