Has your workout "HIIT" a wall? High-intensity interval training, also known as HIIT, is a toning technique that mixes quick bursts of energy with short intervals of rest. This popular fitness method crushes calories, increases metabolic health, and improves heart health. It can also be done virtually anywhere, at any time.

Begin a HIIT routine with bodyweight exercises, then graduate to more challenging circuits by incorporating free weights.

Check out this sample beginner's workout:
Directions: Complete the following circuit four times, resting for one minute after each full circuit.

25 push-ups
Keep your core tight and maintain a straight line from your head to your heels. 

30 jumping jacks
Land softly on the balls of your feet with each repetition. 

25 air squats
Hinge back at the hips until the thighs are parallel to the floor and push through your heels to return to the starting position.

Now, make the most of your HIIT routine by avoiding these common mistakes:

Don't waste your time. A HIIT circuit requires less time than other routines and yields greater results due to its intense nature. If you are truly pushing yourself during the highs of your HIIT circuit, your muscles will fatigue in 30 minutes or less. That means there should be little rest between repetitions, if at all. Once you start slowing down to tap off a quick text message or toy around with your music, precious time is lost.

Max out. The goal of HIIT is to keep your heart rate elevated and to safely push yourself to the limit. Once you feel comfortable and confident with the proper form necessary for each exercise, increase your repetitions, pace or intensity.

Know when to HIIT it. Taking time to rest and recover is one of the most important factors of a HIIT routine. In order to produce a powerful push for each exercise and to prevent injuries, muscles need to be well-rested. Similarly, switching up your training routine on non-HIIT days is necessary for focusing on other fitness factors such as flexibility, stability and heavier weight training. For best results, try incorporating two or three HIIT routines into your weekly schedule.

Practice proper training techniques so you aren't a one-HIIT wonder.