How Big is He Now and How Big Will He Get?? – Taking Testing to the Next Level

How Big is He Now & How Big Will He Get??

From a purely athletic point of view the #1 thing that we are looking for when selecting a baseball player is their ability to produce power.  The kind of power that we want for throwing a baseball really hard can be produced in different ways which is why tall skinny guys can throw just as hard as shorter guys with more muscle.  We explored this subject when we discussed the concept of building “Athletic Profiles” based on each athletes results of their tests.

While there are a couple of different ways of producing these high levels of power the best way to increase power in the future is to get bigger and/or stronger.   So we will look at some tests and assessment which will measure specifically how big and strong an athlete is now and how much potential they have to get bigger and/or stronger in the future.

Seeing if an athlete has some room for growth or untapped power is huge because scouts and coaches are always trying to look for potential.   If we can get them bigger and/or stronger their ability to produce more power will automatically increase.

I am going to rattle off a bunch of other tests and assessments that I would run a baseball player through when evaluating their athletic ability.  Then I’ll rant about why I think it’s important without going into a ton and ton of detail because each one can be it’s own subject for article.  You will see a full list at the bottom of all the tests which wouldn’t take more than 5 minutes if you know what your doing and have experience.

You might think that this is too many tests but as long as I can get some good information I think they are worth it.  I think that any team that is going to be investing time, energy and/or money in a player would want to get as much valuable and useful information as possible.   

My criteria of knowing if an assessment or test is worth my time and effort is if it can provide me with:

  1. Results that can predict baseball playing ability
  2. Provide clues about how to better train each athlete

Some of these tests require either some equipment or skill in order to gather the information accurately which leads to the next point.  Because some of these tests are harder to implement the results that one person gets compared to another might be slightly different and as a result these types of tests don’t get used in research which means there isn’t much data out there to compare and rank players against.

That being said these tests are still very valuable.  If you build up your own data base as an organization with some standard protocols of how you do the tests the information that you gather can be used in both selecting a player and also designing them a customized program to improve their athletic ability to play baseball.

So here are my tests to see if a player can get bigger and stronger.  Let’s start with the bigger part.

How big is he and how big is he gonna get??

If someone is going to get bigger it would be because they got taller and/or heavier.

We know height and weight are important and there’s a lot of research to back that up. But if all we do is look at these two stats then we are missing the out on a lot of information.  Height and weight are just sum totals that we see on the surface but what makes up these totals can help use determine if a player has room for growth and if their height and/or weight can be used for increased throwing velocity.

If we peel back a couple more layers and dig deeper we can get some valuable info and that’s where we get into antropometrics which is just a fancy word that measures body size and portion.  Anytime a scout or coach says someone has a “big league body” or has a “good frame” they are talking about antropometrics from a very subjective point of view.  By measuring more than just height and weight we can get some really valuable and quantifiable information that can tell us exactly where a player is today but more importantly where a player might be in a couple of years.

Let’s look at height first.

How tall are they and how tall are they gonna be??

If you want to throw a baseball really hard it helps to have the right kind of levers and taller players have this advantage.  But be careful because some of the most valuable levers for throwing velocity don’t contribute to standing height so they would be missed if this was the only test.  For example there are some studies that have looked at other throwing sports (waterpolo, handball, cricket, javelin) that have found that specific physical attributes like arm span, forearm length and shoulder width were attributed to increased throwing velocity.

Simply measuring someone’s arm span while also making note of the forearm length and shoulder girth gives you a lot of great info. While your at it you can measure hand size which is another great attribute for throwing hard and creating spin.  Look at the picture below of Pedro Martinez and his disproportionately large hands!!!


Since I am already measuring hand size i might as well look at the length of the individual fingers to get some finger length ratio’s   There is a research about the specific ratio between finger lengths which can indicate natural levels of testosterone.  It has something to do with the amount of testosterone the fetus receives during pregnancy.  You don’t to know anything more than higher levels testosterone are a good thing when it comes to building muscle mass as well as one’s competitiveness.  How wouldn’t want someone that’s both muscular and competitive.


While we are on the topic of ratio’s there are some other’s that also provide great info.

The arm span to standing height ratio is very important especially when looking at younger athletes.  The reason for this is because the limbs typically grow first so the larger the difference between the two heights (arm span>standing height) means that this player has more room for overall growth.

This ratio along with a seated to standing height ratio gives us an idea of how old this player is biologically rather than chronologically.  Chronological age is just based on how old someone is based purely on a calendar.  Biological age on the other
hand shows us how far along someone is in their maturation process.  Its estimated that up to 45% of adolescents are either “later bloomers” or “early bloomers” compared to their chronological age.  Its also been reported that the biological age can be up to three years different than the chronological age in either direction meaning a 15 year old can look like a kid anywhere between the ages of 12 and 18 based on their development.


Scouts and coaches in the past have always looked at the players parents to subjectively guess what kind of growth potential there is while also making note of things like facial hair to see where a player is in their developmental timeline.  The seated vs standing height has some research to back it up to give it a more quantifiable and educated guess.  If you have that player’s previous height at 3,6 and 12 months ago you can get an even better idea as to where this player is on their growth cycle. 

This is becomes more important as you deal with younger and younger athletes.  Considering that College teams are starting to look at players as young as freshman in high school while MLB teams can sign international players when they are 16.5 years of age this kind of information can help you find those late bloomers.  

How much do they weigh? How much are they gonna weigh?

Taking into consideration how much someone weighs is more important than most people think when it comes to baseball.  Time and time again research has shown that those with higher body weights throw harder.

A lot of young baseball players simply aren’t heavy enough to produce the kind of power needed regardless of how much speed/velocity they can pump out.  There is a point of diminishing return when it comes to increase body weight and throwing velocity and that’s when someone can’t control their mass which usually means that too much of their body weight is composed of fat rather than muscle.

So ideally we want both body weight and body fat to be within a certain range.   To measure body fat and mass you could easily get a scale that does both. 

Here are some averages of pro players that have been published in the past.

Level and/or Age



Body Fat%

Rookie Ball




















Pro (16-19yrs)




Pro (20-22yrs)




Pro   (23-25yrs)




Measuring body fat with the scale is quick and easy but it’s not that accurate (hydration levels can vary your results) and it doesn’t tell you where this athlete stores their body fat which is where body fat calipers come in to play.



This is a tool that does take some learning and practice in order to master not to mention the permission to pinch someone’s body fat.  The reason why you might care about where a player stores their body fat is because it might tell you something about their hormonal profile. 

This information is based on a lot more anecdotal rather than peer-reviewed research however there are a couple of papers that back this theory.   I’ve learnt about it from Charles Poliquin who refers to your fat distribution as your bio-signature.

Higher levels of fat on your chest and triceps for example it is thought to indicate a suboptimal ratio of estrogen to testosterone since these are two locations where women tend to have more fat then men.  Fat around your belly button is also thought to indicate higher levels of the stress hormone cortisol.  The ratio of testosterone to cortisol is one of the best markers of performance and recovery is the exercise science world.


Hormone analysis through either blood or saliva is the traditional way and is a lot more accurate and expensive.

Getting a player that has a bad hormone profile could mean that there is some area for improvement because if they can sort this out they will undoubtedly add muscle mass. Players that aren’t genetically gifted to have great hormone profiles in the first place will benefit from programs that are specially tailored to their unique needs which if your team can provide them with you would see an immediate return on your investment with a  better athlete.

Better training when combined with the right mixture of sleep, nutrition, mind set and supplements (legal ones) can help shift your body from a muscle burning and fat producing machine into fat burning muscle producing machine.  Click here to learn more about testosterone, growth hormone, cortisol and insulin.

Putting it all together:

So when it comes to physical characteristics I would measure following which shouldn’t take more than 5 minutes.

  1. Standing Height
  2. Seated Height
  3. Arm Span
  4. Shoulder Width
  5. Forearm Length
  6. Hand Size
  7. Ring Finger
  8. Middle Finger
  9. Index Finger
  10. Weight
  11. Body Fat Percentage (electronic Scale)

Body Fat Distribution

  • Triceps
  • Chest
  • Abdominal (belly button)
  • Supra Illica (love handle)
  • Subscap (bottom tip of shoulder blade)
  • Thigh
  • Calf

Graeme Lehman, MSc, CSCS


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