In the strength world, the Strength Deficit is a potent indicator of the difference between your concentric strength and your eccentric strength
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.
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 higher threshold 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 70% 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 Assess The Strength Deficit Without Spotters
Find your one 1 RM concentric using a 40X0 tempo. Then 5 days later, measure how much you can handle eccentrically in a 80X0 tempo. Make sure the concentric range is 80% of previous R.M., for safety purposes.
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. Let’s take an example, for a hammer thrower, when peaking at the Olympics, 1% is what you want, however in the general preparation you want a 40% difference
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.
Eccentric training causes more muscle damage because the load per motor unit is larger. All muscular damage calls satellite cells into action. They fuse with the damaged fibers adding their nucleus and thus potentiating further hypertrophy. In addition, eccentric based movements trigger a greater IGF1 release than their concentric counterparts.
At the other end of the spectrum, if the strength deficit is not significant, say 25 to 40%. You’d be better off focusing on a strength phase. Since you have room to improve your neurological efficiency.
Now, I Want to Train For Size, What to Do?
First you should strive to improve your eccentric strength. The best route is to allocate a good 12 week cycle to your plan and focus on eccentric strength. During this cycle you will be doing one eccentric focus workout out of two.
Two great methods to improve eccentric strength are:
- The Slow Eccentrics Method
7-8 sets of 1 rep with 8 seconds eccentric
- The Pause Method
Perform a 3-4 RM and for the last rep pause three times on the way down. Each pauses lasts 8 seconds. That’s, 3×8, a 24 seconds eccentric.
Your training partner calls the pauses at random. You should be able to stop the weight at any point across the ROM. Dorian Yates is famous for emphasizing this point: if you have picked the right weight, you can stop the weight wherever you decide.
I guarantee 10-12 days of intense soreness. Enjoy!
What If I Want to Train for Strength? How to Improve My Strength?
There are gazillion ways to do so but the Hepburn method would be a great choice.
This training protocol pairs antagonistic muscles.
A1 and A2 exercises focus on neurological activation. Pick basic exercises. Kind in mind that each rep needs to be perfect. This is not the place for forced reps. Concentric failure should occur on the last sets for A1 and A2. So pick the weight accordingly.
When selecting exercises B1 and B2 keep the same movement pattern but choose a slightly different exercise in order to tap into different motor units. Also, drop the weights by about 80%.
The key to progression from workout to workout is progressive overload. Each workout average tops the previous one. For instance:
Set 1 = 95kg
Set 7 = 100kg
Begin at 97,5kg end at 105kg
A typical workout would be:
A cycle on this program will generally last 4 to 6 weeks depending on your strength levels.
Wait at least 16 weeks before repeating it.
You are now privy to the hidden benefits of the 4+2 method. Which, a great avenue for functional strength, also proves to be a useful tool to evaluate where you stand on the strength deficit continuum. And as we have seen this piece of information will ultimately inform your choice on whether to gear your training towards hypertrophy or strength.
Coach Charles R. Poliquin