The 4+2 method is a favorite of mine. And rightly so, since it is a very effective tool for functional hypertrophy. Click here to learn how to apply it to your back workouts.
But… A less known benefit from this method is that it allows to assess the strength deficit.
And, this specific piece of information will ultimately tell you whether to gear your training towards hypertrophy or strength.
What Is The Strength Deficit? And How To Calculate It Anyway?
The strength deficit can be easily evaluated by comparing eccentric and concentric strength. Why so?
Well, according to the ascending recruitment principle also knows as the size principle, slow twitch fibers are recruited first during the exercise and faster twitch fibers last. YET when it comes to eccentrics movements the faster twitch fibers are called into action preferentially and almost exclusively. Thus violating the principle.
So during the eccentric portion of any exercise the fast twitch fibers aka the survival fibers are preferentially recruited. You can tell where the term “survival fibers” comes from upon witnessing eccentrics taken to failure. Namely: a colorful enactment of an epileptic seizure. Anyway, this peculiar mode of recruitment entails less total fibers recruitment. Still, those chosen few are the stronger ones. And this is why eccentric strength provides an accurate estimation of absolute strength.
As a matter of fact, absolute strength would be a 100% recruitment of all fibers. In other words a tetanic contraction of the muscle when all fibers fire simultaneously. At the opposite, lesser force input translates into an asynchronous contraction. This kind of asynchronous contraction allows to perform endurance tasks.
Tetanic contractions can’t be achieved under normal circumstances. Elite powerlifters being the exception to the rule as they are able to near 90% recruitment of motor units after (MANY) years of training.
Calculation Using The 4+2 Method
The 4+2 method is pretty simple.
Select a compound exercise (bench press, squat, chin-up, deadlift…)
Warm up to your 4RM. Use a 40X0 tempo.
Upon completion of the fourth grueling rep, have two partners add a weight on the bar that allows you to perform two strict eight second eccentrics.
A conservative approach is to begin with a 10-15% increment in load. Adjust upwards if possible.
The higher number is your max eccentric strength. And the strength deficit is the % difference between your max eccentric and your 4 RM.
Say, your 4RM is 200lbs on the bench press. And you did 2 eccentrics at 250 lbs.
Your strength deficit is: (250/200) – 1 = 25%
How to Put the Data to Use?
For an athlete, depending on how close is the next competition a 1-40% variance is where you want to be.
For a bodybuilder, a 25-40% variance is acceptable.
Less than 25% reveals a poor eccentric strength. The good news is: it also means that you are very efficient at recruiting your fast twitch fibers on the concentric portion of the lift. Actually it means you have maxed out your strength potential for your actual muscle cross section. Consequently you will hugely benefit from a 12 cycle focusing on eccentric work as this will allow you to gain size.