What Do We Know? What Don’t We Know?

I originally posted this to baye.com way back in July of 2004 after joining an e-mail discussion group for people teaching and using the SuperSlow high intensity training protocol. When I mentioned on my Facebook page I was updating and reposting some older articles I received a request specifically for this one, and managed to find it after a bit of digging. I have edited it somewhat for grammar and clarity, and added a few comments  in bold text.

Saturday, July 10, 2004

I’ve recently joined an online discussion group for SuperSlow exercise instructors and enthusiasts, and while much of the conversation has been your typical training and equipment talk, there have been a few debates over certain aspects of training which have been very productive, and a few others that have become a bit heated. I recently posted the following to the group, and wanted to include it here as I brought up several things in it which have been on my mind recently and I think deserve further discussion:

“I only recently joined the list, but I get the feeling there has been a lot of ongoing arguments here on various subjects for a while. I think it’s important that despite our own perspectives, experiences and biases we try to be as open as possible to new suggestions or perspectives, and consider them critically but objectively.

I have been an advocate of SuperSlow for a long, long, time, so much so that I’ve at times found myself more concerned with proving I’m right than with listening to what the other person has to say. Scientists don’t start an experiment to prove anything, they do it to discover something. As a matter of fact, the point of an experiment to attempt to disprove the hypothesis. We need to step back and consider whether we’re more caught up in proving what we think is right, or trying to discover where we might be wrong so that we can improve upon it. The more critical we are of ourselves and our methods, the more likely we are to be able to improve upon them.

Even things which may appear to be self-evident shouldn’t be immune to questioning.

Before we can argue about methods, we need to define desired outcomes. Since different people may desire different outcomes, we may find that we require different methods or applications of principles to achieve those.

We need to clearly and honestly distinguish between what we know and what we suspect so we have a better idea where to expend our investigative or experimental efforts. There are a lot of things I think we’ve taken for granted that need to be questioned.

Danny [Thompson] mentioned he believes Ken [Hutchins] is “way over-concerned with safety”. I have known and worked with Ken for the better part of the last eight years and agree, but the condition of many of the people he trains justifies it. The problem is when you try to extend that to everyone else. Based on things Dr. McGuff has written and my understanding of the nature of force, acceleration, injury, etc., I think the speed and performance of the turnarounds is far more important than the speed of the positive and negative excursions, and that even if you were to move as fast as four or five seconds in most movements you will not risk injury so long as your form is good and you perform the turnarounds slowly. We may find that speed of movement, like intensity, volume, frequency, etc. is something that must be tailored to the individual, with those who have injuries or conditions requiring caution are prescribed a slower rep cadence than those with a much greater structural integrity.

I worded this poorly. I do not think it is possible to be overly concerned with safety – safety should be one of the highest priorities of training. However, I think some overestimate the risk of certain exercises and methods to the average healthy person.

If, as I and a few others suspect, there is a benefit to repeated negative excursions after a particular degree of inroad is achieved, but it is also necessary to limit the TUL, then we may find that the ideal speed of movement from a safety standpoint or efficient muscular loading is not ideal for growth stimulation due to other factors requiring a greater amount of mechanical movement during the exercise. We may find that we have to compromise between moving slowly enough to reduce the force the body is exposed to and minimizing acceleration and increases in momentum during the positive, and performing enough repetitions within a particular time frame to allow for some minimum number of negative excursions during which micro-trauma can occur and growth stimulated.

This assumes that the model Ryan [Hall] posted for muscular growth stimulation is correct, and I suspect it is. However, like anything else, I’m going to remain open and critical of everything.

After reposting this I contacted Ryan Hall and received his permission to repost his biochemical model for stimulus and growth process of skeletal muscle. Ryan said that although the model is still correct some of the details are now better understood and he intends to update and expand upon this later. 

It is hard to do so, however, when in my own experience, Heavy Duty produced major size gains. So much so that I was constantly excited about it. In more years of SuperSlow than months of Heavy Duty, I have not even equaled that degree of muscularity. The only explanation for the muscular strength gains is that there are factors other than muscular size which contribute to force output that are improved dramatically by SuperSlow.

What do we know? What don’t we know?

We know that muscular work of a demanding nature is required to stimulate a response.

We don’t know the exact nature of how this is best applied to produce size or strength increases, we only suspect we do.

We know that too much work, or too frequent work, can have a negative effect.

We don’t know exactly how recovery works, or how to determine without a long period of experimentation how much or how little is ideal for someone or how it changes over time, we only suspect we do.

We know that progression is necessary for continuous improvement.

We don’t know the best method of progression, although we suspect we do. As for single vs. double progression, my own suspicion is that double progression only works because in the process people stumble across the best TUL for them every few workouts. Dr. McGuff wrote about this also.

We know that a reduction in acceleration is necessary to maintain a relatively continuous amount of momentum during the positive, which improves muscular loading. (We have to get away from saying “reduce momentum” because that is not correct, what we are trying to do is maintain a consistent momentum at a given level of resistance).

We don’t know how big of a difference this makes past a certain point, or just how slow it is necessary to move for just this purpose.

We know that moving more slowly allows for greater force production depending on an individuals level of motor control.

We don’t know how slowly is necessary for the average person or if there is any benefit to moving even more slowly from a nervous perspective.

We know that moving slowly reduces the force the body is exposed to and reduces the risk of injury.

We don’t know how slowly any individual must move for this purpose, and I suspect if we had massive amounts of data on injury rates associated with different repetition speeds and could cancel out other factors, we’d find it would vary from group to group depending on age and a whole host of other factors. If in doubt, it’s obviously best to err on the side of safety, but not so greatly that it is impractical [compromises size gains if that is the trainee’s primary goal].

For someone in good physical condition, a 4/4 repetition cadence performed with careful turnarounds probably provides a good margin of safety. Someone with osteoporosis or who is very deconditioned or who has a pre-existing injury may require a greater margin of safety and thus a slower speed.

If we find that prescribing rep cadence involves a compromise between efficient loading/safety and adequate mechanical movement to allow for micro-trauma (for the sake of argument – I suspect but I do not know) we may have to vary the movement speed based on the individual.

I still use a 10/10 protocol with some clients with certain spine or joint issues, but have been using a 4/4 or 4/3/4 protocol as standard with many clients for years with no problems and good results.

Studies show there is no significant difference in results between performing one set per exercise and two or three. While this might seem to indicate that one set is as good as two or three, and of course more time efficient, what does it say about overtraining? If two or three sets would result in overtraining, then why is there no significant difference? I suppose it would be necessary to read all of the studies and figure out exactly how they were conducted before going any further with this, but it’s something to consider.

I could go on and on. The important thing to consider here is that we must constantly question everything and not be so attached to a particular theory or method that we can’t be objective about it.

Drew Baye”

There is a tremendous amount we do know about exercise, but there are still many things which are not completely understood, so it is important to always remain objective and critical and to be open to new perspectives and information.

Since the principles of high intensity training are consistent with what we know to be true about biology and the physiology of how organisms respond to stress in particular, we know we’re on the right track. Since the use of slow, controlled repetition speeds is justified by both physics and biology from the standpoints of safety and efficient loading, we know we’re on the right track there also. We just need to continue to experiment and study the application of those principles while considering new information and ideas, to develop protocols or systems for prescribing them to individuals based on their unique physical attributes and desired results.

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31 Responses to What Do We Know? What Don’t We Know?

  1. Sandor April 22, 2013 at 7:30 pm #

    Posting this article shows that you are trying to be as objective and unbiased as possible, as always. You are not afraid to apply critical thinking or revise concepts, and this, again, earned my respect.
    Some questions:
    You mention in many of your articles that many factors (proper diet, rest, sleep etc.) are needed to achieve the best results, no matter what the goal is.
    Today I discovered an article on bulletproofexec.com (I don’t intend to advertise, feel free to clear the link from my comment if you want to) which cites a study according to which sleeping 5 hours/day is healthier than sleeping 8h. What do you think about this?
    My other question, not related to the previous one:
    Both me and my girlfriend have been doing high intensity resistance training 1x/week for several months now, and starting to feel and see the benefits of it. However, my gf’s last cycle, which is usually regular, got delayed this month by almost 3 weeks. He did some medical tests, the results were all ok, so I have a pretty strong feeling that HIT was the cause. What do you think? I must mention, that we are eating based on paleo principles, so diet should not be the cause. And no, she is not pregnant 🙂

    Thank, and keep up the good work!

    • Drew Baye April 23, 2013 at 7:25 am #


      I have not read the article on the BulletProofExec site, but will when I have time. I have read The Promise of Sleep by William Dement MD, PhD who is a leading authority on sleep and sleep deprivation and he suggests sleeping longer. Like most things, individual sleep requirements can vary due to many factors and your best gauge of how much sleep you need is simply how tired you are. If you’re feeling tired or drowsy, get more sleep.

      If there are no other health problems and the tests did not show any reason for your girlfriend’s missed period I wouldn’t worry too much about it, as long as she isn’t missing it regularly. Stress can cause this, and the physical stress of more intense training than she might be used to might be a factor, but this would be something best discussed with her doctor.

      • John December 20, 2013 at 8:48 pm #

        Hit once a week, plenty of rest, eating better, getting results, and a menstrual cycle timing change, it sounds like your girl friend is experiencing the results of testosterone elevation.

        • Drew Baye December 20, 2013 at 8:58 pm #


          Resistance training can increase testosterone and growth hormone, but I doubt it would cause enough of an increase in females to have a significant effect. There can always be exceptions, however, and a blood test would be interesting to see.

  2. Steven Turner April 22, 2013 at 8:30 pm #

    Hi Drew,

    A great article I am hoping that advanced technology may give us answers to prove what we know or suspect that we know is correct. We can only keep asking the questions.

    I am hoping that advanced technology will stop all the BS or the latest fad that many of the so-called experts in the fitness industry con the average person into believeing that they somehow need “for their health”.

    • Drew Baye April 23, 2013 at 7:51 am #


      We have learned quite a bit since I’ve written that, but there is still a lot that is unknown. A few weeks ago I wrote a comment about this on the FB page:

      “There are things we know we know (known knowns), things we know we don’t know (known unknowns), and things we don’t know we don’t know (unknown unknowns).

      The number of things about exercise we can put in the first category is much smaller than the second, and both combined are probably much smaller than the third. Anyone who thinks otherwise doesn’t know nearly as much as they think they do.”

  3. Alan April 23, 2013 at 3:32 am #

    Excellent post, thanks Drew. I am new to your site but from what I have read so far, I have found your insights and perspectives to be very rationale, objective and humble. Although, your training methodology including the SuperSlow protocol flies-in-the face of years of training for myself, I cannot disagree with the logic that you have supplied in your articles. Hence, you have gained my trust and look forward to reading more on your science-based approach to explaining exercise. One area I am particularly keen on hearing more from you on is your position that core exercises particularly on unstable platforms are not effective for training your stabilizer muscles and that this training (or any skill development acquired for that matter) cannot be transferred to other activities that require core stability and balance. Coming from a sprint canoe/kayak background, I’ve been training my core muscles for some time and when I first tried rowing as a sport, I found my balance to be above average for a novice rower. To give you another example, I have played tennis for most of my youth and when I started playing squash later in my teens, I was again able to pick up those raquet skills pertaining to squash at a much higher rate than most novices. This proved true again when I started to play badminton. I would love to hear your thoughts on that. Sorry for the lengthy comment.

    • Drew Baye April 23, 2013 at 8:26 am #


      This is addressed in the recent review paper Evidence Based Resistance Training Recommendations in the section Core Stability and Stable/Unstable Surfaces. The authors state,

      “…not only is there no significant difference in strength increases from training on stable and unstable surfaces, but there is also no evidence (or even a coherent theoretical rationale) for suggesting that weight training on unstable surfaces could enhance performance of specific sporting skills.”


      “The use of resistance training for enhanced function and sporting performance should be based on muscular strength adaptations, and not neuromuscular patterns including balance, which shows no transference.”

      The article The Myth of Core Stability goes into even more detail.

      While your core training may have contributed to better trunk muscle strength which would have helped you in these sports, it was neither necessary nor advantageous to perform those exercises on an unstable platform nor did it improve your balance in other activities. The same results could have been achieved more safely and efficiently with basic trunk exercises on a stable surface or using a machine.

      • Trace April 23, 2013 at 1:25 pm #

        Thanks for making these points. In my view these notions are the primary cause of confusion for the public and misapplication of known principles. The “SAID” principle (specific adaptation of imposed demand)is consistently ignored by trainers who should know better – or do know but would rather sell a new product. Ken Hutchins has written: “Balance is a specific skill that, if developed on a balance ball, would apply only to the balance ball.” In other words, recognize the difference between gaining overall strength and practicing a skill.

    • Craig April 26, 2013 at 10:19 am #

      Just a personal anecdote: Normally, I do overhead presses with dumb bells from a seated position. I feel that it does let me focus more on the targeted muscles. However, last year, for a stretch, I instead used a standing overhead press with a barbell. The first few times I did this, I woke up the next day to find my abdominal muscles were quite sore, as if I had been doing a lot of planks or crunches. Clearly, by doing the exercise from my feet instead of my butt, I was engaging additional muscles. Was this good or bad? I doubt there is a clear answer.

      I will note that the traditional nautilus training circuit involved lots of different machines (10 or more), each designed to target/isolate a particular muscle group. The more common practice today in SS/HIT circles is to use fewer compound machines (big 3 or big 5). Basically you replace a larger number of isolated movements with fewer compound movements that exercise several muscle groups simultaneously. Conceptually, this is no different than replacing a leg press with a squat or a seated machine press with a standing overhead press in order to engage a greater number of muscles with a given exercise. The real question should be: Can the exercise be done safely and productively?

      • Drew Baye April 30, 2013 at 11:00 am #


        If you perform a standing exercise the trunk muscles will be involved to a greater degree than if the same exercise is performed from a seated position, but at the expense of reduced ability to focus on and effectiveness for the muscles primarily targeted by the exercise. There is a trade off between how many muscle groups are involved in an exercise and how intensely and efficiently you can work any particular one, as well as safety considerations depending on the exercise. As a general rule you should perform exercises designed around muscle and joint function, not locomotor, sport, or vocational movements, but the specific exercises you should perform depends on other factors including your goals, your current physical condition and abilities, available equipment, etc.

  4. Matt Nairn April 23, 2013 at 8:42 am #

    Hi Drew

    I did some reading on Mike Mentzer’s approach and he used the superset, for example – Leg Extention followed by Leg Press, followed by leg curl
    Or Pec Deck followed by Incline Bench.

    Do you think this method is too much volume per body part, I know you and McGuff prefer one set – but can supersets like this be appropriate for some clients?



    • Drew Baye April 23, 2013 at 8:47 am #


      Pre-exhaustion and supersets have their uses. I write about pre-exhaustion and include it in some of the workouts in High Intensity Workouts.

  5. Leo April 23, 2013 at 9:01 am #

    Thanks Drew.

    Do I take it that you do not regard superslow as effective for muscular hypertrophy?

    • Drew Baye April 23, 2013 at 9:07 am #


      Superslow is very effective for muscular hypertrophy when done with an appropriate load and rep range, it just isn’t absolutely necessary to move that slowly.

      • Ben Tucker April 26, 2013 at 9:51 pm #


        Do you still hold the same view as 10 years ago that Heavy Duty creates better size and gains compared to SuperSlow?

        If so, has this created a rift between you and Ken?

        • Drew Baye April 30, 2013 at 11:23 am #


          I don’t think there is as big a difference between different HIT methods as some do, and although I disagree with Ken about optimal time under load we get along fine. Ken is still one of my favorite people to talk with about exercise.

  6. Ian April 23, 2013 at 2:36 pm #

    Another great post Drew, thanks.

    I have been thinking of ways to get my wife interested in strength training but I think she might need a female prespective. Is there any female bloggers that you would recommend that follow the BBS or HIT protocol? I have found some but mostly into crossfit.


    • Drew Baye April 24, 2013 at 5:04 pm #


      I don’t know of any female bloggers writing about HIT or BBS, and although there are a lot of female subscribers to my newsletter and a few on the forum they tend not to post as much.

    • Ben Tucker April 26, 2013 at 10:12 pm #

      My wife could never get into the gym scene either. That’s probably a good thing. But I’ve always held in high regard women who exert themselves and thus look great because of it.
      I oversee my wife’s weekly HIT routine and, although she hates the exertion, she enjoys the time saved. If it weren’t for HIT, she would’ve fizzled a long time ago. She’s just not one of those “fitness types.”
      It seems you either love to stay active or you don’t . I’ll give you this tip, though: If your wife is overweight (like mine was) no activity in the world is going to make much difference unless they control their daily calorie intake. As soon as mine applied that knowledge, 40 lbs came off in 5 months. Through portion control, it has stayed off.
      I don’t know if you’ll be able to contact her, but check out Stephanie Arnold BBS workout on Youtube. There’s also a vid of her in (I think) her 3rd trimester doing a HIT workout. Very impressive.

      • Drew Baye April 30, 2013 at 11:25 am #

        Thanks Ben, I’ll look for her video.

        Exercise is an important part of a fat loss program, but how much fat is last is almost entirely a matter of diet.

      • Ian April 30, 2013 at 12:07 pm #

        Ben Tucker,

        Thanks for the great information. My wife and I have been pretty good diet wise, both believers in a clean “paleo” diet. I was able to convince her of the benefits of this diet, and it has really worked for both of us. I might try to show her Skyler Tanner’s talk on the bio markers of ageing, as it shows the additional benefits of strength training over and above fat loss. Based on my results from HIT I hope she will see how it works when done properly. It is really a shame that women don’t strength train more.

      • Ian May 15, 2013 at 12:41 pm #

        Ben Tucker,

        I find that my wife, like most women, seem to be completely turn off with weight training. I won’t speak for most women but my observations are that women will try almost any kind of different excercise program (all the fads) but won’t touch intense weight training for fear of becoming completely muscle bound after one excercise.

        How did you convince you wife to lift with you? I am hoping to convince her of the long time benefits of increasing muscle mass.

        • Drew Baye May 18, 2013 at 7:06 pm #


          Whenever I talk with women about exercise I assure them they will not become overly muscular because they lack the necessary hormones, and that a proper resistance training program and diet will do far more to improve their physique than anything else promoted for that purpose, more quickly, more efficiently, and more safely.

  7. Steven Turner April 23, 2013 at 7:06 pm #

    Hi Drew,

    Thanks for the response – the knowns and unknowns are classic I have to write that statement down.

    For Allen, some thirty years ago I was a Physical Training Instructor in the Royal Australian Navy before “core” was heard of. The course required me to be super fit and quickly learn a lot of knew skills that I had never done before. Canoeing was one of those skills, I learnt to balance by getting in the canoe, fall out a few times. There was one particular gymnasitic skill I had to learn which required a strong “core” I asked one of the instructors an exercise to strengthen my “core” his reply was “practice the skill” – that was said to me over thirty years ago.

    I taught boxing for many years whilst a strong ‘mid-section is essential, balance in boxing is getting your feet in the right position, if your feet aren’t in the right position you can forget about your mid-scetion.

    The “core” is overrated the best advice strengthen all the muscles in the body and specifically “pratice the skill”.

  8. Wayne April 24, 2013 at 11:10 am #

    Hey Drew,

    I’ve been following your site and emails for a while. Do you have any insights into post-surgery rehab like say for rotator cuff surgery or ACL surgery? I’m into my 7th week of rehab for rotator cuff surgery and I’m wondering if HIT could be applied to the resistance training I’ve just started doing per my doctor’s and physical therapist’s protocols?

    I follow an HIT routine working out once per week. I chuckle to myself when the PT tells me to do my shoulder exercises in 3 sets of 10 reps. I don’t want to damage the shoulder repair but I haven’t seen any material discussing using HIT post-surgery.


    • Drew Baye April 24, 2013 at 5:07 pm #


      The same principles you would use during regular exercise are applicable for rehab. Range of motion may need to be reduced to avoid painful positions and in some cases the way the movement is performed may need to be altered slightly, but this would be something which requires hands on work with someone to determine.

  9. Ian Wilson May 9, 2013 at 10:22 pm #

    Hi Drew
    I train at home so i’m limited with the equipment I use. I do box squats using the super slow method of training as I have a pre existing back
    problem. While they are effective, I have much better success using a 4/4 cadence with minimal loading. Have you ever considered making a video of one of your workouts that demonstrates the most effective cadence to use to perform each exercise?

    • Drew Baye May 11, 2013 at 4:17 pm #


      I plan to shoot exercise instruction and demo videos to post in the members forum over the next few months.

  10. Dan Hawkins May 11, 2013 at 11:19 pm #

    I just found your website. I grew up in the 70’s using Nautilus and their philosophy. I now have access to Hammer Strenght equipment but I can not find any mention of Hammer Strength on your website. It seems logical to apply Nautilus training principles to Hammer Strength equipment. They are similar in design. Your thoughts and recommendations.

    • Drew Baye May 12, 2013 at 12:23 pm #


      The same principles apply to Hammer Strength, Avenger, Pendulum, and other plate-loaded machines. The Hammer Strength equipment actually started out as the Nautilus Leverage Line, but in the late 80’s Arthur Jones’ son Gary, along with Kim Woods and Pete Brown took the designs they were working on and started Hammer Strength.

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