Pfft.. 20 hours???
Bro's at our gym brag how they are there 3 hrs a day, 7 days a week!! 
I told one guy "ya, but you dont know how to train, and flap your gums for 2.5 hours of it".
He's a buddy, so he sort of laughed I guess (knowing its the truth)...
This.
If you time the amount of work done but those guys, it's minimal.
That's why if you design a workout that actually incorporates an hour of actual exercise, they gas.
I printed out one of SC's old workouts that had you do a 45 sec to a minute straight of an exercise, then 15 sec rest, then repeat with a new exercise.....for 45 min to an hour.
It was f'n brutal, but got me in good shape fast.