Strength training workouts fall into two broad categories; low volume with high intensity or high volume with moderate intensity. Both types of training can be effective when used properly, but high intensity training, also known as HIT, requires less frequent, and much shorter, workouts.
Typical high volume strength training requires that you perform multiple sets of multiple exercises per muscle group. Sets are not taken to failure, that is to say you will still be able to perform a couple more reps, although doing them will be very demanding. In contrast, HIT workouts are performed to muscular failure and only one or two sets are performed per exercise and per muscle group. Muscular failure means that you are unable to perform any more repetitions. This high level of intensity is often complemented with the use of workout intensifiers such as drop sets, isometric or static holds, forced reps and negative reps. These methods allow you to push your muscles beyond their normal point of failure.
How HIT Works
Proponents of HIT believe that it is not the volume of exercise that is important in strength training but rather the level of intensity reached. By exerting maximal effort, you will provide all the necessary stimulus needed for optimum muscle growth. Longer workouts, it is argued, simply inhibit recovery. M. Doug McGuff, M.D., co-author of "Body By Science," likens strength training to certain drug therapies and suggests that there is a dose/response relationship between exercise and intensity. He states that short but intense workouts are as effective as more traditional forms of training despite the lower volume. Longer workouts, says McGuff, are merely a waste of valuable time and effort.
In HIT, as relatively few exercises are performed, exercisers are encouraged to choose compound or multi joint exercises that stimulate the greatest amount of muscle in the shortest amount of time. Bench presses, leg presses, pullovers and dips are all popular HIT exercises.
In some types of HIT, machines are preferred so that you are able to focus on doing as many repetitions as possible without the worry of a free weight crashing down unexpectedly. HIT usually utilizes whole body workouts, although some bodybuilders favor split routines where different muscles are trained on different days. Mike Mentzer, who was Mr. America in 1976, used HIT and wrote numerous books about this type of training, which he called "Heavy Duty."
The Colorado HIT Experiment
In 1973, HIT advocate and scientist Arthur Jones trained bodybuilder Casey Viator for 28 days using HIT training protocols and his newly designed Nautilus strength training machines. After the 28 days of training, which totaled only fourteen workouts, Jones reported that Viator had added 45 pounds to his frame.
Some believe this study is misleading because much of the weight Viator gained was actually muscle mass he regained after an injury that occurred before the experiment. Nevertheless, Jones himself, by following the very same workout program, gained almost 14 pounds in the same time frame. More recently, Timothy Ferris, author of "The Four Hour Body," reportedly gained 34 pounds using HIT training.
HIT can be very effective, but it may not be suitable for all exercisers. The workouts are hard and painful and are not really meant for beginners. In addition, sustaining such a high level of intensity week after week can be very psychologically demanding. Some bodybuilders denounce HIT because more traditional training methods have produced more champions than HIT has. HIT is a good change from the norm if you usually train using a moderate intensity/high volume approach and it is especially useful if you find it hard to find the time to exercise.
- Body by Science: A Research Based Program to Get the Results You Want in 12 Minutes a Week; John R. Little and Doug Mcguff
- Heavy Duty; Mike Mentzer
- Four Hour Body; Timothy Ferris
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