HighIntensity.net View Mike Mentzer Bodybuilding Topic

I′ve been off of the board for a few weeks and doing A LOT of thinking about intensity/ HIT theory….But you all went and had the discussion without me! 😉


Definition of intensity (Physical and mental)

*Mechanical Intensity of set = %Strength Inroad Acheived/time = work/time = power demands of set.

i.e. The higher the rate a muscle does/ has to do work the quicker it tires out. A self-evident truth as Arthur Jones would put it. So yes, a 1Rep Max IS more intense than a 10 rep set. But only mechanically.

*Perceived Intensity = Power Production/Ability to produce power.

i.e.The ability to produce power is reduced by mechanical work done (in a set). Thus a 1rep max lift feels as hard as the tenth rep of 10 reps to failure.

Though I am unsure of the exact relationship: (rate of work done = POWER output) has a direct link with the intensity equation. That is to say the more work a muscle has to do per second the quicker it tires out.

Because our negative strength is so much higher than our positive strength we can ask much more work from the muscle thus inroading it quicker. Thus if we were to strap on 300% of the weight we were using for positives and do negatives to failure we could increase the power demands on the muscle thus inroading the muscle quicker making for a more intense set. Used at the end of a straight set it would also make for a deeper inroad as negative strength reserves remain when the positive has failed.

An excess of mechanical work is the cause of overtraining – however we must necessarily do a certain degree of muscular work in order to reduce the momentary ability of a muscle to produce force. The trick is to minimize this work or at least offset the extra work done with extra recovery.


Universality of Inroading

*%Strength Inroad acheived = 1-(weight failed at/1rep max weight) x100

I truly belive that the theory of percentage inroad specific to the individual are the single most overlooked factors in HIT theory today. I have had experience of low frequency workouts with lower percentage inroad (20-15%) in which I never progressed. Now my inroad (30%) is much higher I am seeing consistent gains. I belive it makes or breaks the theory. Recently I have had success with higher faster reps AND LOWER Slower reps USING the same resistance. Only the theory of inroading covers it.

What other way is there to accuratley determine how far one has pushed ones muscles? It′s certainly not the forces we expose them to (Or the prevalent trainning method would be to do lots of singles). It′s not anerobic work either, other wise sprints would be the best way to train legs. Neither is it perceived intensity – if that were so, going to failure or trying to move an immovable object i.e pushing against a house would turn on the growth mechanism – which we know it doesn′t. Inroad is KEY.

There is a lot of talk about High TUL/TUT or reps for ectomorphs and Low reps/ Low TUL/TUT for mesomorphs due to fiber distribution. This is a side issue. What really needs to be talked about is percentage inroad. Though the underlying fiber type distribution may be the biological reasoning for this difference – peoples resistance to adaption in the face of resistance trainning can be overcome with the abstract concept of percentage inroading. Simply put – a natural mesomorph needs a less extreme stimulus for their body to adapt. They CAN pick up a (80% of max) weight on which they go 3-4 reps shy of failure and STILL GROW. This because they have reduced their momentary abilty by at least 10%. That is why they were so big in the first place before they ever entered the gym – they had been stimulated by their everyday lifestyle! Most of us need approximatley 80% inroading. But some need more. Those of us who are naturally very ectomorphic require a deeper strength inroad for our body to take notice. You have to work very hard to attain a 30% strength reduction – it you might only get pushed that hard once a year if you didnt train in the gym. In short, Ectomorphs/Slow twitch people tend to exhibit a resistance to trainning whilst Mesomorphs/Slow twitch people are relativley more sensitive.

Another thing to bear in mind is that those with a higher inroading requirement have more slow twitch fibres so will probably never be mass-monsters.

TUT is only important because it takes TIME to do the work to make an inroad into ones strength. Thus there is a positive correlation between the strength inroad made in a set and how long that takes to accomplish. You can accomplish this inroad in one of two ways with a single resistance = High Reps X Fast cadence OR LOWER REPS X Slower cadence. The later is preferable as saftey and full range strength is promoted.

Improvement in number of repetions/TUT shows us that the body has ′failed′ at a percentage inroad HIGHER than the previous workout.This is because the one rep max capacity has increased slightly relative to the weight being used.

This does not mean that we should all do roughly 2 minute sets and create a strength inroad of maybe 40%. There is no point. Most people will make progress on a 20% inroad – any more than what is needed is counter productive in terms of recovery ability as you need to do extra WORK to acheive that inroad.It just so happens that i need 30+% 🙂

This also tells us why negatives, cheat reps, Brakedowns etc work. Because they are ways lower the momentary ability of the muscle further still once strict failure has been reached. However this model doesn′t account for why rest-pause reps work.As rest pause reps are essentially a repetion of the final failed rep.

The above three equations, the theory of work being the determinant of overtraining and the importance of inroad – go a long way to explain a lot of things.

**1) Why HIT is the most efficient way of stimulating and positive response BUT why volume can work.**

Trainee X has a 100kg 1rep max in the leg press.

They can do (20% inroad) 80kg x 10reps @ 4/4 (Total work 80 units)

OR (30% inroad) 70kg x 15reps @ 4/4 (Total work 1050 units)

If the trainee had an inroad requirement of 20% then they would be better off doing 80×10 as opposed to 70×15. This is because they would have done the minimum amount of work necessary to challenge the body to a sufficient degree. The 70kg set he never did would have inroaded the trainee further but would also have required more work than absolutley necessary – thus upping recovery requirements above minimum. A properly tuned single set to failure is the best way as it un-neccesary work is kept to a minimum.

Why Volume Trainning can work but is less efficient at stimulating a positive response.

Trainee X starts volume trainning and does 3sets of 8x80kg leg presses.

He does set one and does 8 reps (though he could have done 10 – he has lowered his temporary ability to 86% say…)

He rests 90secs (Regains some temporary ability upto 98% say)

He does set two and does another 8 reps (He could have done 9 – he has lowered his ability in this set to 83%)

He rests another 90 secs (Regains temporary ability upto 96% say)

Final set of 8 reps to failure (Temporary ability lowered to 80% and adaptation stimulated)

The only problem here is that the trainee has done 640×3 = 1920 units of work opposed to the 800 absolutley neccesary to reduce his momentary ability to 80%.

**2) Why sub-failure trainning works.**

Sub-failure trainning works because the inroad can be created wether we reach failure or not. By the 12-13 rep of the above 70kg hypothetical set the momentary ability of the muscle would be reduced to 80% of what it was and thus a positive adaptaion would be stimulated.

3) Why we must train less as we get stronger.

As our weights go up we have to do more work to inroad our muscles sufficiently – more work = more recovery time required.


I am very likely repeating something known to all on the board here but I haven′t seen anything written overtly about this in any detail. If you are sleeping well, eating well, trainning with single sets relativley infrequently and there is no progress still DEEPEN YOUR INROAD as much as is necessary until you see your strength increase!

That just about covers my thinking concerning intensity – which for once I belive is fairly bullet proof. The theory of inroad is less complete as it may be that volume/work loads can increase size. Either way – criticize it to peices! 🙂

I hope you find the above easy to read – i know i can waffle.

Thanks for your time!


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