You are Only as Strong as Your Weakest Link

Bilateral Deficit in Kettlebell Training

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A chain is only as strong as its weakest link. This truism is also true within the “Kinetic chain” of the human body. 

It means that in any given movement, the quality, strength, speed, power and skill of that movement is going to be limited by the capacity of the weakest joints and muscles involved in the movement. The joints and connected musculature are the links in the entire chain, which is the body.


The relationship between weaknesses or deficiencies in particular links in your body is very apparent in kettlebell lifting, particular when lifting two kettlebells in the same time, such as Double Swing, Double Press, Double Jerk, and so on. The differences between the right and left arm in a movement such as the Double Press is due to what is known as Bilateral Deficit.

Bilateral Deficit explains why you cannot jump twice as high on 2 legs as you can on one leg. 

It also explains why, for example you may be able to press a kettlebell of a certain load with one arm, but may not also be able to press the same load with the other arm. Or you may be able to do 100 repetitions (or any number) with one arm, but only 80 with the other arm.

The Bilateral Deficit is largely a result of neural (nervous system) differences. In simple terms, you may be more coordinated on one side of your body than the other.

The deficit is also due to differences in your ability to stabilize one side or one segment of your body more than the other side or than a different body segment involved in the particular exercise. Or the deficit may be the result of lack of force production, strength, in an involved segment. For example in a heavy Squat, your legs may be strong enough to move 300 pounds, but you may lack enough control in the core musculature (core muscles) to be able to stabilize the body.

Therefore your core is the deficit more so than the legs. Or you may not be able to generate enough force to complete the lift due to lack of strength in the hips and low back. 

Since the bilateral deficit is one of the major limitations preventing your optimal performance, it is advisable as much as possible to work towards the development of bilateral symmetry. Meaning, try to increase the strength and coordination of your non-dominant side. One way to do this is by working on unilateral kettlebell exercises, training one hand at a time and doing equal or even more repetitions with the non-dominant hand as you do on the dominant hand. 

Another way to bridge the gap between your dominant and non-dominant sides is to train double kettlebell exercises, but stopping short of failure. Instead of training maximal repetitions, you can do many sets of lower reps, making sure that each rep is performed with strict form, done with complete range of motion and stop before reaching fatigue, so that you develop the neural skill (coordination) through movement patterning.

By doing each rep well, you develop the muscle-memory to perform it correctly and allow the stronger side to guide the weaker side, with the goal of eventually making the two sides as even as possible. It is unlikely to ever become truly equal between the dominant and non-dominant sides, however with training you can bring the two sides closer. 

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