
NFL players: height and weight over time  - chwolfe
http://noahveltman.com/nflplayers/
======
torbit
Anytime I see a post about football I wonder how it is different from rugby,
so I'll just post this intresting article

"In rugby, the only collision (i.e., running at speed for the purpose of
forcing a player to the ground) is when one has the ball. The other 29 lads on
the pitch are there for support. In American football, 21 of the 22 players
had better be colliding with someone on every down - at full speed. In
gridiron, there is collision while blocking. In rugby, the equivalent is
called "obstruction" and is illegal, thus there are far more opportunities -
requirements - for player collision in American football."

[http://wesclark.com/rrr/pads_and_helmets.html](http://wesclark.com/rrr/pads_and_helmets.html)

~~~
markdown
Another factor is the lack of a helmet and padding. Because of this, players
are much more careful when tackling. Eg:

* NEVER leading with the head, which is quite common in American Football

* There must be an attempt to wrap your arms around the player. Not doing so is a shoulder charge, and illegal.

* High tackles (above the shoulders) are illegal and can result in yellow or red card depending on severity.

* Spear tackles (picking the player up and driving him into the ground head-first) are grounds for a red card.

~~~
girvo
I'm an ex referee, used to ref first grade club and schoolboy rugby in SEQ.
I've seen first hand _why_ those rules are in place. I will disagree with
having the ball being the only collision points however: rucks, mauls and
scrums (the latter of which are neutered now) involved any number of players
but still don't quite compare to the one on one that NFL involves. Fascinating
sports IMO :)

~~~
markdown
> the latter of which are neutered now

Only if you're talking about Rugby League.

~~~
girvo
*shrugs.

The current laws have definitely changed the feel and reduced the danger when
it comes to scrums. I watch a kid taken off the field a paraplegic due to
someones foot slipping on "engage", so I don't necessarily disagree with the
laws, but you can't argue that they're not in place to slow it down and make
it safer.

------
incision
Craig M. Booth has done some very nice visualizations on this subject [1]. I
found this chart comparing height/weight of 2013 rosters by position [2]
particularly interesting and this set [3] covers a question that anyone who
has read _Outliers_ has probably wondered about.

1:
[http://www.craigmbooth.com/category/nfl/](http://www.craigmbooth.com/category/nfl/)

2: [http://www.craigmbooth.com/height-and-weight-of-every-
active...](http://www.craigmbooth.com/height-and-weight-of-every-active-
football-player/)

3: [http://www.sportsballweekly.com/the-relative-age-effect-
in-p...](http://www.sportsballweekly.com/the-relative-age-effect-in-pro-
sports/)

~~~
3JPLW
Ugh, on [3], watch out for the non-zero axes. NHL and NBA start their axes at
0, while the others do not. Very tricky, and very deceiving. I think NFL would
look very similar to NBA if plotted the same way (they're both within ~10-15%
of the expected value).

~~~
ronaldx
The author points out in the text that the NFL result is statistically
significant and the NBA result is not.

A larger random sample ought to fall closer to the line than a smaller sample:
it would be statistically highly remarkable if the graphs did look similar
with zeroed axes - the larger sample _should_ look _much_ flatter.

Starting both graphs from zero is unhelpful if the goal is correct visual
interpretation.

~~~
sesqu
One could argue that the large difference in sample sizes (more than fivefold)
justifies scale manipulation to bring the variances into line, but it doesn't
appear to me that the author normalized on variance at all (the axis should be
something like 800-2000).

~~~
ronaldx
I agree with what you say.

To correctly compare the variances, the scale should be adjusted according to
the square root of the ratio of sample sizes.

The author has not done this correctly, but I claim that zeroing the axis
would be further from the correct graph.

~~~
craigmbooth
Ah, you are correct, thank you. Apparently I wasn't thinking clearly when I
normalized the axes to have the same absolute ranges.

------
mkhaytman
I'd like to see how the general population changed in the same time, then
maybe a revision of this graph keeping it in perspective of how the rest of
the population changed.

~~~
romanovcode
I don't think general population changed at all.

~~~
lukeschlather
[http://www.cdc.gov/nchs/data/ad/ad347.pdf](http://www.cdc.gov/nchs/data/ad/ad347.pdf)

> Conclusions: > Average weight has increased dramatically in the last 40
> years with the greatest increases seen in adults. Mean BMI has also
> increased. Although height has also increased this increase has been much
> more modest.

------
S_A_P
I wonder if this has compounded the TBI and concussion issue over the years. I
think sports medicine in general has gotten much better and the average player
is probably bigger and stronger and thus able to hit harder than 20+ years
ago...

~~~
skierscott
Malcolm Gladwell has looked at this issue[1]. He sees football as being
analogous to dogfighting. Popular at the time and with fans, but the science
behind it is scary.

I've experienced a severe traumatic brain injury (sTBI), meaning I've seen
many brain doctors. I have seen a neuro-omptomolgist (brain-eye doctor) who
sees a football player who can't even add up his checkbook (meaning he can't
add, not this his checkbook is too complex). I had a therapist who dated a
college football player and eventually saw him as more of a patient than a
boyfriend.

A concussion is now defined as seeing bright spots[2] and is classified as a
mild TBI. The results from concussions are cumulative[3], and football is one
of the sports most prone to concussion[3]. A football block is defined as
being good if you see bright spots or having a concussion, and players often
play through this[4].

I'll never let my children play football.

[1]:[http://www.newyorker.com/reporting/2009/10/19/091019fa_fact_...](http://www.newyorker.com/reporting/2009/10/19/091019fa_fact_gladwell?currentPage=all)

[2]:[https://en.wikipedia.org/wiki/Concussion](https://en.wikipedia.org/wiki/Concussion)

[3]:[http://www.sciencedirect.com/science/article/pii/S0140673675...](http://www.sciencedirect.com/science/article/pii/S0140673675902883)

[4]:[http://well.blogs.nytimes.com/2013/11/05/dont-tell-coach-
pla...](http://well.blogs.nytimes.com/2013/11/05/dont-tell-coach-playing-
through-concussions/?_php=true&_type=blogs&_r=0)

~~~
silverbax88
When I was in high school I was a Division I football prospect. I had multiple
schools after me: Alabama, Florida, LSU, etc. I really wanted Miami (this was
the '80s) but deep down I really wanted to play basketball. I only got a
little sniff of DI basketball interest but I went on a football visit to
Florida and saw massive guys hitting each other and thought "I'm going to get
killed" and never took the football scholarship. I'm a big guy - 6'4", 225, I
was pretty close to that size in high school and I was a pretty angry teenager
so hitting guys at full speed was in my...well, 'nature'.

So please consider this when I say that those college guys were jacked up on
'roids' and WAAYY too big for me. I didn't take steroids in high school but I
was big enough and strong enough (and in truth, angry enough) to play against
those kids on 'roids anyway. I knew in college, I wouldn't have been.

I walked away from a certain Division I college scholarship (at the time - I
blew out my knee a year later) despite what my coaches were calling a 'no-
brainer' to play football. I've NEVER regretted it and each year that has
passed since has made me even more glad I did it.

~~~
at-fates-hands
You sound remarkably similar to what Wayne Gretzky said after he retired. The
last two years of his career, his Dad kept asking him if he was going to play
another year.

He basically said, "I don't know. Every year I go back to camp, the guys are
bigger, stronger and hit harder than last year."

When you look around the league, it's obvious how much bigger these guys have
gotten. Look at some of the current LA KINGS forwards:

Jeff Carter - 6'4" \- 212lbs

Dwight King - 6'4" \- 230lbs

Anze Kopitar - 6'3" \- 224lbs

Jordan Nolan - 6'3" \- 221lbs

I'm assuming their heights are all reflected without wearing skates, which
adds a good 2" to those heights. This is one of the reasons many pundits said
LA won the cup in 2011. Big, strong forwards and a merciless forecheck. I
still remember one of the announcers saying, "Imagine you're a defensemen and
everytime LA drops the puck into the corner in your end and you have two of
these guys hurtling towards you as you go for the puck. It's a defensemen's
worst nightmare."

~~~
dobbsbob
In hockey there's a strategy for this you both grab each other and slide in at
the same time to avoid getting killed on the boards. When Gretzky played no
other player could hit him because they didn't have the instigator rule, so if
you clobbered him on the boards the biggest goons on his team would take your
head off so the result was nobody touched Gretzky until late in his career
when they put in that stupid rule.

Hockey also has the problem of players wearing body armor now so hits are even
worse than what they used to be.

------
nubs
Very interesting how you can definitely see 3 distinct groups emerge in recent
years. I'm guessing linesmen are the majority of the group that really shifts
over to the right.

~~~
scott_s
That was my thought, too. I'm guessing the group on the far right are the
linemen, the group on the far left are the receivers, and the middle group are
those that cover the receivers.

What I find most interesting is that there's a clear gulf between the
(probable) linemen on the far right and the others. That middle ground is
probably not best suited for any role - if you're chasing the receivers,
you're going to be too slow, and if you're trying to protect or attack the
line, you're going to be too small.

~~~
dpeck
Middle group is likely to be primarily made up of linebackers, running backs,
with a few of the larger tight ends there as well.

These players, while having some responsibility in the passing game are
primarily involved in either running the ball, or defending against the run.
And having a bit more mass there is very beneficial, but they still need to be
able to have the speed to be able to work horizontal across the field and
sometimes be quite a ways away from the line of scrimmage by the end of the
play.

~~~
maxerickson
incision's link, in a top level comment, has a plot that distinguishes
positions. (Modern) Tight ends are heavier than linebackers, then
quarterbacks, then running backs.

------
bane
I like how in the 80s, height stopped increasing, but weight kept increasing,
and a little blog of the highest weights just shot out to the right.

I live very close to one of the pro team's training camps, and see the players
around town every once in a while. Professional athletes like this are truly
in a league of their own. You can go to any random gym and look for the guys
there in peak physical condition. The pro-NFL guys stand out easily in a crowd
of gym guys. Not just the really huge guys, but you can spot one of the
"smaller" players from a mile away. Their musculature and body motions are
simply superhuman. It's something very very hard to see on TV when they're
surrounded by their peers.

~~~
smky80
Not all of them though.

[http://theloveofsports.com/blog/wp-
content/uploads/2013/09/t...](http://theloveofsports.com/blog/wp-
content/uploads/2013/09/tom_brady_nfl_draft_combine_2000.jpg)

Been looking for a Sebastian Janikowski draft picture but couldn't find one.

------
derekjobst
What's interesting is before the 1970's it appears as though there is just one
group of players, at which point they become three. Then, over the following
40 years these groups seems to just get heavier - most likely a response by
teams to maintain heavier players than their opponents in certain positions.

While the general growth over time makes sense, I wonder what caused the shift
specifically in the 70's.

~~~
maxerickson
Everybody is saying steroids, but another thing that happened around the
1970-80s is that college football became a much bigger business:

[http://en.wikipedia.org/wiki/College_football_on_television#...](http://en.wikipedia.org/wiki/College_football_on_television#Decentralization)

~~~
derekjobst
Oh, that is very interesting.

------
Florin_Andrei
Fantastic viz.

So, they pushed up on the height parameter, but hit a ceiling.

Then they've started to push further on the weight parameter, where the
"ceiling" is more flexible.

You can bulk up to some extent, but your height is pretty much a given.

------
Theodores
This article serves to illustrate how different America is from the rest of
the world. Outside America nobody knows what NFL is beyond that it is some
strange variant on the football theme, related to football in no more way than
how a whale is related to a dog.

Then there are 'customary units'. Outside America nobody knows what a pound of
weight is, is that pound of 'customary units' the same as an 'Imperial' pound?
Nobody knows, particularly when applied to body weight. The height situation
is better, there are places like the UK where Imperial measurements are used
for height, but, in mainland Europe and beyond, I doubt anyone knows what 6'
tall means.

I imagine that in America it is hard to see this perspective on how different
America is, and, most of the time with most HN stories there is no cultural
barrier to understanding things, yet this story is an edge case and reminds me
how different American culture really is.

~~~
mahranch
> Outside America nobody knows what NFL is beyond that it is some strange
> variant on the football theme

I think this is _extremely_ misinformed. Did you know that there is a world
cup for gridiron football? It's the IFAF World Championship. And believe it or
not, Japan is ranked 1st right now, with the U.S ranked second. American
football was pretty well known in Japan and before I left, was becoming
increasingly more popular among high school and college aged kids.

The also continually sell out games in London every year. The broadcasts there
get extremely high ratings. I think the "myth" that the rest of the world
doesn't know what American football is died sometime in the 90s. It's been on
the rise globally: [http://www.nytimes.com/2012/11/13/sports/football/13iht-
nflc...](http://www.nytimes.com/2012/11/13/sports/football/13iht-
nflchina13.html?_r=0)

------
AlexMcP
What sort of method would be used to cluster those, statistically speaking?
Like, given a data set like that, how would you determine if the distribution
is multi-modal or unimodal?

~~~
GrantS
Mean shift clustering, for one. This short PDF provides better insight than
wikipedia. Does NOT require you to specify the number of clusters like in
K-means:

[http://homepages.inf.ed.ac.uk/rbf/CVonline/LOCAL_COPIES/TUZE...](http://homepages.inf.ed.ac.uk/rbf/CVonline/LOCAL_COPIES/TUZEL1/MeanShift.pdf)

[http://en.wikipedia.org/wiki/Mean-shift](http://en.wikipedia.org/wiki/Mean-
shift)

Example python code using scikit-learn: [http://scikit-
learn.org/stable/auto_examples/cluster/plot_me...](http://scikit-
learn.org/stable/auto_examples/cluster/plot_mean_shift.html)

~~~
AlexMcP
Awesome! Thanks for the knowledge

------
amiramir
I'd be interested in a similar chart for rugby union where my guess is that
the increase in height and weight has happened more quickly. It's just a hunch
but I am guessing that overall size in rugby has increased dramatically since
the sport went professional in 1995.

~~~
arethuza
Here is an interesting article on the size of rugby players:

[http://www.bbc.co.uk/blogs/legacy/tomfordyce/2012/03/land_of...](http://www.bbc.co.uk/blogs/legacy/tomfordyce/2012/03/land_of_the_rugby_giants.html)

------
robotcookies
How accurate are these figures? I know that many teams will inflate the posted
weight and height of their players. There is no regulation requiring that the
publicly posted figures are accurate so they nudge them higher for
psychological effect.

~~~
nbardy
That is a problem in college, but once they hit pro they've gone through the
combine and they are measured.

------
1238488462662
Steroids. Relevant:
[http://en.wikipedia.org/wiki/Bigger,_Stronger,_Faster*](http://en.wikipedia.org/wiki/Bigger,_Stronger,_Faster*)

~~~
logn
Steroids don't make you taller. Also if you devote yourself to nutrition and
weight lifting, as a 6 foot male it's not too hard to exceed 200 pounds. I
don't doubt steroids play a part, but there are many other factors (in
addition to just the fact that football became a national obsession so is
attracting more potential players).

And prior to 1940, the same players played offense and defense, along with
limited substitutions. These days, players not only play one position but are
often substituted out depending on the particular play or formation. That lets
players specialize and, I'd argue, put on body mass for their more limited
role.

~~~
menssen
Also if you _habitually neglect_ nutrition and weight lifting, as a 6 foot
male it's not too hard to exceed 200 pounds.

------
DavidSJ
It seems to become bimodal towards the last decade or two. Any idea as to why?

~~~
diziet
Separation between light and fast players/roles and heavy and powerful
players/roles.

~~~
brownbat
I'm mostly stuck thinking about this in terms of tanks and spellcasters thanks
to PA:

[http://www.penny-arcade.com/comic/2013/01/18](http://www.penny-
arcade.com/comic/2013/01/18)

------
mathattack
I find it interesting that a break appears in 1993 where the Extremely Huge
(lineman) separate from those merely Very Large.

My old man once commented that he his Big 10 college alma mater once had
someone on the football team whose only virtue was being 275 pounds.

------
moron4hire
My biggest take-away: the smallest guys today are in the median of players
from the 20s. The biggest players from the 20s would only be in the lower
quartile of the players today. There is nobody today as small as the smallest
players from the 20s.

------
nichochar
Fasinating, reminds me of a great TED talk about this: "Are athletes really
getting bigger, faster, stronger?"
[https://www.youtube.com/watch?v=8COaMKbNrX0](https://www.youtube.com/watch?v=8COaMKbNrX0)

tl;dr: no

~~~
romanovcode
Don't forget about steroid usage since 1950's. Even olympic athlete trainers
don't hide this fact.[0]

[0]
[https://www.youtube.com/watch?v=VIiIKB7uDCc](https://www.youtube.com/watch?v=VIiIKB7uDCc)

------
tohmeiphun
The player equipment has also become much more advanced, but is it helping or
hurting? They should go back to leather helmets and no pads (like rugby) and
see what happens.

~~~
rasz_pl
+1 this. My guess is one season of natural selection would be enough to change
players behaviour.

------
cafard
One could probably bring the weight back down by strictly limiting
substitution. Until the late 1950s a lot of players played on both sides of
the line of scrimmage.

------
panzagl
The WWII years ('42-'45) have more of a range than before or after, presumably
because of the draft.

------
markb139
I wonder what the same animation would look like for sw developers. Im 6ft6
and 252lbs. Though being a Brit I'd say 6ft6 and 18 stone or even 2m and 114.5
kg.

------
andrewgjohnson
Interesting, by position would probably be more interesting. Or "position
group" e.g. DB's, CB's & S's

~~~
valarauca1
If they position by color gradient, color 'darkening' with contraction. QB's
blues, linesmen red, receivers green, etc.

------
Evgeny
Anyone can recommend an API or tutorial on how I could create similar
visualisations myself or use a third party tool?

~~~
user24
Look at D3 or Raphael :)

------
guelo
Seems like they don't have any use for 280 pounders nowadays.

~~~
bergerjac
too heavy for a TE, too light for an OL/DL

------
Volscio
The visualization looks like Conway's game of life.

------
kghose
Apparently the breeding program is working.

