High-Rep Leg Presses on a Duo Squat; Rep Range for ST Fibers During NA Exercise

Dr. Darden, I have two questions:

  1. During one of the Nautilus seminars in 1982-1983, Jones argued that by their nature thigh muscles are built for endurance, and therefore, they may require one all-out set of 100 reps (50 reps each leg) on a Duo-Squat machine, if one can tolerate it. Later on, in his article “Exercise, 1983… the Possible and the Impossible - Part 1” he continued with that idea. Quoting: “Starting immediately, I am going on a program that consist of only five exercises, and I will stick with this program for a period of several months; performing only one set of each of the five exercises during each of three weekly workouts… workouts that will require about fifteen minutes each; a total training time of less than one hour weekly. The first exercise will be squats performed on a Duo-Squat machine, using as much weight as possible and working up to one-hundred repetitions before increasing the weight… fifty reps each leg”. Question: do you know if Jones were able to evaluate the effectiveness of this approach? Has he changed his mind later on the subject, or not? Am I right that he meant doing the set in a rest-pause fashion (let’s say, doing 20 reps straight, brief rest of 5-10 seconds, another 10-12 reps, rest again, another 5-7, and so on until you do singles, but reach 50 each leg or whatever the number)?

  2. A set of leg extension done in negative-accentuated style is commonly stopped when you can’t lift the weight with both legs. It should take 5-7 reps by each leg before it happens. In my case of slow-twitch thigh muscles, I can do 20+ reps each leg on a MedX leg extension machine before I can’t lift the weight with both legs. If I try to increase the weight in order to fit into the general guideline of 5-7 reps each leg, I definitely can’t control the weight during the negative portion. Question: should I assume that general guideline of 5-7 reps each side was for mixed type of fibers and doesn’t fit slow-twitch fibers, for which a higher rep range will still be better, subject to I can control the negative and stop the set when I can’t lift the weight with both legs?

  1. I never asked AJ, in his later years, if he still thought 50 reps per leg on the Duo-Squat was the best recommendation. I suspect he would say it was too many.

  2. I believe your assumption is correct.

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I think doing that many reps, The lactic acid and cardiovascular fatigue would be the limiting factor rather than your muscles themselves

Post hip replacement surgery at 65 years old, I turned to high rep leg presses. My surgeon told me not to lift or walk with more than 100lbs. I decided to try 2 minute leg presses, aiming for 60 reps, pacing myself at 15 reps every 30 seconds.

I was determined to do 60 reps regardless the time required. It was “fairly easy” to get to 45 reps by 90 seconds, but it usually took me 40 to 45 seconds to finish the final 15 reps. I was doing full range of motion, thighs down by the sides of my torso. After 60 seconds my quads would begin to burn, by 90 seconds the quad burn would subside, and a glute and hamstring burn would intensify throughout the final 15 reps that were slowing every rep.

At 65 I was in the throws of sarcopenia, as my vastus muscles were wasting from the insertion and heading upward.

My assessment of the 2 minute leg press was that it was extremely demanding, but more so muscular (maybe endurance) than cardiovascular. But it was demanding cardiovascular too. If I were young, I believe it might have been beneficial to incorporate the 2 minute leg press once a month during a deload week.

Thank you, Dr. Darden.

I do squats in Squatmax-MD in high density rest-pause cluster fashion doing 50+ reps. I remember Steve Reeves advocating 100 reps squat with weight on the bar matching your body weight . Apparently, done also in a rest-pause style. My thighs tend to respond to such load and higher rep range better than we I do 10-20 reps. 3 min challenge on a Duo Squat devised by Dr. D was a good one too. I don’t have access to a duo squat machine anymore, though

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It would seem to me that you are actually putting more load on the hips by doing the fast reps than by slow reps with a heavier load. I agree with the 2-Minute Set part, just maybe with 20-30 reps, not 60.

For hip joint protection I don’t consider rep speed as a factor, but more focused on weight and impact as variables to adhere to. That said, 15 reps every 30 seconds is not fast. I will admit it is a moderately fast tempo, where fast is 20 reps in 33 seconds (which is a part of my current leg press program.)

About 4 years ago I changed my 60 reps in 2 minutes to 20 reps in 2 minutes, where I stay at a single rep in 6 seconds pace, where I do a 5 second negative with a pause, followed by a positive as fast as I can push. I still do this at least one set a week. I also do a 30-10-30 leg press for 2 sets, twice a week for 2 sets for a period of about 3 months instead of the 20 reps for 2 minutes.

I’ve long been a fan of the 20 rep squat routine but a couple years ago the indiscretions of my misspent youth (ankle problems) had me in pain. I decided to go lighter for higher reps. Now once a week I do 100 rep squat set with 60lbs. I feel like I’ve lost some size (I was never big anyway) but my ability to hike steep hills has significantly improved. I live in Florida and am section hiking the Appalachian Trail , While the hills are tough, I don’t have near the problems I used to have and occasionally even out hike others.

Only on the uphill though. The ankle issues really slow me down on the downhill.

This is disinformation, Brian Johnston, IART, Mikesky, et, al debunked this years ago. As long as ballistic or explosive style reps are not used, there is statistically insignificant increases in force between SuperSlow rep speed and 2/4 rep speed. Darden even uses 1/2 rep speed. There is little reason , especially to lessen injuries, to intentionally slow rep speed below 2 seconds on movements such as a Nautilus Duo-Squat machine.

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Mike and Ray tested out the “high reps for legs” theory in the 90’s. They found mixing cardio with muscle building delivered less than optimal results. 12-20 is sufficient.

Could you provide a reference to an article or a book? I vaguely remember it being mentioned, but I can’t trace the source. Both Mentzer brothers were blessed with fast-twitch muscles with resulting enormous strength and their preferred choice of a limited number of exercises for a muscle group and low rep range. Not sure what kind of research they did on this subject and who were the participants. Thank you in advance.

I agree with all that, but he was talking about 1/1 Reps!! With that quick a negative and positive, there’s bound to be some “bounce” at the bottom. And there’s 200 lbs becomes 400 lbs +

I would disagree unless you are doing plyometric reps in the negative.
Even on fairly fast reps the muscles are loading up during the descent, thereby making the near sudden change of direction of little more stress than the rest of the positive. This is my opinion based on 54 years of lifting weights.

No reference, but Mike Mentzer told me in the mid 90s he and other HIT trainers found higher reps better for legs. Hence, the 12-20 reps versus the 6-10 reps for everything which was originally stated in Heavy Duty I and in my initial phone consult with him in 1993.

Higher Reps for Legs?

Q: I recently purchased the book you wrote with Mike, High Intensity Training the Mike Mentzer Way, and I love it! I’ve already read it through twice and am making progress at each and every workout. My question is, why did Mike advocate higher reps (12 to 20, on pages 134 and 135) for the legs and lower reps (6 to 10) for the upper body?

A: Thanks for your kind comments about the book. The reason Mike advocated higher reps for leg training is explained by random genetic variation within an individual’s neuromuscular system. Research conducted during the early 1980s by Arthur Jones and associates at Nautilus Sports/Medical Industries (NSMI) in DeLand, Florida, corroborated Mike’s view to a large extent. It indicated that the lower body requires a different type of training than the upper body. Mike once wrote about that discovery:

‘NSMI found that the neurological efficiency of the legs, the number of muscle fibers activated during a maximal contraction, is extremely low. The neurological efficiency of the muscles in the upper body is considerably higher. Activating more muscle fibers in a maximal contraction involves more oxygen and lessens the muscles’ endurance. Developing a muscle maximally requires regular stimulation of as much of the bulk of the muscle as possible.

‘If you regularly stimulate 25% of the fibers in a muscle, that muscle will grow to a certain size. Stimulating 50% of that muscle’s fibers would certainly result in more growth. Since a very small percentage of the thigh’s muscle fibers are activated even on a maximum contraction, it would seem logical that the thighs require high reps to stimulate a high percentage of the fibers.’

That intrigued Mike, and he began to look into how many reps, ideally, should be used for leg training. I also recall that Ray Mentzer looked into the issue of performing higher reps for the legs and came to similar conclusions:

‘Why so many reps [for the legs], you ask? Well, there are many reasons, but the basic one is this: Neurologically, the thighs have a much different pathway. If the leg or thigh neurons’ firing rate was the same as that of your arms, delts or chest, you wouldn’t be able to walk any distance. Do you ever get writer’s cramp? Just think if you had that same firepower in your thighs. You wouldn’t be able to get to your front door or climb steps. The thighs and legs have a structure that’s neurologically designed for endurance, for long, heavy, arduous tasks. So overloading as heavy as possible for 10 to 20 reps will work much deeper fibers. Some people even do as high as 50 repetitions, I’ve even heard of up to 100, getting good results from only 1 set!’

Mike went on to conduct informal tests on various high-repetition schemes, as the NSMI research was only preliminary in the 1980s. He began by dramatically increasing the number of reps he did on each of his leg exercises. Whereas in the past he’d performed 6 to 10 reps, he upped it to 50, with the last rep being as close to failure as possible. He wrote:

‘Your cardiovascular system will adapt to the increased demands so that you can move an appreciable weight to an approximately 50-rep failure. At that point try 75 reps per set, then 100 and beyond, but be sure to carry each set close to or actually to failure, and don’t do more than 2 sets for the thighs.’

Even so, Mike found that past a certain threshold, performing higher reps had little to no effect on stimulating additional muscle growth. When he trained with repetitions above 20, say, 50 to 100, he was dividing the stimulus for adaptation between the aerobic (endurance) pathways and the anaerobic (or strength-and-size-building) pathways, compromising the muscle building effect in favor of the endurance-building effect.

By the 1990s Mike was not in favor of such excessively high-rep sets (if, indeed, he ever was), having experimented and not been duly impressed. He often said, 'Bodybuilding is not aerobics, and that you should train anaerobically, that is, with high intensity and brief duration, to keep the training stimulus solely within the anaerobic pathways so that you don’t compromise your efforts. As such, he noted that performing reps beyond 20 was not only unnecessary but actually counterproductive.

Mike did hold, however, that the neuromuscular efficiency of the arms, for example, was much greater than the legs; so while you could thoroughly stimulate your biceps and triceps with a repetition protocol of only 6 to 10, the legs, by contrast, required more, the range of which he placed at 12 to 20, with 20 being the absolute top end. On all sets, however, whether for the legs or any other body-part, Mike said that the key was to train with the highest intensity of muscular contraction you can generate and to take each set to a point of muscular failure.

Opinions are always and always will be all over the place so I guess it’s whose advice you decide to go with first . When that doesn’t work like you expected , you try the other and eventually find out what works best for you. I value everyones experience and opinions .

Just the other day I saw CT answer the old rep range question about higher reps required for legs and his response was …

" There isn’t. Some people think that the legs need higher reps to grow, and that is absolutely unsupported by science and logic. Heck, I personally always progressed better from lowish reps on lower body. "


Brad Schoenfeld has the same opinion.

On CT forum there is a topic ‘Is Lifting Heavy Still Worth It ?’

This reply I think is the fifth down ( marked 5 days I believe ).

No one does anything faster than 1/1 on a Nautilus Duo-Squat machine. Even the Mentzer boys with Boyer did 1/1 rep speed at Nautilus. If a one second concentric rep speed is not dangerous, then a 1 second eccentric should be fine also, as one is much stronger there, and the molecule Titin provides elastic recoil protection. hiT beat rep speed to death, and the chickens came to roost. Bodybuilders by and large do not even do full ROM, yet get huge on mid hrange reps at 1/1 or less. Show one long term progress report of advanced lifters doing SuperSlow. They all look like they do not lift weights at all,


I have to agree. About 1/1 cadence is my personal sweet spot for lifting. I control the weight, but I don’t focus on rep length. Obviously the reps right around failure are slow, as I grind through the rep. I think this allows me to use heavier weights and has been very effective for building muscle. Over time, I believe this has become the most tried and true cadence for building muscle.