The use of "du"

[jewels]

I was wondering why "du" is used in the following sentences:

Le garcon fait du cheval.

La fille fait du velo.

du pain= (some) bread

I understand that in the bread case "du" is a partitive article and used to express quantities that cannot be counted. Cheval and velo seem to be countable so why is "du" used  ?

Thanks

Jewels

[Isabelle75Paris]

"du" or "de la" (if it's feminine) will be use after the verb "faire" to express the action of doing or making something.