Circuit Style Workout 

The quickest way to a six-pack isn’t lying on your back doing situps, it’s doing this workout. The Gut Punch hammers your entire lower body—your strongest muscles—and also your entire core. Use strict form and work hard, and your core will be so sore that you may not want to laugh for a week.

Directions: 

Grab two 16-kilogram kettlebells or 35-pound dumbbells, and do 50 reps of the stepup (25 on each leg). Then do 50 reps of feet-to-hands. (If that exercise is too advanced, do knees-to-elbows instead.) Repeat, this time doing 40 reps of each. Now repeat three more times, doing 30, 20, and 10 reps, respectively.

1. Dumbbell/Kettlebell Stepup

2. Feet-to-Hands (or Knees-to-Elbows)

Reps: 50, 40, 30, 20, 10 of Each

Time: 15 to 25 Minutes