A cyclist just got busted for Clen in the Tour d France last time. So for the endurance part she would need to listen to her body. For myself I run for 20 minutes while on clen no problems. HIIT on the other hand leaves my head spinning. My $.02 have her start with a low dose and slowly up it as she learns what it's doing to her body.

As for "sluggish" after cycle. Well while on I feel increased endurance and performance so comparing it to off, yeah I guess I'm not as peppy. But it's not lower than normal / pre cycle or anything. Just not as good as when on.