There’s hitting the gym … and then there’s HIITing it.

And you’ve got the option to’t really compare the two.

Here are the most common HIIT mistakes Michaels sees.

Jillian Michaels

“They don’t warm up!”

Are they just so excited to get moving that they forget about this key part of any workout?

“[This is] simply not the case.”

jumping rope

Before you begin your HIIT workout, get your body moving, Michaels added.

This doesn’t have to be anything elaborate.

“[It] could be a brisk walk or light jog around the block.”

lazy workout

A little jump-roping is always a good warm-up; so is shadow boxing.

If all else fails?

“Walking the stairs in your apartment complex” will suffice, according to Michaels.

workout recovery

“HIIT training is meant to be ‘high intensity.’

That’s the whole point,” Michaels said.

You are supposed to feel uncomfortable, sweaty, with labored breathing; this isnotyoga or chair aerobics.

treadmill runner

According to Michaels, math is your friend.

This is an easy, tried-and-true formula, Michaels added.

“you’re free to get this number by simply subtracting your age from 220.

spin bike

So for example, a 35 year old’s MHR would be 220 minus 35.

That would be an MHR of 185 beats per minute.”

“For example: 45 seconds on, 15 seconds off,” she explained.

“People train for too long!”

“HIIT workouts are meant to be shorter in overall duration.”

“You have to remember that intensity has an inverse relationship with duration,” Michaels added.

“The harder you train, the shorter your workout should be.”

This is not, after all, a marathon.

But in fact, according to Michaels, the HIIT exercises should be really simple.

“Don’t overcomplicate your HIIT workouts,” she urged.

You might want to incorporate equipment, if you have it handy.

That being said, HIIT is designed to work just as well with absolutely no gym paraphernalia at all.

“If no equipment is available, use your body as your tool,” Michaels explained.