They're difficult as hell, but you feel like "gotta do 'em"
Overhand wide grip pull-ups - Very hard, always have been
In & Out Ab Crunches
Burpees
Uphill treadmill (6mph minimum) - IMO, the most efficient way to burn calories
Overhand wide grip pull-ups - Very hard, always have been
In & Out Ab Crunches
Burpees
Uphill treadmill (6mph minimum) - IMO, the most efficient way to burn calories