fcfmuaythai,
I've competed in mma and grappling comps, tren does affect cardio in the short term, but I didn't have those problems when cycling with test.
I used fairly low doses, 37.5/mg/d for tren and 250 to 500 mg/w test enanth.
Started 10-12 weeks before fight for the test, 8-9 weeks for...