Most people start crossfit because they want to become healthier, look better, and have more self confidence.   Often times they first learn about crossfit from Youtube, or watching the Crossfit Games on ESPN.  These top level athletes have amazing physiques, rivaling natural bodybuilders.  This leaves most crossfitters wondering how muscular they can become.  Keep reading to find out where the sport is heading in terms of natural muscular limits, and the timeframe to achieve that type of development.

I’m going to be honest, and cut to the chase up front.  I don’t believe that the top level crossfit athlete will become any more muscular, naturally.  There is a fairly easy litmus test to determine how likely someone has achieved their muscularity naturally called the fat free mass index or FFMI.  Take a gander at this article to see more about it.

To review quickly, the fat free mass index is a mathematical model that says as you go above 25 on the index, the odds drastically increase that you are using some additional anabolic compounds.  It is not a hard line.  It is 100% possible to achieve a 25 or higher without steroids, for some people, but the higher one gets, the less likely you are natural.  Check out the chart below for the FFMI’s of today’s top athletes.

FFMI CF Athletes

As you can see all athletes are above 25, but does that mean that they are all juicing? Probably not.  As I stated in a previous article, natural bodybuilders from the 50’s were reaching those same levels of muscularity in an era where steroids where unknown.

Screen shot 2016-02-08 at 11.07.04 AM

Notice I say probably not.  I think you would have to be naive to think that no one is using banned substances, but these levels of achievement are definitely within the realm of the natural.  So if 25 isn’t the limit for those who happened to win the genetic lottery, what is a more reasonable cap?

For crossfit athletes I believe that given a large enough population, that you can see an FFMI in the high 27 range, or an athlete who is 5’9 and 213lbs with 10% bodyfat.  Now, this is a bit of a swag (scientific wild ass guess) but check out this graphic of FFMI’s of current and past bodybuilders.


Now, if Arnold is in the the mid 27s, then I doubt a natural crossfiter will reach higher than that.  He was one of the most talented bodybuilders of all time, and an admitted user of steroids, which were legal at the time.

Do we need to get bigger?

Realistically the top level guys have already reached a level where any further development will not becoming from protein shakes.  The real question is, does getting bigger make a better crossfitter?  The answer is, to a point.  Check this article out for the details.

Courtesy of
Courtesy of

This charts shows that for females, as their thigh circumference increases so does their back squat, up until about 23in.  The same holds true for males, except the number is 25in for the guys.  I encourage you to give the article a read, it’s pretty fascinating.  This shows that bigger is not always better, especially in a sport like crossfit where you have to haul your girthy haunches around.

The Average Joe

I know you are saying this is all well good, but statistically speaking we are all not Rich Froning, blessed be his name.  You are probably wondering how much muscle mass can we gain, and what kind of timeline are we talking about?  Check this graph out.

Rate of Muscle Gain
Y axis is lbs and the X axis is years


Muscle Gain Chart
Figured with 7in male wrist.

This graph shows that your first three years of serious training are where most of your gains will occur.  In fact for those that are past 5 years of serious training it can be a little depressing to look at your rate of return.

This is the same data from the previous graph, but it gives you the detailed gains per year.  This data is courtesy of the excellent research from Dr. Casey Butt.  I have no affiliation with him, but he does excellent research and has contributed a lot to research in this area.

Key Take Aways

This data shows that from a wholistic perspective there really isn’t much difference between a top level crossfitter and a top level natural bodybuilder.  Sure their bodies may look a little different in terms of proportionality, as I believe crossfiters have more lower body development and less chest development than most top natural bodybuilders.

It’s also important to emphasize that this article is for instructional purposes, and not meant to indict or indicate that someone is taking steroids.  Honestly, I don’t care if they are or not, and it really shouldn’t concern us.  We should be concerned with what we can achieve without compromising our health.  If you get the basics right, and bust your ass, you can take your pre crossfit physique and add about 30lbs of muscle mass.  The question is, will you do the work?

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  1. I find this story interesting since I am 50 but as a youth I was a 5’07” 137 lb Jr in highschool. I trained what people now call Crossfit before there was a “crossfit” I returned to school after summer as. 6’01 225 lb senior. I took 1 year off and began training like a maniac My max lifts were 500 lb legal powerlift regulations bench an 800 lb squat and a 700 lb bench press. But I was still runnining 5 miles every other day wind sprints for speed. By the time I was done I played Colege football at 280 lbs with a 650 lb bench 1000 lb squat and 700 lb dead. I could slam dunk a basketball and ran a 4.6 second 40. Yet when I went back home and was asked by a former classmate who was using. I said dude get the f@$k away from me. If you don’t have enough steroids in your body go play checkers. Fact is it can be done. And it can be done without drugs except 1. That is your mind that which the mind can conceive it can acheive. I am 50 now And still ride 90 miles on the weekend and do a workout most 25 year olds don’t believe I can do a seated military press of 320 lbs for 8 reps. I do intervals twice week with a self made “crossfit” routine that would make guys half my age cry. No may sound like I am tooting my horn but you don’t know me and nor do I care if anyone does. But I never tell anyone the limits are too much. Because I myself have seen it and have done it. Without drugs of any kind. But the key is not to see any limits and to have an unconquerable spirit. The mind is the most powerful thing you have. Use it.