Well, you could tie a cowbell around the kid's neck, and outfit him in a t-shirt-onsie that says "more cowbell! cuz my moma can kick your moma's butt!"... that way you would have both a cheering section, and a locator device for after the race... jk ...but creative multi-tasking you gotta say lol.

The teenager idea at the race is not a bad one. Or whatever other fellow team mates might use for child care. Or whatever other babysitting options you have, grandma, nice neighbor, something.

Lack of child care sadly kept me away from the gym and other activities for a number of years. Good Luck!