THE big questions in the world of strength and conditioning:  the efficacy of utilizing explosive movements in the pursuit of athletic betterment, calories vs “content” vis-à-vis weight gain/weight loss, the single vs multiple set debate…; now if it weren’t for pressing issues like these, exactly what, pray tell, would we Physical Culturalists have to argue about?  I mean, a good 40% of the world’s internet traffic would just up and die  🙂

The problem (such as it is) with these debates is that most times the debate itself is force-framed into yes/no, black/white, right/wrong ideological camps, with each side having hunkered into a “no quarter asked, no quarter given” mentality.  This, quite simply, is no way to tackle any issue that so heavily turns on context and scope, and that is so mightily effected by a multitude of variables that simply cannot be effectively accounted for, much less controlled.

For instance, this recent post in Exercise Biology, along with the referenced studies (here and here) would seem to suggest that multiple sets to failure (in this case, three at 70% 1RM) are more conducive to hypertrophy than a single set (again at 70% of 1RM) taken to failure.  Ok, fair enough – but let’s dig a little deeper and see if we can uncover more to this story.

Now I’m in no way a tunnel-visioned worshiper at the altar of single-set-to-failure, BBS/HIT-like exclusive training; I do remain somewhat agnostic on matters of one protocol vs the other, opting instead for the utilization of the right tool for the particular job at hand, given the peculiarities of each unique circumstance. It is my opinion, for instance, that one can get a fantastic workout, and realize great results, with little more than bodyweight, gravity and basic playground equipment.    Is this necessarily an optimum way to induce a growth stimulus?  Is it time efficient, safe, and all-encompassing?  Well, in a word, no – but if this is all you have to work with and you’re willing to invest the requite time, you can certainly expect to realize some pretty good results.  Not optimum results mind you, but some pretty good results nonetheless.  And some (myself included), freaks that we are, would even consider this type of activity recreation, a really cool way to spend a couple of hours on a pretty day.  Enjoyment of an activity, however, does not imply that it is necessarily the most efficient way workout, and we need to – if not act on this distinction – at least acknowledge it. 

But back to the post and referenced studies: first off, in my mind I believe that there is a huge difference between localized and systemic stimulus.  A HUGE difference.  In other words, in no way does a single-set-to-“failure” in a unilateral leg extension impart the same systemic stimulus – thereby signaling a much more pronounced and universal growth/protein synthesis signal — as does a bout of full-on BBS/HIT-like training.  The two simply cannot be logically compared.  So researchers, in my humble opinion, need to do a much better job of comparing apples to apples, as this particular study is akin to dropping an accomplished 100 meter sprinter in an 800 meter race, then proclaiming that the winner (who’ll assuredly not be the 100 meter man) has trained in a manner that is therefore superior to that of the 100 meter specialist.

Another way of looking at this is to say that sure, a single set of push-ups to failure is not as effective a training stimulus as multiple sets to failure.  So what is the limiting factor here, and why would multiple sets be required?  The short answer is intensity, coupled with the ability to impart a deep inroad (muscular fatigue), both locally and systemically.  As Louie Simmons is fond of saying, you’ll never invoke a response by simply tossing BBs at an elephant’s ass.  To carry this metaphor out just a bit further, you better pack that BB buckshot behind one hell of a powder load (i.e., ramping up intensity via multiple sets), or – and much more preferable, in my opinion – nail the poor bastard with a single bazooka round; an intense, deep-inroad, single-shot dose of growth-promoting stimulus.  That’ll no doubt get the elephant’s attention, and quick.

And then there is the matter of pinning down those pesky little variables, things like “intensity”, and “failure”.

Now it’s blatantly obvious, to those of even limited training experience, that the term “unilateral leg extension” is in no way synonymous with anyone’s definition of “intensity”.  Check this prior post, and the embedded video clips therein, for an example of a whole-body, BBS/HIT-like workout that is both brutally intense and a potent driver of systemic hormonal growth response.  Intense?  Are you friggin’ kidding me?  Failure?  Complete and utter.  The ability to perform another set in any of the exercises performed in this session?  Yeah, right.  Note: the one problem with attempting to capture just how much intensity a trainee (in this case, me) is pouring into any machine is that there is nothing to gauge that intensity against; no wobbling plate stacks, no flexing, heaving bars, nothing against which to gauge bar speed and power output.

Now, to put this level of intensity in prospective, the BBS/HIT/SS bout that I engaged in here took all of 15 minutes, start-to-finish, to complete.  Even with superior recuperative ability – which I possess, not by virtue of anything that I’ve done myself necessarily, but just by luck of the genetic draw – I doubt that I could progress, let alone pull-off, one of these workouts at a frequency interval of anything less than 5 days, as doing so would keep me permanently mired in recovery purgatory (otherwise known as overtraining hell).

So compare that workout’s level of intensity and systemic “dosing” to what I am able to accomplish using the tools I have access to – primarily, free weights: a “normal” iron session for me will take approximately 45 minutes to complete, and I hit, on average 4 such sessions per week.  And there’s a much different dynamic involved here as well; going to true and utter failure while using free weights in a compound movement is simply not a safe nor is it an advisable thing to do and, therefore, multiple sets are required to impart a sufficient inroad.

Intensity, volume and Time Under Load.  Goals.  Available tools.  Circumstance.   These are the variables that one must juggle so as to craft for himself an appropriate protocol.  One size does not fit all; the dogma is that there is no dogma.  Craft wisely, then proceed with confidence.


  1. Fascinating stuff.

    Richard Dawkins has a great phrase I like to trot out: The Tyranny of the Discontinuous Mind. What this basically means is, we humans have a cognitive bias to only see concepts and theories as black and white vs. shades of gray.

    I know I’ve swung back and forth on many issues: low-fat vs. low-carb, calories count vs. hormones count, etc., and I always end up somewhere in the middle. Both theories are right to a certain extent, and vary drastically based on context.

  2. To be fair, I wouldn’t be training you in that short of crushing HIT fashion were you a client. You’d get negatives every workout if you were like Casey Viator: detrained, living in a lab, and only sleeping, eating, and training!

  3. It is amusing that other work shows no difference between one set and multiple sets. When you answered Vicki’s recent question you linked to the Conditioning Research blog which in turn linked to a paper claiming a review of the literature does not support multiple sets as optimal for strength gains ( The paper linked to by the article above looks at hypertrophy, not strength, however one can easily find reviews supporting multiple sets for strength (e.g. If the exercise scientists cannot consistently interpret their results in the same way it does lead one to question the rigour of the whole field.

    • Which, in my mind at least, seems to indicate that such highly important variables as (including, but in no way limited to) “intensity”, “failure” and “perceived level of difficulty” — not to mention genetics and biochemical/hormonal milieu — simply cannot be accurately accounted for. This is why training can never be a “paint-by-numbers” activity. This is an endeavor that is as much about art as it is science. In fact, the longer I’m in this game, the more credence I give to the “art” side of the equation; art tempered, that is — where applicable — by thoughtful science. Or as Richard Feynman, Nobel Prize-winning physicist so eloquently put it:
      “It does not matter how smart you are, who made the guess, or what his name is – if it disagrees with real-life results, it is wrong. That is all there is to It.”
      What matters in the real world, ultimately, are n=1 results.

  4. Confirmation bias runs rampant in health and fitness circles especially. Keith you’ve consistently alluded to this and it’s taken a long while to sink in; especially for those of us whose only trainee is themselves. The success that the individual is CURRENTLY enjoying can be so darn exciting that it colors all other input.

    Darrin said, …”low-fat vs. low-carb, calories count vs. hormones count, etc.,” Boy does that resonate. The first 85% of my fat-loss was achieved via low carb and believe-you-me I let everyone know that “calories don’t matter!”. But in order to go from 4-pack to six I finally had to relent and admit to myself that calories do matter and a lean mid-section requires dialing in easy to over indulge in foods like butter and coconut oil.

    Anywho, another thought provoking post Keith. Gracias.

    • Yep, at 20% bodyfat, calories are of very little importance; plunge down to the single-digits (low teens for females), and it’s a whole different story.

  5. Keith,

    Great post. I totally agree. I think that the folks doing 1 set to failure(that they found inferior to multiple sets to failure) were definitely not doing BBS/HIT. The last thing I am thinking of after my BBS set is getting on the machine and doing it again for several days. If it would take you 5 days then it is 7 or more for me as I don’t have the wolverine gene.

    If you aren’t going to take the intensity up then one set will for sure not be enough to achieve the same level of inroad. Bottom line is no one, even me, will believe it until you actually do it. Chatting hypothetically won’t get you there. You need to experience what a real BBS/HIT set to failure is to see that multiple sets aren’t going to happen unless you use a different protocol.

    Good stuff,


    • An absolutely spot-on observation. There is just no way to adequately convey just how intense these BBS/HIT machine-based sessions can be. One has to actually “try one on for size” to really grasp the idea. I’m certainly no stranger to intensity, however, there is a limit to how far I can safely push myself with the basic tool set that I have access to. And many folks with access to the same limited tool set just cannot comprehend what it is like to be allowed the freedom to push so far and into such a deep inroad. It’s just not possible with free weights; great tools, free weights — but tools better suited for other applications. As tough/intense as my free weight workouts can be, and as much intensity as I pour into every rep, I still have to employ multiple sets to achieve decent inroad. The fact of the matter is that a much greater inroad can be achieved — and in a much-condensed period of time — if one has access to proper machines and is willing to nail a BBS/HIT-like workout. I don’t think that free weights lend themselves particularly well to single-set-to-failure, BBS/HIT-like training, but that’s just my opinion.

  6. A very thought-provoking post (and comments). Thanks very much from a new reader of your blog. I do have a question about how you and your readers conceive of ‘HIT”. I do a modified version (with free weights and cable exercises) but I do not go to absolute failure, stopping instead when my form begins to break down. In terms of ‘intensity’, I question whether absolute failure is necessary (and, therefore, I question whether machines – while they may have many benefits – are necessary to a HIT program. For what it’s worth, my own program usually results in two full-body routines with no more than one set per exercise (but, multiple exercises for larger muscle groups). To restate my question: what evidence is there to support the claim (and, I’m not sure you or your readers are necessarily making this claim) that ‘high intensity’ = absolute failure in a given set? Thanks,

    • Will, I’ve got a post in the works that I think will answer your question; in fact, I’ll reference your question.

  7. Keith Norris wrote: “going to true and utter failure while using free weights in a compound movement is simply not a safe nor is it an advisable thing to do”

    How true that is! All of my weight-room injuries, the worst being a compressed lumbar disc suffered while deadlifting, happened b/c I was trying to squeeze out that ‘one last rep’ to really push to failure.

  8. First off Keith, congratulations on the 2010 Top Fitness Blog Award. I’ve been out of the loop for the last few months due to my work demands and am still catching up.

    Next, it seems like every time I find myself questioning a protocol, or adrift with my exercise routine, I find either some clarity, motivation, inspiration, or education from your blog. Thanks and keep it up!

    • Cool, and welcome back, Andy. And thanks for the kind words as well. Remember, there are no “bad” protocols, per se, only bad applications.


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