People push through the grueling 30-60 minute workout in "Insanity." (Creative Commons)

The sound of heavy breathing, the banging against a hardwood floor and a man’s stringent voice yelling, “keep pushing through, come on, reach higher, grab your hands, push...push...PUSH,” was all I heard as I walked past a closed door in my sorority house, late one night.

Not long afterwards, four tired but content-looking girls emerged with disheveled hair,soaking in sweat. 

Curious, I asked them what they were doing. 

“Insanity,” they said. 

My face must have looked perplexed because I found out shortly afterwards that "Insanity," although insanely difficult, it not what it sounds like. 

The 60-day, six-day a week, exercise program uses interval training to help people lose weight and tone muscle.

Trainer Shaun T. leads individuals through a strenuous warm up, a stretching set and then alternates between three minutes of demanding exercises and 30-seconds of rest.The idea is to work as hard as you can, take a short rest and then do it all over again for the entire 30-to-60 minute video. 

Through a DVD series, the entire workout can be done at home, without any equipment, using only your body and a pair of sturdy tennis shoes.Depending on where you are in the program, the exercises are diverse, varying from jumping jacks and squats to uppercut punches and basketball ball jump and shoot drills. Overall, there is a lot of jumping and getting up and down off the floor. 

“I've always worked out, but this was way more effective because it targeted all of my muscles and literally kicked my ass every time,” Lizzie Pereira, a USC student who finished the entire 60-day program earlier this year, said. 

"Insanity" is not meant for the easily discouraged or unhealthy individuals that have never worked out before popping in Shaun T’s DVD. The exercises are designed to challenge you and push you to your max, which is more taxing but it is a way to cultivatefaster results. However, it takes a certain amount of drive to fully commit to that degree of intensity for two months. 

“Sometimes they got a little repetitive and there were definitely times where the thought of doing the videos sounded so grueling and exhausting,” Pereira said. “But after I finished a workout I always felt happy and proud that I had done it.” 

But does the program actually work? 

Well, it depends on what you want from it. The program is designed to help stimulate weight loss and tone muscle but will not help someone trying to build larger, bulkier muscle since there is no weight lifting. 

For Pereria, the program conditioned and sculpted her muscles.

“I definitely have noticed a change in my body and others have too," Pereria said. I'm way more toned, especially in my arms. They haven't looked this in-shape ever.”  

Starting and committing to the program with friends is one way to keep with it through all 60 days and combat the desire to skip workouts. 

Even after completing the two-month challenge, Pereria still does "Insanity" three times a week, switching off between DVD's, the gym and running.

"I absolutely loved the program and really can't express how well it works to get people in shape," she said. 

To read a doctor's review of the exercise program click here. 

FitGirl is a weekly health and fitness column that comes out every Thursday. If you have any questions you want to see answered feel free to email me.