You've attacked day 1 of the workout program and if we had to guess, your chest, shoulders, and triceps are really starting to feel it. So now it's time to focus on building your strength and power from the ground up—with this muscle-burning leg circuit.

You might be asking yourself how strengthening your legs will help get you to a six-pack, but it's important to keep in mind that muscles are connected, so building strength in your lower half can only help you boost growth in your upper body.

The workout: Day 2

1A. Goblet Squat

Sets: 4
Reps: 10-12
Rest: 30 sec.

1B. Walking Lunge

Sets: 4
Reps: 10-12
Rest: 30 sec.

1C. Lateral Lunge

Sets: 4
Reps: 10-12 (each leg)
Rest: 30 sec.

2A. Romanian Deadlift

Sets: 3
Reps: 10-12 (each side)
Rest: 30 sec.

2B. Single-Leg Glute Bridge

Sets: 3
Reps: 10-12 (each leg)
Rest: 30 sec.