De or het crosstraining?

The correct Dutch article is:

de crosstraining

Rule Words ending in -ing: almost always de. See the rule

How to use crosstraining

the crosstrainingde crosstraining
this crosstrainingdeze crosstraining
that crosstrainingdie crosstraining
our crosstrainingonze crosstraining
your crosstrainingjouw crosstraining
every crosstrainingelke crosstraining
which crosstraining?welke crosstraining?
a big crosstraining / the big crosstrainingeen grote crosstraining, de grote crosstraining