Despite growing in popularity over the last ten years or so, HIIT remains an area of health and fitness still shrouded in mystery. If you are attempting to determine how to build muscle effectively this is one area you definitely need to look into.

Many people who perform this type of exercise are going for weight loss, however there is also a major use here for those looking to improve size and strength.

If most men were honest, they'd happily admit that they don't do enough cardiovascular exercise. It's often seen as the boring alternative to resistance training and they don't have the same level of drive for it.

This is largely because there is a false mentality in most gyms that cardio is for girls. Most guys deem it too boring and not engaging enough.

Believe it or not, if your main target in the gym is to build more lean muscle then cardiovascular exercise will indeed play a huge role in your accomplishments. There are several effective forms of cardio which improve fitness and hypertrophy, most notably high intensity interval training.

That's right. Even though it's cardio, you will still be able to get bigger. This is largely because of the intensity of the work. Although you might be using a treadmill or an exercise bike, your workout isn't going to be a dull, slow paced, aerobic affair.

High intensity interval training is based around constantly switching between moderate and high intensities, causing your body to tap into both it's aerobic and anaerobic energy systems. There are striking similarities between an interval training session and a resistance workout.

While performing a resistance exercise your body is tapping into it's anaerobic exercise. This is the same system you'll use while performing any high intensity cardio workouts, too.

Things get even better when you look at how your body burns calories during this type of training. During a normal session your body stops burning calories when you stop exercising. However, if you have performed an interval session your body will continue to burn calories at an increased rate for 16 hours afterwards! This is also known as 'the afterburn effect'.

Over the years it has been proven that HIIT helps you to lose more body fat than regular cardio workouts. If you are trying to figure out how to build muscle you should also be including this type of training in your workouts, as it has been proven that short bursts of high intensity activity will tap into your body's anaerobic energy system and make it easier for you to experience muscular hypertrophy.