The Strength Deficit as it Relates to Tennis

WeddingMy wife and I workout together in our cozy little home basement gym.  She has been crushing it for some time now and getting strong!  She normally doesn’t ask too many questions and just does what I program for her.  And I do have a method for programming workouts that involves what I am about to tell you about.

However, the other day she decided to do one of those follow-along video workouts. There was a lot of plyometric jumps involved which sparked some conversation over dinner about a little known concept called the Strength Deficit.  I am going to simplify the concept for you and if you are a tennis player it is absolutely critical to maximizing performance through off court training.

There are two kinds of strength you need to understand before we can move on to defining the strength deficit.

The first type is Absolute Strength.  This kind of strength is the absolute maximum amount of contractile force a muscle is capable of producing involuntarily.  In a laboratory setting we could stimulate your nerves with an electrical impulse causing the muscle fibers to contract.  In doing this experiment one could theoretically measure the absolute maximum contractile force your muscles are capable of producing.  Absolute strength is closely related to the size of the muscle fibers.  In other words, the larger the muscle is the greater the absolute strength potential.

The second type of strength is the Competitive Maximum.  This is the maximum amount of contractile force a muscle can produce voluntarily.  In other words this is the force you are capable of creating under your own control.  The competitive maximum is related directly to your central nervous system (CNS).  The stronger the impulse your can send through your nerves to the muscle fibers the more forcefully you can get them to contract.

So now that you understand that the absolute maximum is involuntary and the competitive maximum is voluntary we can get to the Strength Deficit.  The strength deficit is simply the difference between the two.  It should be noted that the absolute strength will always be higher than the competitive maximum because you will always be able to involuntarily contract muscle fibers to produce more strength compared to what you can do voluntarily.

Strength Deficit

What the strength deficit tells an athlete about their current state is amazingly insightful.  And if you know how to interpret the information it gives you a roadmap for how to continue making strength gains.

Here is how to interpret the strength deficit…

If the competitive maximum is close to the absolute strength you have a small strength deficit. A small deficit means that an athlete is able to send strong messages to the muscles and stimulate a strong contraction.  This is a very good sign because it means they are capable of utilizing most of their capacity for strength.  If an athlete with a small strength deficit wants to improve they need to focus their efforts on muscle hypertrophy or growth in order to raise the level of absolute strength.

If the competitive maximum is further from absolute strength you have a large strength deficit.  This means the potential for strength is there but the CNS is not capable of creating a strong enough signal to excite the muscle fibers to utilize it.  This tells an athlete they have room for strength gains without putting on more muscle.  Gains can be made by specifically designing explosive training sessions to stimulate CNS development.  Focusing on gaining more muscle mass will only increase absolute strength and the strength deficit further.

Now before I go any further the strength deficit is a fairly advanced concept and I do not want you running out and applying this to kids or beginners.  You really need to know what you are doing and this is just a overly simple blog post explaining the bigger concept.  If you want more information I recommend reading a highly complex book translated from the work of Russian Sport Scientist Yuri Verkhoshansky, Super Training.  With that being said if you are just getting started lifting weights you will see improvements in both absolute strength and competitive maximums quickly.  Beginners just have more room to make adaptations and improve.  However, if you are hitting plateaus, it is a good idea to look at your strength deficit and see if you should focus your efforts on gaining more muscle size and absolute strength potential or finding ways to stimulate the CNS and its ability to maximize muscle fiber contractibility.

Now think about a competitive tennis player’s needs…

First, tennis players need explosive and powerful muscle contractions.  They need to swing the racket with amazing accelerations and speed.  Players need to be able to sprint, change directions, and reaccelerate again.  These skills require a great deal of power without having an enormous body building style muscular frame that can slow an athlete down.  By now you should be able to guess that tennis players should have a small strength deficit.  Tennis players want to be able to maximally contract the muscle fibers they have.  That is not to say that there is never a time to build bulk and absolute strength because there is.  However, once muscle hypertrophy or mass is gained it should be followed up with a block of training to stimulate the CNS to utilize that new found strength potential fully.  Players like Djokovic, Nadal, and Federer are incredibly strong and I would bet they also have a small strength deficit.

Questions or comments leave them below and I will be happy to answer them.

4 thoughts on “The Strength Deficit as it Relates to Tennis

  1. Jamie Brause

    This is is a great article that really helped me understand the difference between a large and small strength deficit. I’m reading through “Supertraining” currently, and in the section where he initially discusses the SD (pg 7-8) Verkoshansky outlines a test where you compare a vertical jump with a counter movement to a vertical jump without a counter movement. A small difference between the two jumps suggests using plyometric methods in training while a large difference suggests using muscle mass and strength building techniques in training. This seems counter-intuitive to what he later suggests and what you outline in your article, namely that a small strength deficit suggests building muscle/strength and a large deficit suggests using plyometrics. Am I wrong in equating a small difference in jump heights with a small strength deficit and a large difference in jump heights = a large strength deficit? Sorry if this is a large question for the comments of a blog post but any help you could give me in understanding the concept would be greatly appreciated!

    1. Alex Slezak Post author

      First thanks for reading my blog. I truly appreciate all the followers.

      What Dr. Verkhoshansky is saying does seem counter-intuitive but it is correct. You should always be able to jump higher using a counter movement (dipping the knees, depth jump, bounding, etc.) that you would be just from a static position. The reason being that when you have a counter movement you utilize the elasticity of the connective/muscle tissues and utilize the stretch shortening cycle (SSC). If both jumps are about the same height that tells you that the athlete is not even close to utilizing the full potential of the nervous system to contract quickly enough to utilize the elastic and SSC benefits. Applying plyometric training methods would improve the react-ability of the nervous system thus improving jumping ability. Adding more muscle mass would increase absolute strength but still would not fix the body’s inability to utilize it.

      Jumping is a unique case because you are looking at it from a perspective of a constant weight (body weight). If you were in the gym you could load up a squat rack and find a maximum eccentric load. Then find a maximum concentric load. Eccentric is pretty close to an absolute maximum while concentric is pretty close to a competitive maximum. If they are close you have a minimal strength deficit and would use methods to increase absolute strength. If they are far off you have a large strength deficit and would use methods to increase ability of the CNS to maximally contract the fibers you have.

  2. Jamie Brause

    Thank you so much for the reply, that clears up my confusion.

    How do you assess the strength deficit in your athletes? Do you typically use the eccentric/concentric squatting method?

    1. Alex Slezak Post author

      Most of the athletes I work with are youth. They are still building the foundation and everything I would plan would be individual to their needs and sport/goals. There is good training and bad training. Pretty good is not good enough so you have to be individualizing for it to be good. With that being said typically what I would do is take a block of time in the off-season dedicated to increasing absolute strength. Then follow it up with a block of time focused on more intense methods that allow the CNS to fully utilize the new found strength capacity. This would be pre-season or block of time right before the competition. The movements and methods in this block would mimic the sport exactly or as close s possible.


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