Lots of things we do are catabolic, but I would just say that long distance steady state running is definitely not conducive to building mass. I do know, however, that I am forced to do some running and I don't feel like it's cost me much mass.
Bodyweight- 231, currently cutting to under 220
Raw total- 1280
Geared total- 1480
Best gym lifts, single ply-
Only goal- ELITE as soon as humanly (and chemically) possible.