Training to Failure?
Killer article by Lyle McDonald re: training to failure
Quote:
Why go to failure?
The question of how much stimulation (and what type) is sufficient to
cause maximal/optimal muscle growth is one that does not have an easy
answer. Many groups and individuals feel that going to the point of momentary
muscular failure (or beyond with certain techniques) is the key to causing
muscular adaptation. That is, taking the muscle to the point of attempting
the momentary impossible is the key ingredient to muscular failure.
There have been several schools of thought as to why going to failure is
necessary. One of those is the simple microtear theory wherby the muscle
literally undergoes physical tearing. Various individuals feel that going
to the point of ischemic rigor (where the muscle essentially locks up) causes
minute tears to occur in the muscle during the eccentric phase (the
lowering phase of a weight training movement) and that is the stimulus
for growth. If true, this is incedentally why the eccentric point of the
movement is both critically necessary for growth (for the most part)
as well as the cause of the majority of muscle soreness. That is, since
the tearing occurs during the eccentric portion, it seems reasonable to conclude
that one must perform an accentuated negative to get increases in size and
strength. Proponents of this theory offer as evidence the fact that
muscles stressed in a concentric only method do not undergo growth
consistently and that the eccentric portion of the movement has been
shown to be the stimulus for growth. However, they also feel that negative
only movements (which are often used to increase the intensity of
training since more weight can be lifted with eccentric vs concentric
contractions) do not work as well as combined concentric/eccentric
lifting as the concentric is necessary to 'prime' the muscle in some way
for the above mentioned microtears.
Now we do know that heavy training (especially eccentric contractions)
cause an increase in biochemical markers of muscle damage which lends
some support to the theory that muscle damage is a key stimulus for
growth. But, even this brings up the question of just how much muscle
damage is needed to stimulate optimal growth. This is not a question
that anyone is even close to answering at this point and I have a feeling
that it may depend on the person and their genetics (which might explain
why some individuals can grow from greater amounts of training while
others overtrain with anything but the least amount).
Now, at this point in time, there is not adequate data to say exactly what
it is about lifting a weight X number of times that causes it to grow. Various
other theories have been offered instead of the above including ATP depletion
(which, at least during high intensity cycle ergometry has not been shown to
occur), CP depletion (which, if correct would argue against creatine loading),
decreased blood flow (which occurs as a result of near maximal muscular
contractions which cause capillaries near the muscle to collapse), increased
blood flow (i.e. the pump theory of growth), muscle ischemia (oxygen
deprivation but we don't see huge muscles in individuals who spend lots
of time at high altitude) and the simple tension/metabolic work
theory (covered in great detail in a seminal review article by
Goldspink et. al.) that argues that forcing the muscle to do high intensity
work is the prime stimulus for growth.
Now we also know that involuntary high intensity contractions (like with
electrical simulation) does not cause growth except in very untrained or
injured inviduals. So, not only does there seem to be a need to perform
high intensity muscular work, it has to be generated by a person's own
nervous system to be effective.
Ok, so why failure? Is there anything special about going to muscular failure
which might be the primary stimulus for growth. Other than the microtear
theory which mandates failure so that the tears can occur, none of the above
theories seem to require going to failure. And, it may be that tearing can
occur without going to failure seeing as it does occur with downhill running
(which forces the muscle to contract eccentrically as well). But, we know
that long distance running doesn't spur muscle growth so there must be
something else going on.
Let's say you're lifting a load that puts you above the threshold to recruit
100% of your motor units (about 8RM for upper body movements and 15RM
for lower body movements). And, let's further say that you are performing
an upper body movement with your 8RM. Well, strict proponents of the
failure theory would argue that you must perform 8 reps to achieve growth
and that stopping short of this would not generate any growth. But, if
you were to stop this set at 7 reps (knowing with 100% accuracy that
it was your 8RM) you would achieve almost 100% of the (take your pick
here) ATP depletion, CP depletion, decreased blood flow, increased blood
flow, oxygen deprivation or time under tension. So, the question still
remains: Why failure?
Let's take as an assumption that the critical component to muscle growth
is simply the time spent under high tension (supported by ample evidence
as presented by Goldspink et. al.) and that other factors (those listed above
as well as hormonal factors) are secondary in nature but may increase the
adaptations seen. Several groups suggest specific set
times like 60-90 seconds (HIT advocates although the times change
>from source to source), 20-60 seconds (strength coach Charles Poliquin),
Superslow (generally 60 seconds per set in 4 slow 15 second reps) which lends
at least anecdotal evidence that some minimum time under high tension
may be a pre-requisite to simulate size and strength increases. I don't
think we can say with complete accuracy what that time is for
optimal strength or size gains but let's take for granted now that some
minimal time is necessary. Or, put a better way, slamming out 8 reps in
8 seconds with your 8RM will in all likelihood not achieve the same
level (or type) of adaptation as doing 8 reps in 48 seconds with your 8RM.
Although the rep count is the same, the total time under tension (and
presumably other factors like ATP depletion et. al.) will not be the same.
Ok, so still why failure? Assuming that stopping an 8RM set at 7
reps will achieve most of the time under tension that doing the final
rep will, why push to 8 reps? I mean, that 8th rep hurts like hell and
in the case of movements like squats and deadlifts, it may cause injury
due to form breakdown so why not stop just short of that point if we
can get similar results from it? Let me digress before I answer that
question.
Is there any evidence to the contrary in terms of the need for failure
to spur muscle growth in either the scientific or anecdotal world?
Yes, there is. We have at least one excellent example of how growth can
occur without going to failure (or even including an eccentric motion
in your lift). And that is the Olympic lifters. While many individuals
will bitch and moan about how useless the Olympic lifts are and how
dangerous they are, you cannot deny that they are some
massively muscled individuals. Having seen Wes Barnett (one of
the current US Heavyweight lifters), I can vouch for his extreme
muscularity. Not that he's as big as even the smallest pro bodybuilder
but he's built considerable muscle with the Olympic lifts. Now, Olympic
lifters can't go to failure in their lifts as it will disrupt their technique.
Also, the primary Olympic lifts (clean and jerk, snatch, etc) do not contain
an eccentric movement. And, even on movements like squats and such, most
Olympic lifters move rather quickly so there is no accentuated negative
movement in their training. Now, I don't want to give everyone the
impression that Olympic lifting is the most effective, most efficient, or
safest way to get bigger muscles since I don't think it is. But, the fact that
these individuals (who again lift very quickly, don't go to failure since
it's not feasible with the types of lifting they are doing, and don't
perform slow eccentric movements) show muscular hypertrophy throws
a bit of a wrench in the simple theory of "You must go to the point of
muscular failure in X seconds with a slow eccentric to achieve growth."
To achieve optimal growth? Well, that's a different question entirely.
Additionally, if you look at tradesmen who perform heavy manual labor,
you often see large scale muscular hypertrophy caused by much lower than
maximal work. However, their work requires large amounts of submaximal
work (time under tension) which also seems to stimulate growth.
So, we have at least two data points that show growth to occur without
muscular failure occurring. And, any theory which can't adequately
explain all data points needs to be revised. So, I'm revising it here.
Now, there is one more interesting observation that can be made from
Olympic lifters which is their generally large total training volumes
(at least when compared to systems like HG and HIT and such).
Since they rarely perform more than 3-5 reps per set and the reps are
very short (less than 1 second generally), they tend to perform lots
and lots of sets. We've all heard of the Bulgarian's training 3-6 times per
day but each session was very short, these individuals were genetically
superior, and they were most likely taking steroids so they are not
the best example. But, at the Olympic training center, the Junior
Olympic team lifters frequently train twice daily. So, although each
set is minimal in length and there is no accentuated eccentric, it may
be possible that these lifters make up for it with a large total time
that their muscles are under tension. In any event, it does make quite
a big hole in the theory that failure is the primary stimulus for growth
since it's obviously not. The story, as they say, thickens.
Now, I hate to bore you with this but Dave told me I better back up the
above argument with some numbers rather than just give a hand-waving "OL's
may perform similar amounts of total work" argument. So here goes but
we have to make some major simplifying assumptions or the math will
be impossible. Let's compare 'Typical HG Training' over the course of
a year to a 'Typical OL Training' in terms of total time under tension.
Let's assume a fairly advanced HG routine made up of squats, a pull
and a push (ignoring abs and calves in terms of total training volume).
Let me make a few simplyfying assumptions here:
1. All exercises are worked for 2 sets of 8. Yes, I know it's not the optimal
range for legs and many won't do two work sets all cycle but let me go with
it to simplify the calculations.
2. The individual trains twice per week all year round. Which is not going to
happen with movements like squats if you're training hard as we all know.
3. The individual's rep speed is a constant 5 seconds total for
concentric and eccentric (since I have never seen anyone really lift with
a 2 up, 4 down as suggested by HIT. I lift slowly but I can't even do 2/4).
4. We ignore warmup sets below 70% in terms of total volume (i.e. most
of them).
5. All sets are to failure. Again, this discounts the runup in most HG
cycles but I don't want to deal with the math.
So, You've got 3 exercises/workout *16 total reps/exercise which is 48 reps
240 seconds/workout. In 52 weeks, at two workouts/week, we have 104
workouts. So, total time under tension for this HG workout is
104 workouts * 240 sec/workout = 24,960 seconds per year that the
muscles are kept under high tension (above 80% of max) which may stimulate
growth.
Ok, onto the OL's. A couple of simplifying assumptions (which are most likely
incorrect). *BTW, the 10,000 rep number came from a friend of Dave's who
says he uses that value with his high school athletes. I have no idea
what kind of total volume Elite OL's actually use. The 10,000 value
also does not include warmups below 70% of 1RM.*
1. Rep speed is 1 second for the Olympic lifts themselves and related
movements (C&J, snatch, hang clean, power clean, jerk, etc.)
2. Rep speed is 2 seconds per rep for accessory stuff like squats, front
squats, SLDL, overhead press, etc.
3. Total training volume is divided 50/50 between primary and accessory
lifts.
So, 10,000 reps of which 5,000 are primary at 1 sec/rep = 5,000 seconds.
5,000 reps of accessory reps at 2 sec/rep = 10,000 sec. Even still, this only
total 15,000 total seconds of time under tension and even that's not accurate
as all the time during the primary lifts is not spent with the muscles under
tension due to momentum. But, I don't want to dig out my calculus book to
figure this out with total accuracy.
So, for a HG workout, we have 24,960 total seconds of work/year and for
OL's we have 15,000 total seconds of work/year. Are these values close enough
to give similar results? I would posit that the HG workout will give greater
mass gains in the short run due to more time under tension. But, 15,000 secs
is a lot of work no matter how you cut it and could explain why OL's, despite
breaking all the other sacred rules of gaining muscle do so: their total time
is fairly significant. Also, in all likelihood, the value for the HG trainee
is overestimated (since it would be rare for a trainee to do 2 work sets
every week of every cycle for a year) and the value for the OL is
underestimated (if we assume that elite OL's, who probably aren't
indicative of the average lifter anyway, would do more than 10,000
total reps per year). So, the numbers may be closer than they seem.
Ok, back to the original gist of this article.
I'm going to take the stance here that the primary stimulus for
growth is the time under tension that a muscle undergoes (or
total metabolic work performed or whatever. They are ultimately
identical in concept but differ semantically) as I think it's
best supported by the data. Hopefully I've made the point that failure
is not the critical component to growth although it may be a component
with the example of the Olympic lifters. So, why failure?
Two reasons I think.
#1: One of the big criticisms of periodization schemes is the rather large
time spent working submaximally. I happen to agree with this criticism.
Strictly periodized training programs (by that, I mean programs that
lay out the weight, sets and reps an athlete is to do in advance) leave out
one critical component which is daily variation. That is, let's say I've
measured my 10RM in the squat some time ago and, based on that, I'm
scheduled to do some percentage above or below it for a certain
number of reps (based on the relationship between percentage of max
and the number of reps one should be able to do). Well, what if I'm
feeling really good one day and can get 12 reps with a weight I could
previously only do 10? Or I'm feeling really bad and can only get 8
reps? I'm screwed is what. I'll either be working far below my maximal
potential or forcing myself to work outside my current limits which
could cause overtraining or, worse, injury. And, as much as I gripe
about HIT, I think that the double progressive system has a lot going for
it in that it avoids this problem entirely. If instead of saying I'm to do
10 reps and stop no matter what I set a range of 8-12 reps (or 4-8 or
whatever rep range I'm in at the time), I can simply accomplish whatever
I'm maximally capable of at the time ensuring I'm working at that intensity
range (if desired) regardless of daily variations.
This is how I periodize my programs by the way. HIT and periodization
are not mutually exclusive. I might have clients of mine do the following:
12-15 reps double progressive to failure for 4 weeks or more
8-12 reps double progressive to failure for 4 weeks or more
4-8 reps double progressive to failure for 4 weeks or more
rest and repeat.
Low volume periodized HIT. And they said it couldn't be done.
So, one good reason to work to at least concentric failure is to ensure
that you are working at maximum capacity instead of at some pre-
determined level which may or may not reflect daily variations.
#2: Going to failure maximizes time under tension/total metabolic
work which I argue is the primary stimulus for growth. When you
consider that failure may occur at any one of 7 sites along the
path from brain to muscle, I find it awfully naive to say that
failure (whose cause we can't even identify and which may be
different for different set times) is the primary stimulus for
growth. Obviously, going to failure in 2 reps (about 10 seconds at 5sec/rep)
will most likely have a different cause than going to failure in
15 reps (75 seconds assuming 5sec/rep). But, let's say we're
working towards size gains and let's assume for now that 8-12
reps (40-100 seconds or so per set) is the optimal range (for
the record, I don't think it is but that's another dicussion for another
day). Going to failure within that range (irrespective of how we feel
that day of training) will maximize the time spent under tension.
It's great for me to say in theory that stopping a 10RM set at 9
reps will stimulate growth. I think it would. But, that's only useful
if you know your 10RM weight on any given day. Since we can't know
without testing it every single day to take into account variations
in physical ability (and which would negate the whole point anyway since
you've already done a set to failure) all we can do to maximize
time under tension (also assuming here also that maximum time under
tension = optimal time under tension) is take a given set to failure during
any given training session.
(Oh, before I forget, some individuals who are in very good touch with their
muscles are able to pretty much know when they are getting close to failure.
Considering that certain movements (deadlifts come jumping to mind) cannot
be trained to complete failure safely, for those movements stopping
the set just short of failure (i.e. if you 'know' that you've got only 2 more
reps
in you you just do 1 more) is probably not a bad idea and will still net
you some growth. You might make up for the lack of failure by performing
a second set (to increase total time under tension) or not, it just depends
on the person, their genetics, etc.) or not.
And, that, my friends, hopefully answers the question of "Why failure?"
To be honest, I remain unconvinced that going to momentary muscular
failure is the only way to get growth as we have examples of individuals
who have rather large muscles without every going to failure. Might it
be the most efficient way to get growth? That's a horse of a different
color as the saying goes and not one I'm ready to tackle right now. But,
it's certainly not the only way.
Lyle McDonald, HB (which stands for Human Being which I am, you and
everyone else are. So forget about putting all those letters after your
name as they don't really impress anyone but you and your mom anyway.)
P.S. Please send any comments on this piece via email a I don't log on here
often. Thanx.
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Last edited by Darkhorse; 06-08-2006 at 12:54 PM.
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