De or het loopkleding?

The correct Dutch article is:

de loopkleding

Rule Words ending in -ing: almost always de. See the rule
Meaning (Dutch) gespecialiseerde sportkleding, ontworpen om comfortabel en functioneel te hardlopen.

How to use loopkleding

the loopkledingde loopkleding
this loopkledingdeze loopkleding
that loopkledingdie loopkleding
our loopkledingonze loopkleding
your loopkledingjouw loopkleding
every loopkledingelke loopkleding
which loopkleding?welke loopkleding?
a big loopkleding / the big loopkledingeen grote loopkleding, de grote loopkleding

Meaning, plural, diminutive, pronunciation and translations: WikiWoordenboek (Dutch Wiktionary) (CC BY-SA 4.0). Example sentences: Tatoeba (CC BY 2.0 FR).