The Strength Deficit Formula Will Help you Decide Between

Practical Application of the Strength Deficit

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Do Your Suffer from a Strength Deficit?

Specific performance demand specific types of strength. They are a necessity to grow. A strength deficit can hamper your gains in muscle mass or strength. What is a strength deficit? It refers to the ratio between concentric and eccentric strength.

Essentially, an eccentric contraction refers to an action where the muscle cells contracts while elongating. Think absorbing forces when you land after jumping or lowering the bar when you initiate a squat or a bench press. Eccentric contractions are an important part of life, but even more so for athletic performance. Bodybuilders should also mind the strength deficit to help get stronger, faster, and bust through plateaus in mass gains.

By making you focus on one type of contraction over the other to balance this ratio, you can cut the guess work and get straight to what you need.

So, decide what to focus on. Save time. Make your efforts count. Use the strength deficit formula.

What is it?

Everybody knows that you can lower much more weight than you can lift. But how much more exactly? The difference between how much weight you can lower under control (key words: under control) and how much you can lift give you a ratio. This is the strength deficit.

Concentric strength is the amount of force your muscles are able to produce while shortening the muscle (lifting).

Eccentric strength is the amount of force your muscles are able to produce while lengthening the muscle (lowering).

Let’s say you can bench press 250 lbs for 1RM, but you can lower 275 lbs under control, at a 4010 tempo. To calculate the ratio, you use the following formula: (Max Eccentric/Max Concentric -1) x 100 = Ratio in %.

In our example, that would be: (275/250 -1) x 100 = 10%.

Another, more scientific way to put it, is that the strength deficit is the % difference between absolute strength and maximal strength. Simply put, it is the % of strength that you are NOT able to express in any given movement. This definition explains why the ratio can change during a training macro-cycle, as an athlete will peak, and thus be able to utilize a larger portion of his or her absolute strength for the most important competition of the year. Think World Cup/Championship or Olympic Games.

A few more definitions:

Maximum strength is the amount of force you can produce voluntarily. It is your 1RM in exercises such as the squat, deadlift etc.

Absolute strength would be the amount of force produced with total recruitment of all fibers, i.e a tetanic contraction when all fibers fire simultaneously. The opposite is asynchronous contraction. Asynchronous contractions allow endurance performance.

Tetanic contractions cannot be achieved under normal circumstances. Elite powerlifters are able to recruit about 70% of motor units. But this is only possible after many years of specialized strength training. 100% recruitment occurs in rare life-or-death situations.

Putting it all together

The ascending recruitment principle also known as the size principle, explains that slow twitch fibers are recruited first during concentric contractions. The fast twitch fibers are recruited last. Conversely, during eccentric contractions, the fast twitch fibers are recruited first and almost exclusively. Hence, while eccentric contractions recruit less fibers in total it recruits preferentially the fast twitch fibers and this is why eccentric strength provides an accurate estimation of absolute strength.

How to calculate your strength deficit in the gym?

The first question to answer is: should you test for this? The strength deficit is a great tool. It is most beneficial for advanced athletes however. This means that beginner and intermediate athletes should put their training focus elsewhere. A minimum of 4-5 years of serious training with various types of contraction (concentric, isometric and eccentric) is a minimum prerequisite before thinking about finding out what your strength deficit is. Read our disclaimer below

That being said, it is also a great tool for peaking phases and busting through plateaus if you are a bodybuilder/physique athlete that reacts well to strength gains in your quest for more muscle mass.

The methodology suggested below is but one of the many ways to test for your strength deficit. It requires a competent coach to oversee the training and at least 2 spotters. They will make sure that this test is done as safely as possible. Be advised that there is a risk of injury, as with all testing that stresses the body.


Set 1 – 60% of 1RM x 3 – 4010; Rest 60 seconds

Set 2 – 70% of 1RM x 2 – 4010; Rest 90 seconds

Set 3 – 75% of 1RM x 1 – 4010; Rest 120 seconds

Set 4 – 80% of 1RM x 1 – 4010; Rest 180 seconds

Set 5 – 85% of 1RM x 1 – 4010; Rest 240 seconds


Set 1 – 90% of 1RM x 1 – 4010; Rest 240 seconds

Set 2 – 110% of 1RM x 1 – 4010; Rest 240 seconds
Eccentric only; have the spotters lift the bar back up

Set 3 – 95% of 1RM x 1 – 4010; Rest 240 seconds

Set 4 – 125% of 1RM x 1 – 4010; Rest 240 seconds
Eccentric only; have the spotters lift the bar back up

Set 5 – 97.5% of 1RM x 1 – 4010; Rest 240 seconds

Set 4 – 140% of 1RM x 1 – 4010; Rest 240 seconds
Eccentric only; have the spotters lift the bar back up

Sets 5 & 6 are optional and should depend on how set 4 is performed. The coach should assess the speed at which the bar is lowered and the technic. If bar speed or proper technic are not adequate, terminate the test on the 4th set. If not, go ahead and try sets 5 & 6.

How to put that knowledge in practice?

For bodybuilders

For a bodybuilder, you can allow a 25-40% bracket.

When the percentage drops below 25% it is indicative of poor eccentric strength.

Actually, it means you are good at recruiting your fast twitch fibers during the concentric portion of the lift. You have for all intents and purposes reached your strength potential for your current muscle cross section. So, you will make more progress by focusing on size.

When the strength deficit is low, for instance 25 to 40%. your best bet is to focus on strength. It would appear that you have room to improve your ability to voluntarily recruit your muscles.

For athletes

When it comes to athletic performance, generally, a 1-40% variance is seen. This depends on how close the competition is. During off-season, athletes are closest to the 40%. They want to move toward the other end of the spectrum closest to 1% when peaking, depending on the sport. This will allow them to perform optimally in competition.


Case 1: You need more size.

Considering your eccentric strength is the weakest link, it makes sense to improve your eccentric strength.

Use a 12-week cycle during which 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 a 6-8 second eccentric
  • The Pause Method – Perform a 3-4 RM and for the last rep pause three times on the way down. Each pause lasts 8 seconds. That’s, 3×8, a total of 24 seconds eccentric. While this is technically an isometric method, the overload happens during the eccentric phase, placing the stress on that type of contraction.

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.

Case 2: You need more strength.

There are many methods to improve strength

– An oldie but goodie: 5,4,3,2,1

– wave-like loading

– clusters

– or the modified Hepburn method:

This training protocol pairs antagonistic muscles.

A1 and A2 exercises focus on neurological activation. Pick basic exercises. Keep 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 weight to about 80%.

The key to progression from workout to workout is progressive overload. Each workout average tops the previous one. For instance:

Workout 1

Set 1 = 95kg

Set 7 = 100kg

Next workout

Begin at 97.5kg and use 105kg on your last set.

A typical workout would be

A1- Front squat, medium stance, 7-10 sets, 1-3 reps, 40X0 tempo, rest 2 min

A2- Lying leg curl, plantar flexed, feet out, 7-10 sets, 1-3 reps, 40X0 tempo, rest 2 min

B1- Front squat, narrow stance, heels elevated, 5 sets, 5 reps, 40X0 tempo, rest 2min

B2- Lying leg curl, plantar flexed, feet in, 5 sets, 5 reps, 40X0 tempo, rest 2min

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.

Final words

Know thyself. Kung Fu Tzu had it right a millennium ago. Although he is remembered as a philosopher, he would have made a great strength coach with this statement. Know your strength deficit ratio to optimize your progress, whether you want performance in the field or just pure muscle mass.

The Strength Community


Before beginning any exercise program or health program, please consult with your physician to make sure you are in good health. This article is not meant to replace proper medical advice by a qualified health practitioner nor the supervision or an experienced coach and the use of proper assistance and technique. No liability is assumed by Strength Community, for any of the information contained in this text or any other.

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