NFL players: height and weight over time

[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

[bps4484]

I think there is something even more fundamentally different between football and rugby that lead to bigger, head on collisions (and what makes the padding in football a necessity).

Specifically, in rugby, the way you maintain possession of the ball is by falling properly with your body in front of the ball (not lunging forward) and making sure your team is around you so you can ruck[1] properly and continue on with the ball.

In football, there are 4 attempts to get 10 yards and you want to make sure with each of those chances you absolutely get the most amount of yardage (running backs are taught to always fall forward, defenses are taught to run people over head on, etc) and of course that doesn't even mention the forward pass where there is an incentive to hit a player as hard as you can to "separate the man from the ball" (this is something that is drilled into you as a defensive player).

[1] for people who haven't watched rugby, http://www.youtube.com/watch?v=2htLUcu-lcs is a video which explains what rucking is. Note how it's not important that you lunge forward for an extra yard. In fact, it's stupid to do so! The defense would allow you to do that, and then just take the ball from you once you're down.

This is also just my understanding of rugby having watched it from a distance. If I'm incorrect about my assumptions of the rules I'm happy to be corrected.

[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.

[slyall]

The local paper posted an article a few days ago about relative sizes of Rugby players ( The "All Blacks" are the New Zealand national team ) compared to 20+ years ago.

http://www.nzherald.co.nz/sport/news/article.cfm?c_id=4&obje...

[bane]

One of the few impact comparisons I've seen.

https://www.youtube.com/watch?v=W7tGY-VDx3o

[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/

2: http://www.craigmbooth.com/height-and-weight-of-every-active...

3: http://www.sportsballweekly.com/the-relative-age-effect-in-p...

[mbauman]

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).

[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.

[jusben1369]

Yes! That's what I came here to type. What does it really mean if this actually tracks to the general population?

[romanovcode]

I don't think general population changed at all.

[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...

[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.

[hluska]

I am a baseball fan so I am biased, but when I saw those groups form, my first thought was performance enhancing drugs. I sure hope there is another reason...

[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...

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

[evilduck]

I used to live a couple miles from the Saints training facility and shopped pretty frequently at the grocery store across the street where encountering players was somewhat common.

I'm 6'4", 215lbs and don't often experience what being small feels like... except when I'm standing next to NFL linemen. They're just huge.

[supercanuck]

>and a little blog of the highest weights just shot out to the right

Offensive Lineman and Defensive Tackles.

[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#...

[altcognito]

So, weight training and anabolic steroids really take off in this time period. The added strength probably means players can still move that massive body weight at the same speeds (or, in most cases, much, much faster) than someone who doesn't add bulk muscle as modern NFL players do.

NFL players are absolutely, positively freakishly fast for their size.

[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...

[rlanday]

Why are you complaining on an American internet community about our choice of unit system and the terminology we use for naming different sports? The United States has distinct cultural features just like every other country. I waste a fair amount of time arguing on the internet, but I’ve never felt the need to find articles about European football and complain that people shouldn’t call soccer “football” because American football is better, that people who use the metric system feel compelled to tell other people they’re stupid for using different systems, and that Europeans are jerks for charging for restroom access and restaurants not giving free soda refills.

[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://en.wikipedia.org/wiki/Mean-shift

Example python code using scikit-learn: http://scikit-learn.org/stable/auto_examples/cluster/plot_me...

[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...

[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*

[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.

[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.

[vpontis]

I noticed that too. It looks like their is a further specialization into linemen and "skill" players. Linemen need all of the weight they can get where "skill" players want to be bigger and stronger to some extent but still need to be agile.

[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

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

[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.