Mike Mentzer’s Heavy Duty training system was a revolution. For the year between the 1979 and 1980 Mr. Olympias, as high-intensity training (HIT) rode the crest of its foremost adherent, Mike Mentzer, it seemed on the verge of transforming bodybuilding. Mentzer had adopted the HIT philosophy of Arthur Jones and expanded it into his own radical system, which Mentzer named Heavy Duty. Reps got lower, weights got bigger, sets got much harder. Heavy Duty continues to impact weight-training over four decades later.

Mike Mentzer workout
Mike Mentzer, circa 1980

The Barbell examines Mike Mentzer’s high-intensity training system: Heavy Duty.


When 19-year-old Casey Viator won the 1971 Mr. America after training HIT-style under Arthur Jones’ tutelage it caused a sensation in the bodybuilding world. Viator’s victory eclipsed the fact that a second 19-year-old phenom, Mike Mentzer, was an impressive 10th in that same contest. The new Mr. America introduced the other teenager to Arthur Jones. Soon thereafter, Mike Mentzer began consulting with HIT’s creator and revamping his training. When Mentzer won the 1976 Mr. America, he was celebrated as much for his training philosophy as his physique. He wrote articles for the leading bodybuilding magazine, Muscle Builder/Power, focused on techniques for intensifying workouts.

For much more about the philosophies of Jones, Viator, Mentzer, Dorian Yates, and others, check out: The Amazing History of High-Intensity Training


Mike Mentzer advocated a heavier form of HIT. Whereas Arthur Jones prescribed one 20-rep set per exercise, Mentzer lowered the ideal rep-range to 6-8. Choose a weight so heavy that you reach absolute failure at 6-8 reps. Then keep going. Failure wasn’t enough for Mentzer’s Heavy Duty system. It went beyond. The techniques Heavy Duty prescribed foremost were forced reps, negative reps, rest-pause, and pre-exhaust, especially pre-exhaust supersets.

? Forced Reps A spotter helps just enough to keep the weight moving for additional reps.

? Negative Reps A spotter helps a lot on the positive halves of reps, and you then slowly lower the weight over approximately six seconds.

? Rest-Pause After reaching failure, rest for approximately 15 seconds and perform anther rep. Repeat for 2-3 reps. Mentzer had another way of doing a rest-pause set: 4-6 max single reps with a rest of 10-15 seconds between each rep and a 20% reduction of weight near the end in order to get that last rep or two.

? Pre-Exhaust Supersets Do a set of an isolation exercise before a set of a compound exercise for that same body part without resting. The muscles targeted with the isolation exercise work to their maximum and give out first during the compound exercise.

Mike Mentzer trained with at least one partner (frequently his younger brother, Ray, 1979 Mr. America winner) who spotted him and assisted when he reached failure. The partner removed just enough stress for two or three forced reps. He helped raise the weight so it could be lowered as slowly as possible on negative reps. Or he spotted while Mike Mentzer paused between reps and grinded out a few rest-pause reps. Heavy Duty, indeed.

Mike Mentzer workout
Mike Mentzer helps brother Ray go beyond failure on machine shoulder presses.

The other key component of HIT is the low workout volume. “The secret, if there is one, is high intensity. And when you actually train with high-intensity, you don’t need a lot of volume,” Arthur Jones said. In 1979, Mentzer prescribed only 3-6 working sets per body part (supersets count as two sets), with typically one or two lighter warmup sets per exercise. He also prescribed only three weekly workouts, though Heavy Duty did call for training body parts twice every 8-9 days (most modern bodybuilders work body parts only once weekly).

“If you’re skeptical [of Heavy Duty’s low volume], your subconscious child is telling you that more is better,” Mike Mentzer wrote. “In some cases, that’s true. More money is better than less. But you can’t take that principle and blindly apply it to exercise and expect to get anything out of it.”


As a 27-year-old professional bodybuilding rookie in 1979, noted especially for his shoulder, arm, and leg density, Mike Mentzer was a phenomenon. Capping off the year by winning the heavyweight division of the Mr. Olympia (Frank Zane won the overall), he emerged as bodybuilding’s heir apparent. Mentzer released two popular Heavy Duty booklets in 1980, and, through his articles, seminars, and mail-order business, his philosophy was as great a sensation as he was on stages.

Mike Mentzer Heavy Duty
Mentzer grinds out leg extensions.

It seemed every bodybuilder tried his lower-rep HIT, though most eventually returned to a more moderate system. Then came the 1980 Mr. Olympia. The greatest representative of the old guard, Arnold Schwarzenegger, won. The insurgent 28-year-old Mentzer finished a controversial fifth, and, in the aftermath, retired. He seldom even trained again. Mike Mentzer died in 2001 at 49.

But Heavy Duty endured. Mike Mentzer’s workout philosophy was adopted by Dorian Yates, who won six Mr. Olympia titles in the 1990s. Heavy Duty books and courses continued to sell. Workout frequency fell, workout intensity rose. Mentzer’s high-intensity has influenced other training programs, like Doggcrapp and Max-OT. And countless weight-trainers around the world continue to go heavy for brief, brutal Mentzer-inspired workouts. Over two decades after his passing, Mike Mentzer’s workout system lives on.


? Divide your body parts into two workouts, and allow 48 hours between workouts. For example, do workout A on Monday, B on Wednesday, A on Friday, B on Sunday (or Monday, if you prefer to take weekends off).

? To maximize recuperation, workouts follow the push-pull system: pushing muscles one workout, pulling muscles the other workout. However, because there are only two workouts, Mentzer modified this to include legs on push day and shoulders on pull day.

? Do 1-3 warmup sets before working sets. Do your last warmup with approximately 75% of your working weight and stop before reaching failure.

? Go to full-rep failure in the 6-8 rep range. Try to grow increasingly stronger in this range.

? Utilize pre-exhaust supersets. For example, flyes (which isolate the pecs) are done immediately before incline presses (which work the pecs with the shoulders and triceps), so that the “exhausted” pecs work to their fullest and give out first during the presses.

? Always maintain proper exercise form.

? Extend sets beyond failure with forced reps, negatives, and rest-pause.

? Train with at least one partner. Assist each other in going beyond failure.

mike mentzer curls
It takes two spotters to help Mentzer go beyond failure on 225-lb. barbell curls.


This is a Mike Mentzer Heavy Duty routine, circa 1979. After he retired, Mentzer prescribed increasingly lower volume—eventually as little as only one or two all-out sets per body part every two weeks! The workout included here best represents an effective and practical Heavy Duty routine. Warmup each exercise as necessary, and push these working sets to full-rep failure at 6-8 reps and then beyond failure via forced reps, negatives, and/or rest-pause for 1-3 additional reps.


Leg Extension — 2 sets x 6-8 reps

↕️ superset with

Leg Press — 2 sets x 6–8 reps

Squat — 1 set x 6–8 reps

Leg Curl — 2 sets x 6–8 reps

Standing Calf Raise — 2 sets x 6–8 reps

Calf Press — 1 set x 6–8 reps

mike mentzer workout
Old school and Heavy Duty: Mentzer calf pressing.

ANALYSIS: Here we see the first of Mentzer’s pre-exhaust supersets: leg extensions before leg presses. Also note that he does squats after the leg extension and leg press superset. He does the same reps (6-8 to failure + 1-3 after-failure) for even body parts like calves, for which many bodybuilders do higher reps.

Dumbbell Flye or Pec-Deck Flye — 2 sets x 6-8 reps

↕️ superset with

Incline Barbell Press — 2 sets x 6–8 reps

Dip — 2 sets x 6–8 reps

ANALYSIS: A pre-exhaust superset for chest: flyes before presses. And Mentzer again ends with a compound exercise: weighted dips.

Pushdown — 1 set x 6-8 reps

↕️ superset with

Dip — 1 set x 6–8 reps

Lying Triceps Extension — 2 sets x 6–8 reps

ANALYSIS: After legs, this is a push workout, working triceps after chest (two pushing body parts). Triceps start with another pre-exhaust superset.


Machine Pullover — 2 sets x 6-8 reps

↕️ superset with

Close-Grip Underhand Pulldown — 2 sets x 6–8 reps

Barbell Row — 2 sets x 6–8 reps

mike mentzer workout diet
Forced reps on Nautilus machine pullovers.

ANALYSIS: Of course, Mentzer starts with another pre-exhaust superset, this time doing machine pullovers (which target the lats without the biceps) before underhand pulldowns (which work the lats and biceps). Nautilus machine pullovers were also a favorite of fellow HIT-man Dorian Yates. If your gym doesn’t have a pullover machine, you can substitute, straight-arm pulldowns or dumbbell pullovers.

Machine Shrug — 2 sets x 6-8 reps

↕️ superset with

Upright Row — 2 sets x 6–8 reps

mentzer workout
Heavy Duty! Mentzer shrugs the Universal machine weight stack and bodybuilder Casey Viator.

ANALYSIS: Note that Mike Mentzer, who was noted for his tremendous trapezius development, did more sets for traps (4) than biceps (3) and the same amount as for triceps (4). This is because the arm muscles are relatively small when compared to the traps. We have another pre-exhaust superset: shrugs (which work only traps) before upright rows (which work traps with medial delts and biceps). Mentzer preferred to do his shrugs on a Universal machine, but you can use a Smith machine or free weights.

Side Lateral — 2 sets x 6-8 reps

↕️ superset with

Machine Shoulder Press — 2 sets x 6–8 reps

Dumbbell or Machine Rear Lateral — 2 sets x 6-8 reps

mike mentzer workout
Heavy Duty Nautilus machine side laterals

ANALYSIS: Another pre-exhaust superset: laterals before presses. Mentzer liked the Nautilus side lateral machine (Arthur Jones created Nautilus), but you can use any lateral machine or dumbbells.

Standing Barbell Curl — 1 set x 6–8 reps

Dumbbell Concentration Curl — 2 set x 6–8 reps

ANALYSIS: Finally, no pre-exhaust supersets for biceps. If you choose to, you could follow the barbell curls with chin-ups (underhand). Biceps is the last body part in what is essentially a pull workout—back, traps, biceps—though with the addition of deltoids.

For the definitive article about Mike Mentzer’s complicated, too-short life see: The Mike Mentzer Story