To sum up what I'm going to write up in detail (I lied, I got started and went ahead and wrote it here), optimal in any sense is a matter of competing rate processes. Basically a calculus type of program where the best you can do is optimimze any one part of the system. Sure, you can always maximize some other part of the system, but it's usually at the cost of limiting some other.
For example, you could train at a higher intensity per workout (close to max), but this will limit your frequency because of both neural fatigue and increaed injury potential. Optimizing the systems means finding a COMPROMISE between all the variables, the combination of intnsity, frequency, volume, progression that optimizes what you're trying to do.
It's like the old calculus problem of what's the largest area you can enclose with a fixed amount of fence. You can maximize the long axis but it will imit the width axis, or vice versa. But neither give the maximum (optimum) area. Some compromise in long and width axis gives the optimal.
In HST, the goal is to optimize (quite generally):
c. psychological requirements
For hypertrophy. That will lead to some compromises in the system in order to maximize the system as a whole. Becaues there are ways that you might maximize 'a' but end up shorting 'b' or 'c' (tangent: my current scheme for dealing with stubborn bodyfat is in that boat, what I think is phsyiologiclaly optimal is not practical, hence it is not yet optimized ; I will end up having to forego some of the physiological optimality to ensure practical utility).
So what are the physiologicla requirements for growth (category a)? I'm going to ignore the butt simple stuff along the lines of "Pick exercises that hit the target muscles" that sort of rot. That's all pretty obvious.
If we simplified the physiologicla requirements down to one requirement it would be:
1. Stimulate protein synthesis such taht net protein accretion ocurs.
An additional physiological factor is:
1. Don't get injured
That should be obvious: gaining muscle means stimulating the mucle to synthesize more protein than you're losing over time.
So what does stimulating protein synthesis require.
1. Tension overload: this should be obvious. So why is it important. As it turns out, tension turns on a different set of genes than fatigue. The genes turns on by tension overload 'tells' the nucleus to churn out an mRNA strand that increaes the muscle's protein content. Even that has further requirements. mRNA only codes protein because of the action of ribosomes (cellular machines that turn mRNA directions into proteins).
I adressed this in detail in a thread with Alan McClure. The key components are this:
a. Exercise increases ribosome activity. After any single exercise bout, the ribosomes in the trained muscle will increase their activity. This increase is short term. Based on the data by McDougall (looking at protein synthesis via tracer research), maybe 36 hours or so. So at 36 hours, ribosome activity in that muscle is back to normal.
b. Exercise elevates mRNA levels coding for wahtever protein the muscle wants to make. As above, this is short term. Any physiology book will show that as soon as mRNA levels are elevated, the cell will start degrading them. So increases in mRNA are also transient.
c. The cell needs adequate energy (the cell 'knows' how much energy it has by a variety of means including the ATP/ADP ratio and others). This does tie in with the volume. Something to note is that the body is NOT good at doing two things at once generally. Losing fat/gaining muscle is one ; developing strength and endurance simultaneously is another. Here's one you never hear about, storing glycogen and building muscle don't generally occur at the same time. Simply, the body can do one or the other but not both (but some people can do both well and steroids increase the ability to do both which is why steroids 'let' you get away with higher volumes). So what does this have to do with the price of rice in china? In high volume training, you depelte a lot of muscle glycogen. So when you refeed carbs, they go to repleting muscle glycogen first, protein synthesis second.
I suspect that the reason that many 'hardgainers' do well on lower volumes has to do with this. With low volume, they can stimulate increaess in protein synthesis but do it WITHOUT depleting glycogen so much that incoming calories go towards glyocgen synthesis. This is probably a reason taht PL training (low reps don't deplete as much glycogen since you rely on the ATP/CP energy pathway) works so well for many as well.
Folks who can store glycogen AND syntheesize protein well (becaues of genetics or drugs) do fine on higher volumes (Since Raj likes trotting out what 'others' say I"ll play the same game and mention that Poliquin says that explicitly in The POliquin Principles, noting that certain types of training work better for individuals who are better at storing nutrients in their muscles). They are usually the exception in the weight training world as far as I'm concerned.
A couple of other issues, the inclusion of an eccentric (controlled) component. Studies show that eccentrics:
a. cause muscle damage which
1. stimultes local mechanogrowth factor release, involved in both growth and satellite cell proliferation
2. upregulates both androgen and IGF_1 receptor number in the trained muscle
I'll adress the question of "Why not just do negatives?" below.
Ok, so the above gives us a general schema for training for hypertrophy. We are trying to optimize the following: tension overload (progressive at that) along with elevating (ANd keeping elevated) both ribosome and mRNA levels in target muscles. by combining tension overload (concentric) with an eccentric component, we also generate the damage which stimulates local MGF
release (and satellite cell activation) along with increases in androgen/IGF_1 receptor number. We want to do this without depleting glycogen so much taht incoming carbs (which determine the cells' energy status and thus ribosomal activity) go to glycogen storage instead.
Given the short time courses of both mRNA and ribosome activity, this means training a given muscle frequently to keep levels elevated constantly (and remember taht that IS the goal of hypertrophy trianing, keep protine synthesis elevated as much as possible). ONce every 36 hours might be more optimal, but it's not practical for most people because it requires training at different times of the day. Training every 48 hours is a compromise based on practical considerations. Training lower volume every day is another compromise. Bryan has offered BOTH as possible solutions.
So I've just explained the PRINCIPLES behind low volume higher frequency training. It's an attempt to optimize teh above variables: progressive tension overload AND increased mRNA/ribosome levels/activity AND allowing incoming calories to go towards protein synthesis.
Now, some other considerations. What about failure, for example?
Bryan is adamant about avoiding failure (except for at the terminal workout of any given rep range). Why? Two words: neural fatigue.
Training to mucsular failure generates neural fatigue far out of proportion to the muscular stimulus. Empirically, guys going to failure and beyond need 7-10 days to regain strength production (which they are incorrectly using as a proxy for muscular recovery). Have them stop one rep short of failure (a minor decrease in metabolic work) and they recover more than twice as quickly. early stystems (i.e. Starr's heavy/light/medium) recognized this. The goal of the light workout was to give teh muscle 'some' training while allowing overall recovery to continue. Bryan approahces it by increasing tension linearly for shorter periods. So intead of H/L/M, you get lightest/lighter/medium/mediumer/heavy/heavier/. Then backcycle.
Scientifically, this has been demonstrated as well. After a neurally/muscularly damaging stimulus, strenght is lost for the first 2 days but it is NOT due to the muscular damage. Rather, it is due to impaired excitation/contraction (EC) coupling which refers to everything that goes on in between the motor neuron (releasing acetyl choline) and the actual muscular contraction. The short-term strength decrease from this type of training is neural NOT muscular. So generating it and then waiting for strenght to recover (HIT fallacy #375) is limiting the stimulus to the muscle as the expense of the nervous system. W hich is fine if your goal is nervous system training, but the goal of hypertrophy/HST is muscular.
So consider a situation where you trained to failure during your work sets. This causes too much neural fatigue to let you train again in a couple of days (or if you do, you have to use lighter loads which doesn't fulfill the requirements of progressive tension overload which means you are already undermining your goals). It's also possible that higher volumes might cause too much damage along these lines which would ALSO impair your ability to return to the gym and repeat the workout. Which compromises the goal of increasing (and keeping increaed) mRNA/ribosome levels. Basically you need enough volume to turn on the adaptations WITHOUT generating so much neural fatigue or muscular damage taht you impair your ability to meet the freuqency requirements. I know that's not the PROOF that Raj wants but that's the PHYSIOLOGICAL PRINCIPLE behind the set count.
To avoid failure and the accompanying neural fatigue, Bryan suggests starting submaximally, which *allows* you to add weight at each workout. This lets you generate the muscualr cahgnes at each workout with progressive tension overaload (mRNA, ribosomes, etc) WITHOUT generating the neural fatigue that would compromise said frequency. Again, it's about optimizing a number of different variables at the same time. You may not maximize any one variable, but you max maximize the system as a whole.
Ok, now you do hit failure at the end of every 2 week cycle. Which will generate some neural fatigue and cause problems of EC coupling. But its followed by a built in backcycle as you start the next rep range at a submaximal level. As well, it's fundamentally impossible to avoid ALL neural fatigue and it will accumulate over the length of the cycle. Which the week off at the end goes a long way towards helping with.
That same backcycle also ties into injuries. Going at max for long periods is a great way to get a joint injury because your joints and connective tissue take longer to recovery than your muscles. Every 2 weeks you get a backcycle built into the system. And every 8 weeks you get a full week off (which has other implications).
Ok, so the next question: why 2 week cycles? Why not longer or shorter? Is there some magic in 2 weeks? Frankly, no. Bryan picked it as a compromise. He and I have discussed it and longer cycles would work just as well (using smaller percentage increases, that sort of thing). So why 2 weeks? Ties into psychological issues. Bodybuilders are notorious for not liking to work submaximally (look at how many idjits on the HST board comment that the yare going to follow the program but still want to work to fialure).
He had to find a balance betewen what *might* be physiologically optimal while still fulfilling the psychological needs (and anyone who thinks that psychological requiremenst are equally critical in program or diet design is a true theorist who doesn't know anything about human beings or how to train them) of bodybuilders to work to failure. They don't like to work at low effort levels which a 4 or more week cycle would require. So he settled on 2 weeks. They have to start less submaximally, can use larger weight increases (fulfilling other psychological needs) and hit a RM every 2 weeks. A compromise to try and optimize two different variables.
Ok, so that explains the frequency, intensity, progression and non failure part of it. As well as the 2 week cycle (which is arbitrary, but is a compromise between physiological and psychological needs).
Ok, what about the rep progresion. Why 15, 12, 8, 5, negatives? 'Why not' is the answer. Seriously, anyone who thinks that there is a magic to rep counts is on drugs. Raj will clamor for proof but I can find guys who get big on any rep count you can pick. Everything from singles up to 20 rep squats and everything in the middle. You could use 14,11,9 and 6 for all it would matter in the big scheme. 15, 12, 8 and 5 are commonly used rep ranges in training, hence psychologically easier for most to accept. Same reason so few coaches use sets of 13 for anything. It's tradition more than anything else.
But even that's not entirely correct. And it goes back to the injury issue. As you use continually increasing tension loads (to fulfill the physiological requirements elucidated above), you start to get cumulative damage to connective tissue and such (which heals more slowly than other tissues). Trying to keep adding weight forever eventually leads to injuries. So you counter "Why not cycle weights differently?" Becasue that doesn't meet the requirements of progressive tension overload and the other goals of the system.
By the time you get to the negatives (adressed next), you're pushing that envelope of injury (although this is highly individual). First and foremost, the week off will give you some time to heal (on top of another critical component). As well, starting with the higher reps gives you more time to heal, jacks up blood flow to the joints, and has hormonal effects that may help with connective tissue healing and injury.
Personally, I do NOT consider 15 reps an OPTIMAL range for hypertrophy (for a bunch of complicated neurological reasons I've elucidated before and this is long enough already). It's a compromise that Bryan decided on to give connective tissue microtrauma time to heal. And note that Bryan has said that you only NEED to do the 15's if you feel strain (joint) injury coiming on. it's not a REQUIRED part of the program (listening Raj?), but suggested IF you need it. Otherwise start at 12's which is more consistent with hypertrophy (higher tension) anyhow. Again, starting back at 15's is a compromise between physiological and practical (and injury) requirements. But that's part of the entire system: trying to optimize all the variables that go into things at the same time.
Ok, negatives and the week off since they are related. If there' a reason folks stop growing (well, there are lots of reasons) here's the one nobody every mentions. As you train, your body increases the amount of connective tissue within your muscular structures. This is geared towards one thing: decreasing muscle damage from training.
But what did we establish was a REQUIREMENT for growth: muscular damage. As you train consistently, it becomes harder and harder to generate that damage. ONe way to keep damage omcing is to keep increasing the weight, which is already built into HST (you progress from lighter to heavier over the cycel). Another is with negatives. That's the reason for their (suggested but NOT required) inclusion. An atteempt to generate a little last bit of muscualr damage at the end of the cycle as your body is adapting.
Of course, that has to be considered within the context of the overall system. If you're already beaten up, or can't do negatives safely, adding them (again, suggested but NOT required, Raj) is a poor choice. If you're fine joint wise And can do them safely, they may add to the program. If it injures you, it's crossed the line of optimizing one of the variables (don't get injured) and isn't part of it.
Of course, as anybody knows, doing negatives for long periods generates so much muscular damage (and neural fatigue for a bunch more complicated neurological reasons that I"m not boring anybody with since I'm not up to date on them anyhow) that you overtrain. So Bryan suggests (but does NOT require, Raj) them at the end of the cycle.
Righ before the week off. Which has several goals. The first is general recover (neural, muscular) after the entier cycle. The second goal is as important: detraining lets the increaesd connective tissue go away so that you can get more easy damage when you start the next cycle.
Taht is, at the end of 8 weeks of continuous training (or wahtever the exact numbers are), damage is too hard to generate because of increaesd connective tissue (and the practiacl realities that you can only add weight for SO long before you get hurt). A week off (strategic deconditioning) lets some of that CT adaptation dissipate so taht damage (and hence growth) is easier the next cycle.
You also have to hope that connective tissue adaptations go away faster (or to a greater degree) than the size increases which is supported by data (the early de-adaptation to training is neural first). AS well, if you did the eccentrics, you should have a delayed training effect that keeps growth going as the connective tissue is going away. Well, hopefully.
The question: is 1 week enough? Some of the data says no, that some of the connective tissue adaptations are still present weeks or months after detraining. It might be physiologically optimal to take 3 months off every cycle but taht crosses practical optimality, not to mention psychological issues.
Even if it takes 6 months for CT adaptations to go away, that's not practical for training (train 8 weeks, take 3 months off) because you'd lose any muscle gained. Nor would it fulfill psychological requirements because most folks hate being out of the gym even if its better for them in the long run (Bryan and I have talked about other ways around this, like very light training because obsessed bodybuilers hate taking time off). Once again, its a compromise between trying to maximize the physiological response while taking into account practical and psychological realities.
And those are the main PRINCIPLES behind HST. Read taht sentence again, Raj. The PRINCIPLES. That's what this thread is mainly to criticize.
Summing them up more or less:
Non failure and lowish volume to avoid neural recovery which impairs training frequency which is necessary to elevate (and keep elevated) mRNA/ribosome levels, an eccentric component to generate MGF
release and changes in receptor number, etc, etc. The low volume also avoids glycogen depletion which requires that the muscle first replete muscle glycogen before it can synthesize new muscle. &c &c. It was a multiple degree of freedom system that Bryan tried to optimize, maximizing all of the variables without significantly shorting one.
Because you can easily come up with systems that will increase one variable but at the major expense of another. WAnt to do higher volume or go to failure? Fine, but the fatigue will decrease frequency of training which limits mRNA/ribosome activity. Want to do negatives all the time for maximal damage? Fine, but you're going to get injured, or get so neurally fatigued that you lose far more than you gain. Etc.
Bryan had to look at ALL of those competing variables to come up with the PRINCIPLES behind the system. The exact scheme that Raj is criticizing off of Thinkmuscle is ONE interpretation of those principles which is mainly for folks who need hand holding. Apparently he still doesn't understand the difference.
The 2 week rep cycles are fairly arbitrary, Bryan would agree. Someone who can psychologiclaly handle longer periods working submaximally (like me) could use longer cycles. 2 weeks is a nice compromise between getting folks to work submaximally and not having them get antsy (psychological) about working submaximally.
8 weeks is convenient in that it lets you get 4 progressive rep cycles (including the 15 rep cycle aimed mainly at injury control) of 2 weeks apiece (NB: in Supertraining, Siff/Verkoshansky note that 16-18 week cycles with 8 week mini cycles was 'found' by Russian coaches to be aabout optimal before al onger time off was necessary). Then a week of negs (suggsested but NOT required) for a last littel bit of damage before the week off.
You could set up a 16 week cycle that adhered to the primary HST PRINCIPLES quite easily. I gave an example for Hella1 for dieting. An INTERPRETATION of the HST PRINCIPLES for a specific situation.
But the principles stay the same. And I contend that they are as optimized as they can be (optimized within the context of a nubmer of competint goals) towards hypertrophy. Individual interpretations get into other practical and/or psychological issues.
But the physiological optimality is all based on fundamental biological principles of the human body.
Whew. I'd say that was better than geting laid but I don't have any frame of comparison. Hopefully it will answer any questions anybody still has, and explain to Raj what's being discussed here. He's too busy focusing on trivialities (specific interpretations) and ignoring the principles of the system.