This is the site of Brant M Cebulla. Pretty awesome.

Being tall negatively affects ability to max back squat


June 18, 2014

I’m pretty tall. Six-foot three-inches. When I do any type of squat in the gym, people sometimes remark, “Man, that’s a long way down (to hips to knees).” Conventional wisdom says, the taller you are, the more disadvantaged you are at back squatting, because you have more range to cover and more work to do.

Is this true? Sort of.

Recently I collected data on 5,376 CrossFit Open participants, including data on athletes’ one-rep max (1 RM) back squats, heights and weights, to try and see if height does affect one-rep max back squat. And if so, to try and quantify the effect of height on back squat.

Of the 5,376 CrossFit Open participants, 1,067 men self-reported their 1 RM back squat, their height and weight.

The mean 1 RM back squat (for men) was 319.7 lbs, with a standard deviation of 67.2 lbs. This means we’d expect 68% of male CrossFit Open athletes to back squat 252.5-386.9 lbs.

Here is the distribution of 1 RM back squat:

histogram-mens-squat

Note that since better athletes are more likely to self-report, the mean is probably higher than a true cross section of CrossFit male athletes.

Nevertheless, we can still look at the effect of height on back squat.

With the data from the 1,067 men, when we run a simple regression of 1 RM back squat verse height, it actually appears that height is ever so slightly beneficial – the taller you are, the more you can 1 RM back squat. The formula is:

[1 RM back squat (lbs)] = 210.56 + 1.57*[height(in)]

Here’s the scatter plot and regression line:

men-backsquat-rawdata

Although this correlation is statistically significant, it’s really not practically significant. We’d expect someone who’s 6’0” to lift about 10 more pounds than someone 5’6”, which isn’t much of a difference. So, we can conclude here that when we’re looking at the effect of height on 1 RM back squat, there’s not much of an effect.

However, this correlation is likely confounded by weight. Our taller people weigh more than our shorter people. What we really want to know is, if all our participants weigh the same, how does height affect back squat?

We can control for weight by running a multiple linear regression. When we run a multiple linear regression between 1 RM back squat, height and weight, we can see the independent effect of height. We get a formula of:

[1 RM back squat (lbs)] = 413.11 – 5.35*[height(in)] + 1.51*[weight(lbs)]

So, when weight is controlled for, increasing height is indeed disadvantageous in 1 RM back squat. This equation is both statistically significant and practically significant. If a 5’6” guy and a 6’0” guy weighed the same (and they had similar strength), we’d expect the 5’6” guy to be able to lift 32.1 more pounds due to his shorter height advantage. Thirty-two pounds is a lot – just about a half standard deviation.

Another way we can control for weight and better visualize the relationship between height and 1 RM back squat is to only calculate a linear regression between height and 1 RM back squat for men of specific weight.

For instance, only looking at men who weigh between 185-189 lbs (n=114), we see once again very clearly that increasing height negatively affects 1 RM back squat. The relationship between 1 RM back squat and height for these men is:

[1 RM back squat (lbs)] = 860.22 – 7.63*[height(in)]

And here is what the scatter plot looks like:

men185-189-backsquat

In this smaller model, we’d expect a 185 lb 5’6” guy to lift 45.78 more pounds than a 185 lb 6’0” guy. That’s a lot!

So then why does our raw data, weight not controlled for, show that height doesn’t effect 1 RM back squat?

What this data seems to suggest is that people who are taller have big frames that can put on a lot of weight and a lot of muscle. This big frame, added weight and added muscle may cancel out the negative affect of height.

In conclusion, while height negatively affects 1 RM back squat, height also positively affects weight (and ability to gain muscle?), which may annul the negative affect of height on 1 RM back squat for experienced lifters. Thus tall experienced weight lifters who have added a lot of weight to their frame probably aren’t at a disadvantage for being tall for 1 RM back squat. Conversely, tall inexperienced weight lifters who don’t have a lot of muscle suffer greatly from being tall for 1 RM back squat.

 

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Comments

  • Red

    Are taller folks faster runners? Are shorter folks better distance runners? These are the true questions! Can you tell I’m biased in my sports activities.

    • Brant Cebulla

      I’ll do some math and write a blog post on this. Look for it in the next few weeks. Cheers.

  • Don C

    I just found your website. Love the crossfit stats. Keep em coming. I especially like it when you factor in age. Being a 40+ crossfitter I want to know how I compare to peers in the same age group. Great stuff!

    • Brant Cebulla

      Don, thanks for the shoutout here. I’m hoping to get a few more of these blogs out within a month. Maybe I’ll do a big blog post on the effect of age on a variety of lifts and workouts.

  • Greg Lindstrom

    6″8 and my 1 rep max is 500 pounds…

  • Sean

    Question: why not run a hierarchical regression, entering weight first so that the effects of weight are removed and then we can see the effect of height on what’s left over?

    • Brant Cebulla

      That’s a good idea Sean. I’ll try to get to it at some point!

  • Great article. Since I’m a tall guy and a relative weak squatter compared to my deadlift it feels right intuitively. The main weakness I see in the study is that these are self-reported squats. As some of you know there’s quite a difference between the depth of a squat required to pass an IPF powerlifting judge and some typical gym rat who might think he’s doing a “squat” even though he’s 4″ above parallel at his lowest point. However the point of the article was to see if height and weight made a difference in the amount squatted and in that it was successful if one assumes the distribution of people who do gym squats vs. IPF squats is equally distributed over the total universe of the 1000+ people who participated in this study. Now, what I’d like to see is a similar study done with the dead lift and the bench press with no suits allowed. BTW I assume these self-reported squats were un-suited but that’s only my assumption. Suggestion: in future surveys please ask participants for their unsuited “raw” lifts.
    After you do the dead lifts and bench presses I’d like to see you do one with the two Olympic lifts the snatch and clean & jerk. I’m a stat-freak so I love this stuff. Keep up the great work!

    • Brant Cebulla

      Thanks Dale. Would love to look at height and weight vs. snatches and clean and jerks. I’ll try to get to it at some point!

  • Okay Brant, keep me posted if you do correlate height and weight with the snatch and clean & jerk lifts. Also would like to see the median and range of 1REM for the snatch for crossfitters. A couple more things I’d be interested in–their stats for the 100m sprint and the 5000m run. I notice that many of them have posted PRs in the 5000 on the CF web site.

  • Jafar Tabaian

    Brant – Enjoyed this and the other CF blog posts. Very nice work!

    • Brant Cebulla

      Cheers Jafar!

  • DillWagon

    Guys good article! Do you intend to consider the extra distance/work required for a single rep by a taller athlete? It’s both more difficult (to lift 100lbs 26″ than 18″) and takes longer to complete the longer distance. How can that ever factor into a sport like cross fit? I think the sport is flawed in this regard and champions will tend to be 5’4″ – 5’10” gymnast builds. Maybe draw rep lines for the lifts and big guys will be doing little munchkin reps too. Then again the genetically gifted tend to be taller and enjoy sports, so you never know. Too many factors.

    • Brant Cebulla

      Definitely–weightlifting is not a sport for all body types. But then again, not many sports are.

      • DillWagon

        I hear you about that, but it’s the cumulative aspect of a crossfit event score that doesn’t make sense as a measure imo. So like, in oly lifting you are not against a clock, and in that sense it’s fair I think. Also in Oly they have bodyweight classes. Maybe crossfit should have height classes. I have been oly and power lifting since high school in the 80s, it’s always been a part of sports with us. But the crossfit games thing is a bit or a curiosity to me. Btw I too am 6’3″ with 37″ inseam and favor deadlift, front squat, hack squat, love hex bars, sumo. I learned to back squat onto a box and back squat is always the king but yes it’s a hella long way down. And don’t get me started with toes over knees lol. I know you know what I’m saying on that! Many instructors/coaches don’t understand the context of a tall athlete (unless they are tall).

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