PIIT28, a fun fusion of Pilates and HIIT exercises, needs nothing however your shoes and a yoga mat. And the best part? It's only 28 minutes and 40 seconds of your day. Don't be fooled, though — even though it's short, you'll definitely work up a sweat.

Through the 28-day program, people haven't just slimmed down, but more importantly, found strength and confidence through the workout.

"You feel invincible and powerful. Yes, people want to lose weight, but that can't be your main focus. Your focus should be to get stronger and to have fun while you're doing it," Ho says. "If you stick with those two things, you're more likely to stick with your routine. That's going to be the gold right there. Your body will really start changing."

The program itself prices but most monthly athletic facility memberships at $40, but you can try out some of the moves for free below.

  1. Mountain Climbers

How It's Done: Begin in a full plank. Exhale, and pull your right knee in toward your hands. Inhale, and extend the leg back to plank. Repeat alternating sides and rise as quick as you'll be able to.

Modification: Either bring your knees into your chest at a slower pace, or drop to a plank on your knees and bring them into your chest slowly, one at a time.

  1. Criss-Cross

How It's Done: Lie on your back with your legs in tabletop and your hands behind the nape of your neck, elbows wide. Exhale, then lift the right shoulder off the mat and bring it toward the left knee. Inhale, return to start, and alternate to the other side.

Modification: Keep your head, neck, and shoulders on the mat, and solely perform the exercise with the legs.

  1. Wide High Knees

How It's Done: Standing tall, feet wider than hip distance apart, jump from one foot while bringing your opposite knee up as high as possible. Next, jump with the other foot and repeat.

Modification: Omit the jump and easily bring one knee up as high as attainable whereas alternating legs.