Bodybuilding undoubtedly got a lot from Mike Mentzer, an incredibly influential bodybuilder of the 1970s and advocate of the Heavy Duty method (HIT).
Nearly 20 years after his death, Mike Mentzer’s Heavy Duty high intensity training philosophy still sparks a lot of debate among bodybuilders.
In his books, Mike claimed that his Heavy Duty training was, in essence, a scientific approach to training. In fact, in the book “The Science of Bodybuilding” in Chapter 3, he describes his key training principles.
However, while his approach certainly seems logical at first glance, it is difficult for most beginners or intermediates to assess whether scientific research on hypertrophy training supports this claim.
This is simply because most people don’t have easy access to the (sometimes obscure) how to examine this topic.
Therefore, we will explain in this summary how to test Mike’s theories and his key principles in relation to what we know about Heavy Duty .
Concepts about Heavy Duty
After retiring from bodybuilding, he took this type of “HIT” high intensity training even further, advocating a technique with very low volume, few reps, and heavy training with several days of rest between each workout … the popular Heavy Duty …
Each brutal session consisted of a small number of exercises performed for 6 to 9 repetitions until muscle failure and often beyond.
Forced repetitions, super slow negatives and rest-pauses were common and were even beginning to become popular and, this Heavy Duty started out as controversial and highly debated.
In this sense, even lower volume Heavy Duty routines have much longer time under tension with more intensity than average training and this can translate into a better investment in the gym.
The Heavy Duty is very intense
Mentzer believed in training thoroughly at incredibly low volume and then recovering, sometimes taking up to 10 days before re-training a muscle.
Its definition of intensity does not refer to the percentage of a maximum repetition (1RM), but to the difficulty of an exercise and how close you are working to complete muscle failure.
His work focused on gradually increasing training intensity, rather than training to failure immediately.
Once an athlete is able to create large amounts of tension in their muscles, the key to developing more size is not to train longer and with more volume, but to use increasingly intense methods and make training difficult.
Mentzer used rest-pause sets, descents, and pre-fatigue methods to perform exercises that would complete muscle failure.
With Heavy Duty I believed that taking advantage of this level of intensity was the key to unlocking muscles and gaining greater gains in strength and size.
Additionally, he was an avid advocate of integrating tempos into his training to focus exclusively on developing the strongest muscle contraction he can, rather than harnessing momentum to move weight.
And while you may not agree with his, you can still benefit from his wisdom:
- Control each rep to maximize intramuscular tension.
- Push the intensity in each set to the point of technical failure and occasionally to muscle failure.
You will most likely benefit from doing less (but doing better) exercises.
The Heavy Duty needs recovery
Mentzer believed that most bodybuilders were overtrained and poorly recovered, which limited muscle growth.
The point is that when low overall training volume and relatively infrequent workouts are combined, any exercise carried beyond the “minimum effective dose” is wasteful and counterproductive.
This tip is more relevant today, where we see bodybuilders who train harder and harder than before, but are also more stressed, sleep less, and recover less than ever.
An often forgotten truth? … you can only grow with training you can recover from …
Mentzer with his Heavy Duty focused on one or two total work sets per exercise with two workouts per week separated by at least 48 hours. A classic rotation of three exercises could be:
- First workout: chest, shoulders, triceps.
- Second workout: back, biceps.
- Third workout: legs, abs.
Do one or two warm-up sets, then an effective set to reach muscle failure for each exercise:
Taken to extreme levels, Mentzer was said to only train muscles every 10-12 days, so infrequently that it is a training plan difficult to imagine.
What happens is almost all bodybuilders would benefit from a greater focus on recovery, remembering that recovery requirements increase as strength and intensity of workouts is increased.
Stress é s is necessary for growth, but growth only occurs when you fully recover.
Pay attention to Mentzer’s words: “Abnormal muscle strength and growth require an abnormal focus on recovery.”
Train hard, but make a full recovery
The Heavy Duty is slow
Mentzer used slow, controlled reps to maximize tension and intramuscular control – he said if you can’t pause a lift and contract it, you used momentum to get there.
Here’s where it gets interesting: Mentzer is thought to be a “low volume” guy, and by all accounts this is correct when you consider that training volume is classically defined as “sets x reps.”
What happens is that the duration of each repetition and, by extension, the duration of each series is often not taken into account.
As an example, a cadence of 5-1-5-0 (5 seconds to lower, 1 second to the bottom, 5 seconds to lift, 0 seconds to rest at the top) would take 11 seconds per rep.
This means that a set of 5 reps would take almost a full minute and this ALSO means that a set of 5 reps, which is classically considered a “strength rep range”, clearly has a duration of time under tension that is related to a stimulus for muscle development.
According to research (from Hulmi et al), anabolic effectors of AMPK and mTOR are higher with hypertrophy rep training protocols than with strength protocols.
Compared to the average bodybuilder, who focuses primarily on moving weight without paying attention to tempo, the volume of Mentzer’s workouts could be comparable to that of a more typical program.
Control your mind-muscle connection
The Heavy Duty is effective
To trigger muscle growth, you must master all three types of muscle contraction: concentric, eccentric, and isometric.
Mentzer’s philosophy regarding training tempos for these phases of the lift caused him to increase the intensity and hence the label of “high intensity training”… this is what he believed in doing for each one –
For the isometric
- In this contraction there is no shortening or elongation despite a maximum contraction.
- You’re activating your muscles as hard as possible, but not moving, allowing you to maximize muscle fiber recruitment and improve your mind-muscle connection without excessive joint stress.
- Similarly, Mentzer used single and multiple joint exercises and various muscle positions for isometric holds.
Upper body lifts generally lasted 8 to 12 seconds, while lower body lifts ranged from 12 to 30 seconds or more, holding a weight in an isometric contraction, often concluding with a slow eccentric movement with the help of a partner.
Obviously, this must be done safely: Mentzer took precautions by leveraging isometrics in conjunction with eccentric tempos, meaning he often scheduled single-joint exercises and machine work to limit the risk of injury.
Working with a partner serves to help lift a supra-maximal load into place in the middle of a contraction, before holding the weight for a while.
Due to the risk of injury, this technique is not recommended, but you can still get similar benefits by lifting a near maximum weight, holding one position for 8-12 seconds in an upper body lift (or 12-30 seconds in a lower body raise) before lowering it as slowly as possible.
For the concentric
- It is the classic lifting phase in which the muscle shortens and, during this phase, you can use a variety of tempos, slow and fast.
For the eccentric
- In this “lowering” phase of the lift, where the muscle is lengthening, it is advisable to use slow or long movements and overload movements, using the greatest possible range of movement so that your muscles are stretched by complete.
- Use slow speed and tempo to create as much tension as possible, maintaining a heavy load to stimulate maximum contraction.
Mentzer used to use tempos like 5-1-5-0 in the Heavy Duty , which uses a five second eccentric phase, a one second pause at the bottom to dispel the stretch reflex, a concentric phase of five seconds and no pause at the top, which means it was going straight to the next rep.
Heavy Duty takes time
Mentzer was right when he said: “A training method that is currently attributed to a champion is not one that he has always been training.”
The biggest mistake young people make?
- Adopt the advanced training methodologies of elite bodybuilders before building a sufficient base of strength and quality of movement.
- In essence, there is no need to train like a bodybuilder before competing, especially if you don’t have a foundation of strength, quality of movement, and well-rounded lifestyle to maximize the demands of such workouts.
The “combat” in the Heavy Duty
Mentzer often preached the idea of the siege mindset – a mindset fully committed to fighting in the gym.
He believed that humans evolved through fighting and combat, and the gym became the modern setting for people to fight and eventually grow up.
But the siege mentality cannot be misinterpreted as a lack of patience, as according to experts, physical changes are cyclical rather than linear.
Changes in body fat index and hypertrophy occur suddenly after durations of focused work, and not in a linear fashion.
This is true, because you must have the intensity to approach the gym with concentration and determination and, thus after weeks and months using Heavy Duty or other techniques you can break your state if you are stuck. In this way, transformations in your physique can occur seemingly overnight.
And, in today’s instant gratification society, this is something we can all apply both in and out of the gym.
Take advantage of patience and total determination in the gym, embrace the challenge but remember: “Progress is rarely linear, it is cyclical” and only those who stay the course will succeed.
Many say that Mentzer took his technique too far, but his ideas are still stimulating for many athletes, including Roberto Castellano, our professional coach who shows us in a video how to train the Heavy Duty adapted for biceps.
A practical application
While it is not necessary to agree with every part of the Mentzer philosophy, there is something you can learn in all cases with Heavy Duty .
- From time to time, dial in the intensity and drastically reduce the volume.
- Vary your muscle contractions to maximize growth.
- Be brave, even when in doubt, above all else adopt the siege mentality.
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