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."
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.
You are essentially correct - rugby is a game of field position and there are enough players on the field that you can simply lateral the ball to the next man before taking a huge hit and play continues. Having played both American football and rugby, I will say the individual collision is more spectacular in football but getting rucked in the head by 3/4" metal spikes is no walk in the park. I was always more sore after a football game but had far more cuts and bruises after a game of rugby.
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 :)
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.
See my sibling comment to you, markdown. I think the helmet and padding came because of the rules, not the other way around.
Also, just an FYI that high tackles (at the head) are also illegal in football. The "head tackle" was made illegal after being popularized by Dick "Night Train" Lane. See this, https://www.youtube.com/watch?v=vPm-6ZlTM5o, for the savagery of yesteryear.
Being a big fan of football I have sometimes wondered what the sport would be like if they slowly phased out the protection. You are taught early on to put your head down and drive your shoulder through the target, but I imagine this would be different if your head and shoulders weren't the most padded parts of your body.
Quick clarification point because other Americans like myself might initially be confused - in the NFL "spearing" is different than "spear tackling" in Rugby, and is actually what you describe in your first bullet point; a tackle where you lead with the head.
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.
I like to say that there is no science in Sports Science, that said I was impressed with how much force Ray Lewis was able to generate with about a 4' head start in this episode:
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.
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).
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.
With broad correlational data like this, it's important to know what significance threshold is being used, and what the significance value actually is. There are many possible analyses that can be run, and there will be some subset of those analyses that produce significant results by chance, which is why you need hypothesis-driven analysis and/or very conservative corrections for post-hoc analysis.
Without the details, we can't evaluate significance claims.
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).
I generally feel that zeroing the axis is never wrong, but yes, in this instance a (properly) cut axis would be better than correct. However, it should be apparent at a glance, and the presence of the other two graphs complicates things as well, so I have some reservations.
For number 3 and NBA players, wouldn't the fact that having to be so tall would trump the age effect? Being 7 feet tall is an extremely rare statistic event, so whether the player is born in January or December isn't material.
A lot of this can be explained by the differences in the leagues and how they group kids by age.
NHL: You play by year. An under 17 team (U17) this year will have everyone born in the 1997. If you're born in Jan-May, you're already 17 playing in the under 17 league. This is a small advantage. It is a huge advantage in the U6 league and gets the earlier born into club teams and youth programs where they receive special attention and better hopes of a professional future. This same model applies to soccer.
Basketball: Basketball is unusual in that a tremendous amount of the players growth consists of playing pick up games against other players. Playing against better players is simply a matter of being able to keep up. It is the closest to a meritocracy among these sports.
NFL: Football is unusual in that it is not club dominated but scholastic in nature. The age cutoff is typically Sep 1st, or nearby. I would be curious about those in the July/Aug band and how many were held back a year so they could be older
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.
> 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.
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...
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].
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.
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."
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.
I know a few people who do neuropsychological testing (testing IQ, various kinds of memory, spatial reasoning, attention, and so on). Some college athletes are now getting "before" tests, as a baseline to evaluate the severity of damage after any subsequent concussion. One tester says she's seen players attempt to do poorly on the "before" tests, so they'll be able to keep playing even after a concussion impairs their cognitive abilities.
Why can't one sell their the cognitive ability if they choose to? If the player is "smart" enough to cheat the test then ultimately it is their choice. Society has deemed their muscles more valuable then their intelligence and I don't think we would be turning towards them for their thoughts on optimizations for database wrappers.
I didn't say they don't have the right to choose (though there's a discussion to be had about how informed their consent really is), I just said that their choice horrifies me.
Coincidentally, I've worked with a former Pac-12 football player (who left the game after I think freshman year), and in fact I have sought out his opinions on optimizations for database wrappers (among other subjects). Beware of who you write off with your stereotypes!
Well, it depends. If you believe that Armin Meiwes https://en.wikipedia.org/wiki/Armin_Meiwes is wrongly imprisoned and must be released, then sure; you also win the who's-the-most-consistent-libertarian contest. On the other hand, if you believe that humans possess certain unalienable (which means not revokable, and not relinquishable, even voluntarily) rights, then the fact that the football players are volunteering for brain damage is not necessarily enough to make it okay.
I don't want to live in a society where people are told it's okay to have their bodies destroyed to get a living (or a scholarship) or to satisfy the market (for a prestigious football team that sell tickets). We shouldn't strive for that.
Ranting:
> Why can't one sell their the cognitive ability if they choose to? If the player is "smart" enough to cheat the test then ultimately it is their choice.
That's a catch-22. If they were smart, they wouldn't sell their cognitive ability.
> Society has deemed their muscles more valuable then their intelligence and I don't think we would be turning towards them for their thoughts on optimizations for database wrappers.
So when the economy isn't good we should sell our organs because society deemed our body parts more valuable than our well being ?
I agreed with your moral position that it's the players right despite the fact that it's wasteful.
Your last sentence is out there though. We're talking about kids in college, no one has put a price on their intelligence yet. Also unnecessary to imply that football players wouldn't be able to do anything useful with their intelligence.
Nice anecdotes. Your comments and links are good at triggering fear, but the data doesn't back you up that football is an usually dangerous sport.
Women's soccer has a higher rate of concussions than men's football at the collegiate level, and it has 75% of the rate at the high school level [1]. Similarly, men's college soccer has a higher rate than high school football. In fact, football is higher than the average sport (high school or college) by less than a factor of 2, an average which includes non-contact sports like volleyball.
Will you be preventing your girls from playing soccer?
Yes, football has a somewhat higher rate of concussions than most other sports, a fact that should be considered before participating. And yes, the recent improvement in concussion treatment and monitoring is a great thing which will naturally focus on football since it has a higher concussion rate and since more US high schoolers play football than any other sport by far.
But the idea that football is in its own category of danger is ludicrous. If you're withholding your children from football, you should almost certainly be withholding them from all contact sports.
You're saying that Football (where hitting another player is illegal) is as dangerous as American Football, where hitting another player with the full weight of your body at high momentum is the point of the game for most positions.
Does not compute.
From the study you linked to:
> Contact with another person was the risk factor responsible for most concussions among high school athletes.
You could play an entire season of Football without ever coming into contact with another player. Unless you were a Marvel superhero, that wouldn't be possible in American Football.
I skimmed the study you linked to an the conclusion was merely that Football and American Football had the highest rates of concussion... compared to what... track and field athletics? DUH!!
My understanding is that the concussions in soccer come from direct head-to-head collisions (which are not cushioned by helmets) and from heading the ball (which is moving significantly faster than a human being). The fact that you find the similar concussion rates between these two sports surprising is good reason for you to doubt your ability to identify dangerous sports based on your intuition for how violent they are.
Head to head collisions are relatively rare. You could play an entire career without getting one. Heading the ball isn't that bad, actually, and certainly doesn't happen often. Players can go through a season without ever doing it.
Either you don't watch much Football, or you don't watch much American Football. One only needs to watch a few games of each to see how violent they are. American Football has dozens of people smashing into each other (often head-first) every minute of the game.
Much more than other sports? No, I don't think so. Modern concussion tracking studies take baseline cognitive measurements and then periodically re-measure throughout the year, regardless of whether the player reports an injury.
Somebody ran a survey where they looked for replies that indicated "probable" concussions that were unreported, and they found
> The sports with the most unreported concussions were women’s soccer (24%), men’s football (21%), field hockey (13%), and cheerleading (10%).
I don't believe those numbers are normalized for the number of concussions, and in any case would indicate that women soccer players were slightly less likely than football players to report a concussion conditional on having one.
As for "unrecognized" concussions (i.e. the athlete gave a reply on the survey that sounded like maybe they had a concussion) they say
> The sports with highest potentially unrecognized concussions were football (55%), cheerleading (50%), and cross-country (28%).
which to me means you can't trust this survey at all. Whatever they're interpretting as an "unrecognized" concussion, it happens as often in cheerleading and over half as often in cross-country.
On the other hand, if you want a human interest piece, you can go read skierscott's link to the NYTimes blog post about how all those football players are toughing out brain damage....
Every time some one does a study they find they're under reported in every sport. They might be more underreported in football but its also under more scrutiny so its hard to say who knows how the reporting rates compare.
The thing you're missing is Chronic traumatic encephalopathy. The current theory is that CTE can be caused by the constant repeated non-concussive hits unique to football (at least among popular American sports), so analyzing concussion rate really isn't helpful.
>A brain injury study conducted at the Boston University School of Medicine showed that 33 of 34 players tested post-mortem showed clear signs of CTE.[1]
Even when you account for selection bias the number of NFL players with CTE is insane.
There is a lot of evidence mounting that CTE is a problem in soccer as well. Not from head to head collisions but as a sort of repetitive stress injury from heading the ball. Teams are starting to put players, especially at the youth level, on header counts during practice to mitigate this.
As I see it there are a variety of ways to become injured in sports:
- traumatic injury such as concussion, spinal injury, torn ligaments, broken bones, etc.
- repetitive stress injuries such as CTE, tendinitis, stress fractures, etc.
- what I'll call body stress injuries. Things like putting on too much weight for your frame to play lineman in football, extreme weight dropping for weight class sports, or the extreme oddities professional cyclists put themselves through for an advantage.
Nearly every sport you play has some chance of having injuries in at least one of these categories. The problem is that football has a high likely hood of injuries in all of these categories, and at the worst case of the injury in the category.
Ahh, good, yes CTE is at least a more interesting critique. However, I believe the non-concussive theory is purely a conjecture at this point. This is one of the authors of that Boston study:
"While it remains unknown what level of exposure to brain trauma is required to trigger CTE, there is no available evidence that occasional, isolated or well-managed concussions give rise to CTE," one of the study's co-authors, Dr. Robert Cantu, said in a press release.
So basically, you're just stuck with your priors on this one. As far as I am aware, CTE data doesn't provide you with any additional evidence for non-concussive effects beyond what you could have conjectured pre-CTE.
Of course, the media has breathlessly reported on how NFL players are all commiting CTE-induced suicide despite the fact that the NFL suicide rate is less than half the rate of the general population...
That quote doesn't say anything about non-concussive hits.
"there is no available evidence that occasional, isolated or well-managed concussions give rise to CTE,"
He said there was no evidence for occasional concussions, he didn't say anything about repeated non-concussive injuries.
Here's a quote from the BU CTE center
"We believe CTE is caused by repetitive brain trauma. This trauma includes both concussions that cause symptoms and subconcussive hits to the head that cause no symptoms." [1]
I'm a big guy and I live in the south, so you can bet I played my share of football growing up--there are definitely a lot more repeated hits to the head in football than any other popular youth sport.
The fact they're finding it in many other sports and in military personnel, as pointed out in the FAQ, makes me pretty skeptical that this is a disease strongly linked to nonconcussive hits since hockey players and soldiers aren't butting heads every day. But it's pretty hard to draw conclusions while the data and definitions are so vague. Do you know if they've looked specifically at populations of long-time football players with no concussions?
A review article from 2012 had this to say
> While it is clear that anyone who suffers repeated head trauma, regardless of the mechanism, may carry the risk of developing CTE, there is no clear consensus on how much or how little trauma is needed to cause CTE. While most feel CTE is a manifestation of repetitive trauma, the question still stands if it can be caused by a single TBI [10]. In a study by Johnson et al., widespread tau and beta-amyloid deposition was found in the brains of individuals who suffered a single traumatic brain injury. The study included the examination of postmortem brains from long-term survivors (1–47 years) of a single TBI () versus uninjured age-matched controls (). Results showed NFTs to be exceptionally rare in young uninjured controls, yet were abundant and diffuse in one-third of TBI cases.
The last sentence seems to support the idea that the appearance of symptoms is an important threshold, but it's hard to tell what they mean; could also be that anyone cracking heads enough to get sub-concussive CTE are likely to have picked up at least one full concussion.
> I'm a big guy and I live in the south, so you can bet I played my share of football growing up--there are definitely a lot more repeated hits to the head in football than any other popular youth sport
I played 11 years of football, mostly on defense and mostly with my head, and I fully agree. I coach youth football, so any data that would show a dramatically higher risk for football than other sports (which are generally regarded as acceptably risky) is of great interest to me.
Or Hockey or Soccer? Concussions are common in many sports, soccer which is considered a "safe" alternative to football has the second highest rate. Also not unlikely to occur in Basketball or Baseball.
The biggest thing for me is the aim of the sport. The aim of American football is to stop the opposing team using your body; soccer and hockey both involve pretty intense strategy to get the ball/puck in the net.
Hockey does have some body-body impact (through checks). I haven't played much hockey, so I don't know how severe it is.
I think the general overemphasis on sports in this country (are other countries as bad?) is ridiculous. Resulting in things like parents getting into fights over it. And parents ignoring doctors recommendations to pull the child out because of a concussion ("But they need to get back in the game!" "My son is no quitter!"). Its just insane. Is it really that important that you be the best at throwing a fucking ball around?
Me personally, I'd rather be the best at creating something.
The extreme specialization is bad for the bodies, too. When players are in specific positions, you basically sacrifice other parts of your health in order to be as good as possible at, say, running into another human.
Other people point out how 1 group seems to separate into 3. That 1 group had to be good at lots of different things, and while football was probably still a rough sport, there was no chasing of extremes.
I noticed this with the NHL. Players are way more fit resulting in a faster game with more brutal body-checking. That compounded with improved protective equipment has allowed players to have a lot less regard for others safety.
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.
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.
The group on the far left would be the defensive backs actually. That position is best suited for the little and quick guys. While receivers can, and are small (think a Wes Welker type), receivers are also enormous (Calvin Johnson). If a corner were the size of Johnson, for example, the team would put him in as a receiver since that's more valuable.
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.
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.
The middle group as mentioned is a mix of linebackers, tight-ends and also running backs.
> That middle ground is probably not best suited for any role
Modern NFL is very specialized. You have linebackers of various sizes who are used in situational conditions (passing vs running downs), and also vary in size/height based on the defensive scheme. e.g. A linebacker in a Cover-2 based defense is probably lighter/faster vs a larger linebacker used in a 3-4 defense.
William "The Fridge" Perry was probably the inspiration for the absolutely huge linesmen of today. That separation started a little bit after his seasons with The Bears.
Probably not as much as you think, because he really wasn't that good of a football player and made his name as a situational fullback. The Cowboys offensive lines of the early 90s are probably the blueprint for the current NFL offensive lines. Those guys were freaking enormous compared to the average line, and it's the main reason why Emmitt Smith is a household name.
The Cowboys themselves were modeled after the Hogs and Giants offensive lines of the 80's. The competing archtype in the late 80's early 90's was the lighter, more agile offensive lines of the 49ers.
I'd agree with that. The 49ers of that era were able to benefit from a lack of a salary cap. They were stacked across the board. It was the place you went when you were an aging star who wanted to win a ring. They wanted those more nimble guys because of the crazy pass rush of the other teams in their division and conference.
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...
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.
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.
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.
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.
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.
> 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...
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.
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?
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:
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.
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.
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.
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.
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.
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.
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.
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.
"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