The 28-Day HIIT Challenge – Day 27

Rest for one minute after each round. Squat Sprint Jump Lunge Tiger Push-Up Seal Jump Burpee X-Jack

The 28-Day HIIT Challenge – Day 23

Sprint Squat Cross-Country Seal Mountain Climber X-Jack Push-Up Jack Jump Lunge Grasshopper Tiger Push-Up Burpee

The 28-Day HIIT Challenge – Day 19

Sprint Cross-Country Seal Power Knee Mountain Climber X-Jack The Mummy Reach Burpee Squat High Knee Jump Lunge

The 28-Day HIIT Challenge – Day 18

Yelling, “I’m a star!” as loudly as possible is optional during this routine, but highly recommended! That brief moment of levity may make you forget how much your legs and legs are burning during this blockbuster workout. X-Jack Jump Lunge Star Cross Push

The 28-Day HIIT Challenge – Day 17

Perform each set three times before moving to the next. Rest for 30 seconds between sets. Sprint High Knees Jumping Jack The Mummy Squat Reverse Lunge Lateral Lunge Squat Hold Plank Cross Jack Push Up Tricep Dip Pike Side Bend Russian Twist

The 28-Day HIIT Challenge – Day 16

Push-Up Squat Jumping Jack Plank Hold Cross Push Jump Lunge Tricep Dip Burpee 1-2 Push Squat Pedal Crab Touch Alternating Leg lift Burpee

The 28-Day HIIT Challenge – Day 15

For all levels, repeat the set four times. Rest for one minute after each set. Sprint Plank Jumping Jack Plank Rotation Squat Burpee Push-Up Seal Jack Plank Punch Squat Jump Alternating Leg Lift Burpee 1-2 Push Star In-and-Out Abs Squat Pedal

The 28-Day HIIT Challenge – Day 13

Rest for one minute after each round. Sprint Mountain Climber Cross Jack Crab Touch Side Suicides Tiger Push Up Skater Jump Russian Twist