Monday, November 17, 2014

Team Ratings, Rankings, and Seedings

In most of the world, table tennis is a club sport and a team sport. The two go together, as club members form teams and play against teams from other clubs. The team aspect is not that strong in the US . . . yet. But it grows slowly every year. To me, club team activity is one of the measures we can use to judge the success of the sport in our country.

We have entered the season for team competition. College teams in the NCTTA League have been competing since the first divisional meet in October, and will continue fall seasonal play through this weekend. They'll pick up again in January and February to complete the regular season, followed by regional qualifiers and then the Championships in April.

For those of us who don't have the opportunity to play in a team league, the next best thing is a team tournament, and you have three team tournaments to choose from this Thanksgiving weekend. Personally, i consider team competition to be much more fun than individual tournaments, and i strongly encourage everyone to enter one of these tournaments.

Butterfly Thanksgiving Team Championships - Hobart, IN (Chicago Area)

North American Teams - National Harbor, MD (Washington DC Area)

West Coast Thanksgiving Teams Open - Fremont, CA (San Francisco Bay Area)

But i digress. This post was supposed to be about ratings, rankings, and seedings.

Tournament players generally understand individual ratings and rankings. A player rated 1900 has demonstrated better match results than a player rated 1800. Therefore if we were to rank the players, the player ranked 1900 would be #1, and the player ranked 1800 would be ranked #2. Rankings are the numerical order of the players involved.

Seedings are similar to rankings. Rank is the order, and seed is where they will go in the draw. It is a subtle difference, and most people don't need to worry about the difference. Basically, the player ranked #1 will be seeded #1 and have the "best" draw; the player ranked #2 will be seeded #2.

How about doubles? We don't play a lot of doubles in the US, and we don't have many established doubles pairs who always play together. If we did, we would be able to use the doubles match history of those specific pairs to establish a national doubles ranking order. But since we don't, we are left with using singles ratings to determine doubles rankings. It's not ideal, but we get by - we add the individual ratings of each doubles pair together to establish a "doubles rating", and use that to rank pairs.

Team competition is quite a different story. Again, we don't have many established teams that always play together. So looking at what we do with doubles, the obvious practice would be to take the sum of ratings to find a "team rating".

This is quite easy to do, but unfortunately a numerical sum is not a very good reflection of actual team strength.

Take these two fictional teams. They'll play in the old Swaythling Cup format: 3 players per team, playing the best 5 out of 9 matches. The teams are composed of players with the following ratings:

  • Team #1: 2400, 1800, 1800
  • Team #2: 2000, 2000, 2000

If you use the concept of a "team rating", these two particular teams will be tied at 6000, which would mean that they are equal in strength. But if you play out the team contest, team #2 will win by a score of 5-3 almost every time. They will almost always lose 3 matches to the 2400 player, and almost always win 5 matches over the 1800 players. The reality is, team #2 is clearly stronger than team #1, and in many situations, using the sum of individual player ratings will not give good seedings.

A better alternative can be found by looking at how the ITTF ranks teams. You can read about their ranking methodology on the ITTF web site. In summary, they take every national team in the world, and run a simulated giant round robin between all teams. The simulation assumes that a higher ranked player will always beat a lower ranked player. Each team is then ranked according to the results of the simulation, as if the teams had actually played out a giant round robin.

Using this method of ranking gives superior results when seeding teams. A weak team sometimes brings in one particularly strong player to try to pump up the team's seeding, and if seeding is based simply on the sum of individual ratings, the effect of that strong player will be exaggerated. These issues and others are solved when seeding is performed by simulation.

Here's an example of team seeding from this year's America's Team Championship, an annual event held over Memorial Day Weekend in Rockford, IL:

These were the teams seeded into the fourth division. If the sum of player ratings had been used, the TriniAmericans would have been seeded #24 - higher than all of these teams, and actually into the next higher division. But when the matches are played out, they should fall into the middle of the pack in this division. On the other side, the Fab Four's total rating is not especially high, but against this field they are likely to win most of the contests, albeit by scores of 5-4 and 5-3.

If you play in a team tournament that i'm directing or refereeing, it will probably seed teams using this method of seeding. I've been using it for several years, and would recommend that other team tournaments adopt it.

Since we're relying on a computer simulation to rank teams, conceivably we could go one step further and consider the win probability for each individual match. For example a 2400 player has an almost 100% chance of winning against a 2000 player, and it's reasonable to assume he'll give his team one point for that match. But when someone rated 1830 plays an opponent rated 1825, the match is almost a tossup. In the simulation, the 1830 player could be awarded 0.51 points, and the 1825 player could get 0.49 points to reflect how close the match is. It's not exactly simple to do this in a spreadsheet, but it's not terribly difficult either. You just need to figure out each player's chance of winning and go from there.

Normally i don't seed teams using win probability, because it's more difficult for players to follow. However this method results in even better seeding, and in the NCTTA League we will use this method to seed teams at the College Table Tennis Championships. If you're curious, you can read more about this method on the NCTTA web site.

Not table tennis.

I don't live in New York and have yet to see the Top Spin documentary film. But i did see a lovely movie about musicians entitled "Begin Again". If you're a sentimental sap like me, maybe you'll enjoy it. 

In Memoriam.

My friend Jock Oubichon moved on last weekend, at the young age of 47. He may not have been well known in the world of table tennis, as he didn't travel much and didn't draw attention to himself, but he made a mark on everyone who knew him. He was a person who had willed himself to become a positive force - an intense yet gentle person who really loved helping people. As a table tennis player and coach, he had a great eye for human mechanics, and he loved coaching though i don't know if he ever charged anyone for his help. Several years ago i had the honor of nominating him as USATT Volunteer Coach of the Year, and if i recall correctly the USOC named him a finalist among all sports.

I didn't see much of him in recent years due to geography, but i always looked forward to meeting him at the Nationals in Las Vegas - me working at the tournament, him meeting with the sponsors of his club's junior program. I will miss him.

Ron Spencer's message about him can be read at the San Diego TTA's web site.

Friday, August 1, 2014

Which Ball Should I Buy?

Players have been asking this question, one that i find a little surprising: Which table tennis ball should we be practicing with?

To me, the answer seems very simple, and i can't imagine it ever being different: Practice with whichever ball will be used at the tournament you are preparing for.

It seems so obvious, yet i often see players - including very good players - practicing with a ball that is different from the one that will be used at the competition. Even during the day of competition, i see players warming up with an orange ball when the tournament ball is white. In my opinion, this is poor preparation.

It might be a hassle to get the precise ball that will be used at the tournament, but you should be able to come close. At least use a ball that's the same color, made in the same country, of the same construction, and now, made of the same material.

(Ideally, you should be training in conditions as similar as possible - same type of table, similar flooring, time of day, altitude, etc. Some of these are hard to achieve, but getting the same type of ball shouldn't be that difficult.)

Tournament directors in domestic competitions have always been required to state the brand and color of the ball that will be used. Now they are also asked to clearly state whether it will be a celluloid or non-celluloid ball. But if you're not sure which ball your upcoming tournament will be using, you need to ask them.

If you play internationally, the ball that will be used is pretty much predetermined:
  • ITTF Junior Circuit events prior to the Youth Olympic Games - Butterfly *** celluloid, usually white
  • Youth Olympic Games - DHS *** celluloid, probably white
  • ITTF Junior Circuit events after the Youth Olympic Games - Butterfly 40+ *** non-celluloid, white
  • ITTF World Tour events - DHS 40+ *** non-celluloid, white
  • North American Championships - Double Fish 40+ *** non-celluloid, white
  • World Championships - Butterfly 40+ *** non-celluloid, almost certainly white

What about US tournaments?

Tournament directors can choose any approved ball as their tournament ball, and both celluloid and non-celluloid balls are approved. In theory they could even use ball X for some events and ball Y for other events. I cannot predict which ball a particular tournament director will choose, but put yourself in their shoes: If you were a tournament director, and you wanted to maximize player attendance, which would you choose?

At the moment, most US players are still using celluloid at their clubs, and it would be somewhat risky for a local tournament director to host a tournament tomorrow using non-celluloid balls. Non-celluloid balls are not sold by all major brands yet, and bulk cheap non-celluloid practice balls are even harder to find. Things will probably change as the availability of non-celluloid balls improves.

One more question that people ask: Should i buy balls from auction sites or department stores? To that i respond: If you were a ball manufacturer that produced several different grades of balls, where would you send your best ones - to the person running online auctions, to the department store, or to the specialist table tennis store?

Friday, July 4, 2014

Possibly a Record Setter

A minor record may have been broken this Independence Day in Grand Rapids. Check out the start of this match between Riyo Nemoto (WR 110) vs Eriko Kitaoka (unranked), both from Japan, in the 2014 US Open Women's Singles quarterfinals:

The rules require the expedite system to kick in after 10 minutes have passed in a game, if 18 total points have not been played. Therefore a point shouldn't last more than 10 minutes. The exceptions would be if the game has already reached the 19th point and then suddenly the players decide to play a marathon point, or if the umpires are not doing their job of timing the match.

In this case, the first point of the match started when Nemoto tossed the ball at 15:47 of the video, and the point was over at 25:44; so the point lasted 9 minutes and 57 seconds. If they had continued for four more rallies or so, the assistant umpire would have called "time" and stopped play, thereby cancelling the point; they would have started again at 0-0. But Nemoto pushed into the net, the players received a loud ovation and each took a well deserved stretch, and the assistant umpire called "time" almost immediately which started expedite at 1-0. So is 9 minutes, 57 seconds the longest single point in ITTF competition since the sport changed to a 10 minute time limit?

(Expedite used to be called at the 15 minute mark, back when games were played to 21. Personally, I enjoy watching expedite matches.)

A few minutes after this singles match, Kitaoka and Nemoto turned right around and played a doubles match as partners; they won that match and have made it into the semifinals.

The US Open concludes tomorrow. The first Women's Singles semifinal is scheduled to take place at 3:45pm Eastern time and will feature the winner of this marathon match (Nemoto) against another chopper, top seed Li Xue of France. Follow the action here.

Tuesday, June 10, 2014

Tokyo Recap, Part Two

Larry Thoman, general manager at Newgy and longtime USATT contributor, asked a question: why were most of the divisions at the World Championships played as single elimination during the second stage, instead of the traditional progressive knockout?

In the minutes of the September 2012 meeting of the ITTF Executive Committee, you can find the following notes:

5.6 2014 WTTC update and playing system:

* The proposal to reduce the number of matches particularly in the top 2 divisions would allow a better schedule and prevent the event growing further.
* Eliminating all position matches, including for 13 and 14, would assist with positions 3 and 4, 5 to 8, 9 to 12, 13 and 14 being shared.
* The proposal to the Board of Directors should specify that if approved, the playing system would be implemented in 2014.
* Following the site visit and advice received, the organisers proposed various changes:
    - Fewer courts in the 1st gymnasium.
    - No courts in the swimming pool.
    - Adding the Metropolitan Gymnasium to replace the National Olympic Memorial Youth Centre.
    - Replacing the Keio Plaza Hotel and other hotels by the Prince Hotel which would improve transport logistics as all participants would stay here.
    - All meals could be served in the Prince Hotel although lunch may need to be provided at the venue due to possible time constraints.

Now that the event is over, it appears that the modified playing system was approved - as evidenced by the lack of courts in the swimming pool!

Deliberations at the 2014 AGM
The 2013 and 2014 Worlds both had record numbers of entries. Both tournaments required the use of two separate competition facilities. The complexity of the tournament has been a problem for a long time and it continues to grow - now it takes place every year instead of every two years; more players enter every year with larger entourages; the hospitality demands increase; there is more media. Growing pains are generally a good thing . . . as long as the "pain" part is dealt with. The difficulties include increased costs, higher staff demands, and greater host requirements which lead to fewer sites being capable of hosting the event. (See also: how many cities are bidding to host the Winter Olympics.) A more difficult event also means there are more potential points of failure, and more potential difficulties for the players. For example, the added complexity of requiring two playing halls is quite significant.

It is in almost everyone's best interests to reduce the complexity of the event. In my opinion, removing many of the final positional matches at the Worlds helped accomplish that.

But that's not enough. For the 2017 Worlds, the ITTF received only one bid. What would have happened if that one country had not submitted a bid? It seems that changes need to be made to reduce the host demands at each World Championships.

So at the latest Board of Directors meeting (which i did not attend), they voted to reduce the number of player entries to the Worlds. The number of entries per country continues to be based on the number of top ranked players from that country. Basically:

  • Most countries can enter 5 singles players (per gender)
  • Countries with a player ranked in the top 20 can enter 6 players
  • Countries with two players in the top 20 can enter 7 players
  • The host country can enter 7 players

  • Most countries can enter 3 singles players (per gender)
  • Countries with a player ranked in the top 100 can enter 4 players
  • Countries with a player ranked in the top 100 and another player ranked in the top 20 can enter 5 players
  • The host country can enter 6 players

I estimate that this will reduce the total number of entrants by 10%-15%. But the number of participating countries increases every year, so 10% may be closer to the mark. If i understand correctly, the Executive Committee would like to further reduce the number of entrants in 2017, but that change has not been proposed or passed and nobody knows what will happen. I suspect the general sentiment is that reducing the number of participants is a negative, but we want the World Championships to exist and continue to be a great event, and we want it to be a practical event for more cities.

A hundred world class players and coaches, packed like sardines prior to match time

People who care enough to pay attention to the actions of the ITTF knew that this change was intended to keep the tournament manageable. It's clear from the minutes of several EC meetings that they had been considering different ways to reduce the number of entrants, and accepting proposals from multiple organizations and associations on the best way to do it. In the end this reduction was proposed and passed with 70% in favor.

And then there are those who don't pay attention, and write articles like this: ITTF introduces changes to World Championship in bid to reduce Chinese domination.

"In what comes across a further attempt to reduce the Chinese monopoly on the medals table, the Board have also reduced the numbers of players per association available to play in the Championships."


When i first read this line - that the reduction of players is designed to restrict China - i saw it as the typical haters repeating their "blame the ITTF" mantra. But then someone else made the same claim on another forum or blog. And then another.

What is going on?

Can any of the people making this claim cite a reference from the ITTF indicating that the intent of this change is to attack the Chinese team?

Can any of them describe how this change would actually decrease the Chinese players' chances of winning?

Then i heard some claims that the adoption of non-celluloid balls is also an attempt to disrupt Chinese dominance. And the change to 40mm balls. And the switch to 11 point games. Are these people for real?

Here's the reality:

The number of players permitted to enter the World Championships in 2015 will probably be reduced. The intent has nothing to do with China or any other particular country; the purpose is to limit the number of entries and reduce the burden on the host country. The change will have no effect on the performance of the Chinese players.

The number of teams permitted to enter the World Championships in 2016 will be limited to 96 men's teams and 96 women's teams. Again, the intent has nothing to do with China or any other particular country. Reducing the number of teams will reduce the burden on the host country. The change will have no effect on the performance of the Chinese team. (But it will affect the US Men's team; if we're not careful, it is possible that we will lose our eligibility for the Worlds. These changes affect the small countries more than the large ones.)

The adoption of a non-celluloid ball, 40mm ball, or 11 point games had nothing to do with Chinese players or any other particular country.

Personally i'm not satisfied with the way teams will be allocated for the Worlds, or with the language that describes the allocation. But i suspect we'll survive.

The minutes of the ITTF AGM, Board of Directors, and Executive Committee meetings are all public. If you want to understand things, read them yourself. Secondhand reports don't seem to be very reliable at the moment. But i'll attempt to put some weight back on the reality side of things, and describe some other changes that were adopted at this Worlds:

In one of many briefings, umpires are instructed to smile
* Players can now select a match ball. Well, they could kind of select one before, but it's clearer now. In the past, players could select up to three match balls, and one of the selected balls would be randomly chosen for the match. So the players could select three equally good balls and one would be used; or they could select one superior ball and that one would be used, but if it broke they would be stuck with a backup ball that had not been selected. Now, players can do both - select three match balls, and the particular one which will be used first. Not a major change, but one that will reduce a lot of behind-the-scenes aggravation.

* In a return, the ball doesn't need to cross the net. In the past, a return was: strike the ball, cross the net, hit the opponent's side of the table. Now, it will be: strike the ball, hit the opponent's side of the table. The net becomes a defined obstacle, but no more (except for net serves). This is a subtle difference that i hope will have no real effect on match play.

* There is now an ITTF Technical Leaflet for net gauges, written by Nobuyuki Shirakawa (JPN). Many net gauges are used throughout a competition, but there was no formal standard for them until now. Whether there will be ITTF approval of net gauges remains to be seen.

* Changes were made to the Technical Leaflet for balls, maintained by Torsten Kuneth (GER). One of the major changes is that balls approved in the future must have "Made in (country)" on both the ball and the packaging. There was also some relaxation of ball manufacturing tolerances for a year and a half, as production continues to be refined.

* Changes were made to the Technical Leaflet for racket coverings, maintained by me. Most of the changes were clarifications of past issues:
- In the past, the TL stated that a thick non-wood coating on a blade was not permitted, however penhold players often used paint or a paint sheet on their racket which was technically in violation of this restriction. So an exception was made for this specific purpose.
- It has always been implicit that the red side of a racket should be uniformly red; printing on the sponge or blade, or dark wood grain lines, should not show through such that the color is not uniform. But this was often questioned, so this requirement was made explicit.
- The pimple friction requirement was clarified. The laboratory test is unchanged, and no rubbers have had authorization rescinded because of it, but the language was simply made more generic.

* Another thing that we should see in the next issue of the List of Authorized Racket Coverings is a back page which lists all of the rubbers that will be leaving the LARC. This will be useful for players so they can quickly see if the rubber they use is being withdrawn, and for umpires so they don't have to carry around two lists.

* The ITTF now has 220 member associations, tying it for first place with volleyball. In the simplest terms, this means more people are playing table tennis.

* A resolution was passed to encourage study of multicolored balls, which would make spin more visible, especially on instant replay. This doesn't change anything yet because the rules still specify white or orange balls, but perhaps a change will come in the future.

The 2015 World Championships will be held in Suzhou, China. I'm not sure if i will be there. But i am reasonably sure that any changes that are decided there will not be based on sudden impulses. The ITTF is a large and conservative organization; it takes a lot of work to make something happen. The work takes place over the course of the year, and what materializes (or fails) at the Worlds represents only a tiny bit of the labor that led up to it.

Saturday, May 17, 2014

Tokyo Recap, Part One

One country, one apple
You've already read the headlines out of the Zen-Noh 2014 World Team Table Tennis Championships, and i'm not planning to repeat them; it's not that kind of recap. This one is a little more first-person.

I go to a lot of tournaments, but not as a spectator. Occasionally people ask me to be their match coach at a local tournament, but besides those instances, it's been many years since i've gone to a tournament where i'm not an official.

So i was in an unfamiliar situation, in that i could cheer for particular players - Team USA in this case.

At this Worlds i had a couple meetings each day in Yoyogi National Gymnasium, and therefore i was able to watch several of US Women's Team's contests against their first division opponents. Meanwhile, i had no opportunity to watch as the Men battled through and went undefeated in their group at Tokyo Metropolitan Gymnasium.

Though i haven't had the chance to watch much of it, the video coverage at this Worlds was the most extensive ever. In the main hall, first division matches were broadcast simultaneously from two tables on ITTV and one table on TV Tokyo. Then in the second hall, the remaining divisions had three matches simultaneously broadcast on YouTube. In addition i'm told that the remaining six courts in the main hall were recorded by the ITTF, though i don't know where that video will surface.

The second hall looked kind of like a US tournament
The US Men (Timothy Wang, Adam Hugh, Jim Butler, Yahao Zhang, and Kanak Jha) had a tough elimination draw. They needed to reach the finals in order to get a guaranteed promotion to second division in 2016. When i saw the draw i had guarded hope, as our first opponent (after a bye) would seem to be Lithuania, who had defeated us in 2012. We would need to beat them as well as one more team to reach the final. But Kanak said that the team had identified Saudi Arabia as a strong and a more likely opponent, and they was right. So despite being the top seeds in the division and going undefeated in group play, the US was drawn in a half which included #2 Switzerland, #4 Lithuania, the strong team from Saudi Arabia (who beat Lithuania before knocking us out 3-2), and eventual division winners Puerto Rico. I don't think it was possible to get a tougher draw.

To my eyes, the loss to Saudi Arabia was largely because the Saudi ace was on fire that day. Nevertheless, the Men fought to the end, and you can see their final contest against Saudi Arabia on YouTube.

There are no easy groups in first division and the US Women (Lily Zhang, Prachi Jha, Crystal Wang, Erica Wu, and Angela Guan), seeded fifth in their group, were up for the challenge. Their first contest of the tournament against Hungary was perhaps their biggest opportunity for an upset, but nerves were a factor and it was a tough loss for us as Prachi was up 9-6 in the fifth game of the final match.

The second contest was a 3-0 loss to host and eventual finalist Japan. It's one thing to be playing on center court in a noisy arena; it's another to be playing on court one when the cheering is targeted directly at the court you're playing on. The ladies handled it well and i think they enjoyed it, despite losing 3-0. I wasn't able to watch these matches live, but saw some on TV. The Japanese commentators seemed to relish calling Lily Zhang, "Lily-chan".

Sizable groups of fans were in attendance from day one, and i say "groups" because there were two distinct contingents. The Japanese fans obviously had a lot to cheer about, but there was also a large crowd of North Korean fans, presumably Koreans living in Japan. Both groups were kept in sync with their own cheerleaders, and it was sometimes jarring to hear the clash of applause when North Korea and Japan were both playing, on different tables. Seiya Kishikawa seemed to have a hard time playing while the Korean fans were singing a tune, over the course of several points during his match against Kalinikos Kreanga.
The US Women got on the board after the next contest, a 3-0 win over Australia. The following matchup against Belarus looked to be a tough one, and chopper/coach's pick Angela Guan worked hard to help prepare her teammates for the upcoming challenge. One expert told me that Crystal was our strongest player against chop, but i have long believed that Lily ought to beat almost any female chopper, given proper instruction and guidance. Even so, given her past results, i didn't expect her best career win to come against world #11 Viktoria Pavlovich. Unfortunately we were short of the upset again, as Prachi lost in the fifth against Alexandra Privalova. And though Crystal got the desired matchup against chopper Elena Dubkova (who sported a much improved attack), she also couldn't win in the fifth game.

In the knockout stage the US Women seemed to have a decent draw - not especially lucky, but not bad. The immediate goal was to reach the semis, guaranteeing first division placement in 2016; that would require a win against Serbia and then against the Czech Republic. I fully thought we could beat Serbia 3-0, but it was not to be. Crystal might beat Ana-Maria Erdelji the next time they play, but this was Crystal's first time ever playing against a short pip chopper, and the spin variation off Erdelji's racket was noticeably different from long pips. The ladies had their chances, but the Serbian girls played tough. A variety of the US Women's contests can be seen on YouTube and ITTV.

The 1983 Worlds were also held in Tokyo, also in Yoyogi National Gymnasium. History repeated itself this year in the women's competition, as the host Japanese team came in second place against China. For the third time in a row, the men's runner-up team was Germany, behind China. Back in the day, the Swedish men placed second three times in a row (1983, 1985, 1987) before they won in 1989.

Unlike in 1983, and every other year until 2013, the competition was held in two different facilities. Running a team competition in two halls wasn't a huge problem for the players, as most teams played every match in either one hall or the other. But it was an additional burden for the organizers, and for coaches, captains, and spectators who would have to go back and forth between gyms.

Almost all vendor booths and concessions were outdoors
Whatever the hardship, things were always smoothed over by the superb hospitality. Long one of the most modern cities in the world, the reliance on manpower in Tokyo was noticeably higher than we normally see in the US. Everywhere you went, members of the tournament staff were stationed along the way to bow, smile, and greet every single person. Information desks were constantly manned at the hotel and the playing venues. Not only were the staff numbers high, they were all diligent and well-organized. Volunteers joking around on break were hard to find.

Table tennis is one of Japan's two national sports and their love of the sport is evident in the media (numerous print media sources and constant TV coverage), the event support (over a thousand staff members), and the general care put into the event and its attendees. The week of the tournament was scheduled to coincide with four federal holidays: Shōwa Day, Constitution Memorial Day, Greenery Day, and Children's Day. Also in the middle was the observed but not official May Day holiday.

May Day in Tokyo
The 6.0 earthquake on the final day was the opposite of a holiday, but provided an additional dose of excitement for both residents and visitors.

As i said before, i was not an official at this tournament. But i wasn't there just to hang out either. The World Championships is the most convenient event for table tennis people around the world to meet, because many of them will be going there anyway. President Adham Sharara said he had 87 meetings at these Championships. My meetings were much fewer in number, and only about equipment or our association. The non-celluloid ball was a hot topic of course, but the ball is not my area of focus; here are a couple of things i brought:
Prototype flatness gauge with movable feet to adjust to each racket

Why would you strap three balls together and rest them on a racket?

2014 is not a major election year for the ITTF, but a new Athletes' Commission was elected. Vladimir Samsonov, the consummate gentleman, was re-elected as chair of the commission. The proposal to have an athlete position on the Executive Committee failed by a narrow margin in the AGM. I'm told that a major reason for failure was due to a misunderstanding of the proposal. Perhaps it will come up again next year.

More details about the events at these Worlds will come in another entry.

Sunday, March 23, 2014

The Impact of College Table Tennis

Here are a few points which i believe are obvious and true:

1. Table tennis is a great sport and we want it to grow.
I can't truly speak for what anyone else really wants; i'm not a mind reader. But i'm going to assume that local players would prefer not to have to travel to find competition. I know that i'm constantly working with people who, like myself, spend thousands of unpaid hours every year to try to make things better. And i suspect that when people such as our top players, their families, and others donate to the USATT's Annual Giving Campaign, it is with similar intentions. I assume most people want things to grow.

2. Though many people in the US have played table tennis, it is not a major professional sport in the US.
I recall a story told by a friend about his degree in sports management. He had planned to write his thesis about a subject related to table tennis, and his faculty advisor suggested that for a "sports management" degree his thesis should be about a "sport", not table tennis.

It's one thing if a random person doesn't consider table tennis to be a sport; it's another when a person working in sports has this view. This is what we're up against.

3. The most successful table tennis countries have one of the following: (a) a cultural connection with the sport, (b) significant government funding of table tennis, or (c) strong and deep table tennis leagues.
I don't think we can count on (a) or (b) ever happening here. Not every strong table tennis country is well funded by its government, yet somehow they get by. Maybe they just have good organization, strong clubs, and a wealth of volunteers.

4. In the US, professional sports often have some connection to college sports.
It varies by sport, but professional athletes in many sports go to college first, and i get the feeling that college sports are more important in the US than they are in other countries. On the other hand, sport clubs seem less important in the US than in Europe.

Yeah this is rambling a bit, but it leads to this one:

5. College leagues and their associated scholarships drive junior participation in other sports.
How much money do your neighbors spend on their kids' participation in football or hockey or whichever sport they play - not with the goal of having them become pro, but rather so they can get a scholarship? Sometimes they spend more money in development than the resulting scholarship is worth.

Why can't this work for us?

Right now we have a nice group of juniors who play for a variety of good reasons: it's fun, healthy, and character building. It's a sport that can be played over your whole life. Some players aspire to be World Champions or Olympians. Another possible future is to become a professional table tennis league player, but i'm not sure how many are thinking in that direction.

These are not bad reasons to play, but they aren't motivators that reach a lot of people. Only a few people go to the Olympics and it's only once every four years. Our group of juniors wouldn't compare to the number of soccer players in a city school district. What if there were an additional motivation: The opportunity to earn a table tennis scholarship to a top university - one of thousands of such scholarships? How many young players would there be? How many collegiate and junior coaching jobs would be created to support these programs? How many adults would come out of those college programs with a desire to continue playing in adult leagues? How many of those adults would be willing to support a professional league?

If we had a complete system of college table tennis, the sport would be transformed at all levels.

We're still far from that, but even so, college table tennis has come a long way. 167 coed and 43 women's teams participated in the 2013-2014 NCTTA league - the highest numbers to date. A couple schools have varsity programs and scholarships, while many others have programs that are well-established as club sports, with funding for a little travel and some with part-time paid administrators. There are even players who moved to the US so they could play table tennis (and go to school). I think college table tennis has made an impact, but at the moment it doesn't transform the sport like it could.

To reach a new level, in which table tennis scholarships really have an impact, a lot of work needs to be done. At this stage, growth still needs to be pushed; it doesn't happen spontaneously. Many people think that some nebulous group known as "they" need to develop programs for players; instead of players, parents, and coaches doing it themselves. Unfortunately the small pool of table tennis volunteers is often working at capacity already. For every program that exists, somebody had to step up and make things happen. For every NCTTA club - as well as every USATT club - there is at least one leader. This is not going to change. An optimist will observe that this means we have over 200 table tennis leaders in our colleges. The pessimist will point out that for the sport to double in size, we need twice as many leaders.

We're always looking for more help. Any volunteers?

How about one final point?

6. Growth of table tennis in the US would bring value to the sport in other countries.
The US has a unique influence on world culture, and if table tennis became more popular in the US, it would have a worldwide impact on the sport. I believe the ITTF recognizes this and would love for the sport to be huge in the US. And i believe the ITTF sees value in college table tennis in particular because their marketing partner, TMS International, is the title sponsor of this year's NCTTA Championships.

The TMS 2014 College Table Tennis Championships is the finale of the 2013-2014 NCTTA league, to take place April 4th through 6th in Monroeville, Pennsylvania, a suburb of Pittsburgh. The action will be streamed live all weekend on the ITTF's YouTube channel, and will feature three US Singles Champions among a field that's deep as always. Don't miss it!

Tuesday, February 25, 2014

A Lesson in Simple Mechanics

Before we start with today's lesson, here's a pop quiz. Which of these balls are not like the others?

The answer is in the photo further down the page. Skip down to it if you wish, but you are also welcome to continue reading first.

Today's lesson is about speed and spin in table tennis.

We don't measure speed correctly. In attempts to promote the sport, people sometimes cite numbers which attempt to illustrate the challenges involved in playing table tennis, and one of those numbers is the speed of the ball. Where does table tennis rank in a list of the fastest sports, or the fastest racket sports? How fast does a table tennis ball actually travel? 100 miles per hour is a high number cited; 60 mph might be more reasonable.

I believe that giving an answer in miles per hour is inadequate or counterproductive. Table tennis is clearly one of the fastest sports, and this is clear not by looking at ball velocity, but by looking at time: how much time a player has between shots, or how many shots are completed per second. A tennis ball has a higher velocity than a table tennis ball, but in table tennis there is less time between shots. It's the short amount of time that puts stress on the player, not the high velocity of the ball. Table tennis has far more shots per second than tennis, racquetball, or squash; and by that measure table tennis is the faster sport.

Similarly, we don't measure spin correctly. People cite spins in the range of 9,000 rpm (revolutions per minute), but how does rpm affect the player?

Spin is a little more complex than speed. Let's look at the primary ways that spin affects a player:
  • The spin causes the ball to curve; more spin causes the ball to curve more.
  • The spin kicks off the opponent's racket; more spin causes the ball to bounce off the racket more sharply.
In both cases, using rpm to describe spin is inadequate. If you compare a 40mm ball spinning at 9000 rpm with an 80mm ball spinning at 9000 rpm (all else being equal), they will behave very differently. The equator of the 80mm ball is traveling twice as fast as on the 40mm ball, and will jump off a racket twice as hard. It will also have a sharper curve through the air. It's common to use rpm as a measure of spin, but when we consider the effect of spin on a player, what really matters is the linear velocity of the equator of the spinning ball.

Why do we care?

Back in the year 2000, we switched from 38mm balls to 40mm balls. It was a widely circulated fact that the new 40mm ball would have less spin - but only if you were looking at revolutions per minute!

In fact, 40mm balls are not less spinny than 38mm balls in the measure that matters - the linear velocity of the equator. When a player strokes the ball, the tangential energy of the racket is transferred into the ball's spin. The linear velocity of the ball's equator is the same regardless of its size; all that matters is the stroke. No matter the size of the ball (but again, all else being equal), if a player applies 20 mph of tangential speed, the ball's equator will spin at 20 mph, and the ball will kick off the opponent's grippy racket accordingly. So if your goal is to make the ball jump off your opponent's racket, the size of the ball is irrelevant.

The other factor, the curve of the ball through the air, is more complicated. I don't want to get into it too much here; look up equations for the lift vortex of a spinning ball if you want details. But the conclusion is that for a given linear velocity of the equator, a larger ball will curve through the air more than a smaller one. That is, with a larger ball, the effect of spin is more pronounced than with a smaller ball for a given stroke, all else being equal. Intuitively this can be expected because the larger ball has more air resistance.

Didn't read all that? Here's the summary:
  • Table tennis is a fast sport when measured in time, not velocity. Forget about miles per hour and talk about shots per second.
  • For a given stroke, the effect of spin on the ball's bounce off the opponent's racket is the same regardless of ball size.
  • For a given stroke, a larger ball curves more than a smaller ball.

Now for the quiz results.

Another tournament, another surprise. This time it was the TMS Midwest Regional Tournament in the NCTTA College Table Tennis League, hosted at Northwestern University. Instead of bringing the MiniRAE device to test rackets, this time I brought a variety pack of balls.

The correct answer is: The three on the left are non-celluloid, and the two on the right are 38mm. (This was a pretty easy quiz because I arranged the balls this way rather than mixing them up.)

Now, if you forward this article to your friends and say "read this article about the new ball!" you'll spoil the quiz for them. I hope you don't.

As you may know, earlier this month the ITTF approved three non-celluloid plastic balls, made by DHS, Double Fish, and XuShaofa. All three are made in China. The DHS and Double Fish balls are of the seamed variety, similar to the celluloid balls that we use. The XuShaofa ball is seamless, and this fact can be seen in the photos.

Another thing you can see in the photos is the size of the balls. If you believe the rumors on the internet, table tennis after July will be an unrecognizable sport because of how different the poly ball is compared to the celluloid ball, not just in material but in size. Now look at the photos and compare the size of the poly balls with the celluloid balls, and the size of the 40mm celluloid balls with the 38mm balls. Is there a huge difference in size?

There's also a rumor on the internet that my wife owns a patent on table tennis balls. How likely is that? (Hint: I'm not married.)

I only have one of each ball. I measured the diameters and they came out to: 40.03mm, 40.15mm, 40.17mm. The rules specify that the ball shall have a diameter of 40mm, so yes, these balls meet that requirement.

From what I understand, the process of making these balls and getting them approved was not easy. The initial balls submitted to the ITTF did not meet all the required standards, and the manufacturers had to adjust their formulations multiple times. As I had stated before, anyone who played with a prototype ball, and delivered a judgment of "the new poly ball" based on their experience with that ball, will not know what an ITTF approved poly ball plays like until they actually have an opportunity to use one of the new, approved balls. I have a few prototype XuShaofa seamless balls, and they play differently from the ITTF approved XuShaofa seamless ball.

Back to the tournament. I wanted players to perform a blind test on these balls, to see if they could detect a difference between the poly balls and the competition celluloid balls. Upon arrival I knew this would be difficult because the matches were being played using orange balls.

Plan B involved finding players who had been knocked out of the competition. Gabriel Skolnick had been drawn into the quarters against his brother Micaiah and lost, and he was willing to hit with me just for fun, because once in a while officials like to play too. The seamless XuShaofa ball has a different sound that I knew he would detect, so I only brought out the Double Fish and DHS balls. We countered. He looped, I blocked. He looped, I chopped. I looped, he blocked. Then I told him what was up.

Gabriel's teammate, Felipe Morita, had lost to Micaiah in the semis. (Micaiah would eventually win the Men's Singles event with a series of upsets.) Gabriel grabbed Felipe and they tried the poly balls. As teammates, each would be familiar with how the other plays, and this would be a better test than hitting with me.

The verdict? Both players agreed that when they tried the poly ball, they didn't notice anything unusual; it was just like a celluloid table tennis ball. When they switched to the celluloid ball, they noticed a subtle difference. When comparing the balls side by side, the flight of the poly ball was slightly different from the celluloid ball. But the feel of the ball on the racket was the same.

For reference, Felipe and Gabriel are better players than I am, but they're not world class. As more people test the new balls I'm sure there will be different impressions reported, and I can't presume to know how the game will develop as a result of the introduction of these new balls. This is just a single test.

I expect that the ball factories started production of these balls shortly after they received word that they were approved. Even so, it may take some time before new balls reach our markets. Now that I've seen that it's not a drastic change, I'm not in a terrible hurry to get them. At some point things will change, and I have hope that it will be okay.