The debate over whether HIT (High Intensity Training) or volume training is better is one of the fiercest in bodybuilding. It has been raging for decades and is unlikely ever to be resolved. Although I am a believer in HIT, this article will not argue that HIT is better than other training method nor is it an exhaustive look at all aspects of HIT. Rather, it will serve as an introduction for those interested in HIT but are not sure where to start.
HIT is about finding ways to make your training harder but briefer. The theory is that the key factor in stimulating muscle growth is how hard you train (ie intensity) and not how often you train or for how long you train in each workout. But intense training is only one half of the equation. Rest is the other half. There is an old HIT adage that you can train hard or you can train long but you cannot do both. In other words, if you really train hard, you will not be physically able to train long. Therefore, HIT is about extremely hard, brief training and then getting out of the gym to rest.
There are many aspects to HIT theory but the following three HIT concepts should keep you on track.
Always train to failure
Never train two days in a row
Shorten your workouts and train less often as you get stronger
1: Always train to failure: There are all sorts of theories about how to measure intensity but the main HIT concept is that of failure. Failure is the point in a set at which you cannot perform another repetition despite your greatest effort. This is brutally difficult. Sets can be taken short of failure, to failure and even beyond failure (through advanced techniques). In HIT, all sets should be taken at least to the point of failure. Training must be progressive and every effort should be made to increase the weight lifted or number of repetitions performed from one workout to the next.
Training to failure puts a huge amount of stress on your muscles and your system as a whole, which is why training must be brief. As little as one set per exercise, taken to failure, is often enough to stimulate muscle growth. This means that HIT workouts are, by definition, short.
2: Never train two days in a row: HIT training not only necessitates short workouts but also plenty of rest between workouts. This is not only because your muscles grow when you rest (and not when you train) but because intense training puts great demands on your system as a whole. So even though you may only train one or two muscle groups in a workout, your whole body requires rest, not just those muscles that you trained. Therefore, HIT trainees should NEVER train two days in a row and should always have a MINIMUM of one day’s rest between workouts.
Shorten your workouts and train less often as you get stronger: Getting stronger means lifting heavier weights and that means putting increased stress on your system and your recovery abilities. Although training will improve your recovery ability, it will not improve as quickly as your strength, hence the need for fewer and shorter workouts as you get stronger. When you stop getting stronger, it is time to decrease training volume and/or frequency.
Putting it altogether
Those are the key concepts, but what does an HIT workout actually look like? Well there is no one answer and ideas have changed over the years as HIT trainees have experimented with different workouts. HIT workouts, like all workouts, can be split into whole body workouts and split routines.
3: Whole body workouts: This is the original HIT protocol, as pioneered by Nautilus inventor Arthur Jones in the late 60s and early 70s and advanced by Ellington Darden throughout the 80s and early 90s. The theory behind whole body workouts is to take advantage of what is called the “indirect growth affect”. When your body recovers from exercise, the chemical processes that stimulate growth take place throughout your whole body, not just in the muscle exercised. This is one reason why an exercise like squats can produce upper body muscle gains, hence the term “indirect growth”. If the body recovers as a whole, then it makes sense to train it as a whole. If you have trained all your muscles, all of them will be ready to benefit from your body’s overall recovery process by growing.
Early HIT workouts comprised whole body workouts of up to 20 sets and were performed three times a week – often on a Monday, Wednesday, Friday basis. All sets were taken to failure and exercises were often done in superset or tri-set fashion (ie no rest between sets) with only occasional breaks of one or two minutes.
Such workouts can quickly lead to overtraining and burnout (believe me, I’ve tried them) and even if you make progress for a while, the fact that as you get stronger you have to train less soon kicks in. At this point workouts need to be reduced to 10-12 sets or fewer and/or training frequency cut to twice a week.
When looking for ways to add more rest days, there is no need to think in terms of workouts per week. You can decide to take two days off between workouts, three days off between workouts or as many as you need to recover. Eventually, however, as you get stronger, even this volume may need to be reduced and this is where split routines enter into it.
Split routines: The main difference between split routines in HIT and regular or volume training is that HIT trainees split their routines in order to shorten their workouts and to train each muscle group less frequently. Volume trainers split their routines so that they can devote more time to each muscle group.
While the split routine does not take advantage of the “indirect growth” effect, it has the great advantage of enabling you to shorten workouts and maximise rest to an incredible degree.
Most HIT trainees start by splitting their workout into two parts and later into three and even four parts, which results in extremely short workouts – sometimes as short as 10 or 15 minutes. Even when following a split routine, you should not ever train two days in a row and the principle of adding additional rest days as you get stronger still stands. This can result in the type of routines that the late Mike Mentzer advocated, namely four-way splits with several days rest in between that has you training a muscle group only once every two weeks or so.
Repetition speed is a surprisingly controversial issue in HIT circles. The most commonly recommended repetition speed is two seconds to lift the weight and four seconds to lower it. This was the basic Nautilus recommendation in the 70s, although they also advocated slower repetitions (as slow as 30 seconds up, 30 seconds down) as an intensifying technique. All sorts of variations have since been tried and recommended and the no consensus has emerged. There does, however, seem to be general agreement that slow, controlled repetitions are the best and that you should lower weights more slowly than you lift them.
One of the things that really does separate many HIT purists from the wider bodybuilding population is that many of them do no advocate the standard high-protein bodybuilding diet and see diet as a relatively small factor in bodybuilding success. Arthur Jones, in response to persistent claims such as bodybuilding is 90% nutrition, is reported to have said words to the following effect: “Why 90%? Why not 100%? Just try not eating for a week and see what happens to your muscles.”
He and his followers did not believe in protein powders and told people not to waste their money on supplements. Ellington Darden, in particular, railed against high protein diets and supplements and while he still does not believe in high protein diets, he now acknowledges that some supplements do indeed work and is a creatine fan.
Most HIT trainees today, however, follow more conventional high-protein bodybuilding diets (correctly so, in my opinion) and advances in supplement technology over the past decade make it almost impossible to deny that some supplements work.
That, in summary, is HIT theory. If you choose to give it a try, remember that training to failure requires considerable drive and commitment and you will need to be honest with yourself at all times. Too many people do not really push their sets to failure (because it is so hard and so little fun) and then complain that HIT did not work for them. Do not cheat yourself. Give it your best shot.