Bi-Lateral Deficit Specialization For Balanced Muscle Size, Strength & Symmetry

Dennis Weis

Articles, Muscle gain, Strength and performance

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Bi-Lateral Deficit Specialization For Balanced Muscle Size, Strength & Symmetry

Bi-Lateral Deficit Specialization For Balanced Muscle Size, Strength & Symmetry

Bilateral deficits (AKA-Asymmetrical, Asymmetric, or Ipsilateral deficits) are very common-and most bodybuilders have them. A bilateral deficit is where the symmetry (and strength) of the muscles on one side of the body is better than those on the other side.

The following story illustrates the appearance of bilateral deficit symmetry. I had the opportunity of seeing Frank Zane guest pose at a bodybuilding competition a few months prior to his first of three consecutive Mr. Olympia wins.

“I snapped some photos of his posing exhibition and I was shocked when I saw a couple of photos. One of his calves looked like it measured about 12-inches in diameter while the other one looked fully developed. Now, in this case, it wasn’t that his calf was out of proportion but more of my inability to get a good camera angle.”

Another example of bilateral deficit symmetry is when measuring the biceps, forearms, thighs & calves. There can be as much as an inch difference in the measurements. Bilateral deficits are even a problem among the most seemingly symmetrical professional bodybuilders though in the story about Frank Zane this wasn’t the case.

Bilateral deficits are not exclusive to symmetry and muscle group measurements. There have been extensive studies over the years where the strength outputs of exercises done with two arms or two legs were tested against the strength outputs of doing the same exercise with just one arm or one leg, and guess what? As no big surprise a person tends to generate more strength output (i.e. lift more poundage) with their dominant limb (i.e. arm, leg) than with the non-dominant one.

For example, if your dominant limb is your right arm or leg you will be able to generate about 20% or more strength output than that of your left limb. Here’s an example: If you can do a 100-pound dumbbell press overhead for a couple of reps with your right arm then most probable you will only do 80-pounds with your left arm.

Some experts say that no extra reps or sets are needed for the weaker side with regard to improving muscle development and strength.  They argue that if a person trains both sides equally but concentrates more on the weaker side it will all balance out in due time. I believe otherwise.

There is a rather easy solution to solving a bilateral deficit in symmetry or strength output. Simple add one-limb (arm or leg) exercises to your current exercise program or better yet do a 4-6 week specialization program to derail bilateral deficits in symmetry and strength.

Virtually any exercise that can be done with both arms and legs with a barbell can be done with one arm or leg, using one-dumbbell.

And likewise, any exercise machine (Cable, Leg Extension / Leg Curl, Leg Press, Hammer Strength, Pec Deck, Smith etc.) where either of the arms or legs are used can be adapted to one arm or leg and most effectively and without having to worry about balance or stabilization issues

To give you an idea of how bilateral deficit training can be accomplished, here’s a brief peak at the One-Limb strategy Flex Wheeler, IFBB Living Legend and Hall of Fame Professional Bodybuilder, used when he was training for a pro bodybuilding show.


Hack Machine Squats (both legs)
Followed by…
Leg Extension Machine (one leg at a time)


Barbell Bent-Over Rows (both arms)
Followed by…
Seated Cable Row Machine (one arm at a time)


Lat Machine Triceps Pushdowns (V-bar, both arms)
Followed by…
Reverse-Grip Cable Pushdowns (one arm at a time)

I have seen other One-Limb strategies where some of the top pros use the Alternate-Rep Method. With a dumbbell in each hand, they would begin to do such exercises as Curls, Flies, Lateral Raises, Press’s Overhead, Bent-Over Rowing, and Triceps Kickbacks simultaneously.

As the muscles begin to fatigue they would switch to doing the reps in alternating style (left, right, left while maintaining maximum concentration etc.). This, of course, gives the non-working limb a very brief Asymmetrical-rest-pause, which results in a few more reps overall compared to having to terminate the set when doing the movement simultaneously.

One of the most important things a bodybuilder can do when training one-limb at a time is to make sure that the body is aligned in nearly the same posture as it would be when doing the movement with both limbs.

For instance, if you decide to do One-Legged Barbell Back Squats, for the left leg, in a power rack or Smith Machine, don’t trust the non-working, right leg out in front of you. This will change the adaptive response of the nervous system to the thigh muscles in a way that won’t guarantee the best improvement of a bilateral deficit.

Take the normal squat stance with both legs and then do as much of the lift in the positive (Do in under 2 seconds) and negative (Take 5-8 seconds to execute) phase of each rep as possible with your left leg. The right leg is only used to assist in stabilization & balance.

Another way to grasp this concept is to pretend that the shin bone of your right leg is broken and as a result, you can’t exert any pressure on it. Thus the quads in your right leg will not contribute or generate any type of significant strength or force output to complete the assigned reps. Here’s a 4-set combo you can gradually incorporate into your workout program for the One-Leg Barbell back squat:

Set No. 1 – Squat 2-inches above parallel

             2 – Squat to parallel

             3 – Squat 2-inches below parallel

4 – Squat 4-inches below parallel

6-10 reps

6-10 reps

6-10 reps

6-10 reps

The 4-set combo is considered to be one cycle.

Stay with the 4-set combo and assigned reps till you feel totally comfortable doing the One-Leg Barbell Back Squat.  Then gradually decrease the number of reps down to 8’s then 3’s and 2’s using as heavy poundage as possible for each unique squat position (above or below parallel etc.). Stay at a particular rep range for two to three weeks before moving down to the next rep scheme. Work up to doing two cycles of the 4-set combo.

Note: Do the 4-set combo cycle once or at the very most twice per week (on non-consecutive training days) when doing rep ranges of 6-10, 8’s and 3’s. When you get down to 2 reps or even singles do them only once every couple of weeks.

When doing an exercise for One-Limb, such as a One-Dumbbell: Curl, Lateral Raise or Press Overhead etc., also hold a dumbbell in the non-working hand (unless otherwise instructed) at the customary start position as a means of balance and bi-lateral posture.

This instruction will vary slightly in the case of a one-dumbbell flat bench press. Do not grab any part of the vertical upright support rack with the non-working hand as this is an out of normal position will change the adaptive response of the nervous system (mind to muscle link) to the chest muscles. Instead, hold a dumbbell in the non-working hand, at chest level rather than overhead.

Another bilateral deficit strategy is to do one-limb movements in Negative Only style. For example on machines such as the Hack Squat, Leg Extension / Leg Curl, Leg Press using both limbs (legs) when doing the positive phase of each rep but then lower through the negative using only one limb (leg).  Use about 30% less poundage than normal. Each negative only rep should take between 5-8 seconds.

Here is another strategy as it applies to perform the (one-limb only) NEGATIVE LEG PRESS. Perform one hard work set of 20 full exercise range of motion (eccentric/concentric) reps, with the right leg. Upon completion of the 20th rep, load an additional 25-30% poundage to the apparatus.

With the weighted foot platform at the beginning range leg length position, release the safety latches, lower the poundage very slowly (8-10 seconds per rep) down to the rubber stops at the bottom of the leg press unit.

A training partner or spotter then helps lift the poundage back to the beginning range leg length position. Immediately begin a second (one-limb only-right) negative rep as described. The set terminates when a 3-4 second negative cannot be maintained.

Strive for 6-8 negative only reps, while breathing rhythmically throughout the set. Next train the left leg in the manner previously described.

Even negative only pull-ups can be done by pulling up through the positive phase with both limbs (arms) and lowering with one limb (arm). Use the hand of the non-working arm to hold onto the wrist of the working arm, as a control mechanism.

Here are some of my afterthoughts regarding the topic of a bi-lateral deficit.

Though the late Vince Gironda didn’t believe in unilateral movements, he did emphasize the need to develop the neural connections in the non-dominant limb. To do this he would try to concentrate on slow, count-to-six bilateral reps while feeling it more (i.e., as if mentally directing the nerve force to that side) on the weaker side.

Also, though he didn’t believe in lifting unilaterally, he did believe in using the non-dominant side, say your left hand and left side if you were right-handed, for ordinary tasks such as combing your hair, picking up an object, etc. to develop the neural pathways for that side, which would then “catch up” (theoretically) to the dominant side as he continued to do bi-lateral movements. Interesting, no?

OK, it seems that many bodybuilders, as I mentioned previously, find one of their upper arms out of balance with the other. Here’s a cool little routine to correct such a deficiency.

One-Limb (Biceps blasting) specialization

Here’s a basic example of one-limb specialization for the biceps of the right arm. Place an 18-inch anti-burst Swiss ball on top of a flat exercise bench.  Choose a dumbbell that you can curl a 4-6 rep maximum on the 45° side of a Scott Preacher Bench. Set the dumbbell on top of the bench next to the Swiss ball.

Next scrounge up a heavy-duty canvas or cotton lifting strap. Thread the strap tongue through the stitched loop at the other end. Next, put the opening of the strap over the hand and place it an inch above the bony prominence of the wrist (doing so prevents the strap from slipping down the wrist and eliminates the onset of overstretched ligaments) then pull the tail end of the strap so that the opening fits snugly.

Make sure the length of strap tongue is hanging in the same direction as the thumb (i.e. palm side of wrist).

Grasp the dumbbell in your right hand, (Don’t wrap the “spotter strap” around the bar. Just let it dangle off your wrist as is.  You’ll understand why in a moment.), and lean over on top of the Swiss ball far enough so that the back of your upper arm is braced on the ball in a perpendicular or vertical position to the floor.

Begin doing timed/rhythmic reps of 5 seconds starting from the top of the contracted curl position down (negative phase of the rep) to full extension than 5 seconds curling the dumbbell all the way back up (positive phase of the rep) to the top of the curl. Repeat.

As the biceps begin to fatigue reach down with your left hand and grab the end of strap tongue, like you would a hammer, on the curling arm and self-assist.

(Judiciously pull the strap toward you) through the sticking point only, grinding out 2-3 more reps.

Now roll or shift backward on the Swiss ball so that your right upper arm is almost parallel to the floor. The tension or loading parameters on the biceps change favorable, due to the new angle of arm orientation and you should be able to do a few more reps on your own or self assist again with the lifting strap.  Do 3-5 sets resting 60-90 seconds between each.

The “spotter strap” isn’t just limited to its use in the above exercise. Two of them can be used when doing Incline or Flat Dumbbell Presses.

The trainee should have the straps around his wrists with the tail ends of the straps facing the inside of the forearms

Initially, the spotter holds the ends of the straps, lightly, between the index fingers and thumbs. When the trainee reaches positive (concentric) failure, the spotter should then grip the tail ends of the straps as tightly as possible and very judiciously pull upwards helping the trainee complete the rep(s).

Trailing-thought: Here’s a tidbit on one-limb training. Vince Gironda tried for one-year training the non-dominant side of his body with specific exercises yet reported no change in strength or size. Mike Mentzer, on the other hand, tried extra one-armed exercises for the non-dominant bicep that was lagging and it helped. Also, the old-school strongman tradition and lifters did occasionally try to bring up their non-dominant sides with one-sided exercises or single dumbbell lifts.

So it seems that, despite Vince’s unsuccessful experience training the non-dominant sides singly, there is at least the physiological possibility, at least through anecdotal evidence, of developing the non-dominant arm, leg, lat or shoulder—any muscle group, through specific, unilateral movements or exercises. One other thought. Always do 3 sets on the non-dominant side to every 1 set of the dominant side.


Dennis B. Weis is a Ketchikan, Alaska-based previous top-level titled Power-Bodybuilding champion. He is also a hard-hitting, uncompromising freelance professional writer and investigative research consultant in the fields of bodybuilding, nutrition, physiology, and powerlifting.  During the past three decades, he has established a small but dynamic one-man business to service male and female bodybuilders, fitness buffs, and powerlifting enthusiasts of all types with very personal (one to one or mail order), and highly professional instruction on all phases of physical excellence.  He has coached literally hundreds of select clients, one of the most notable being a personal training advisor to the 1983 Miss Minnesota winner.  One of the training tools he uses as a personal trainer is the revolutionary and famous Samra R.E.S.T. Principle.