The Effect of Serve Speed

All else equal, you want to serve harder. But how much does it really matter?

That’s a more difficult question than it sounds, and I don’t yet claim to have an answer. In the meantime, I can share the results of some data crunching.

In 2011 U.S. Open matches covered by Pointstream, there were more than 9,000 first serve points. The server won almost exactly 70% of those points. About 11% of points were aces, and another 24% were service winners.

To see the effect of serve speed, I looked at four outcomes: aces, service winners, short points (three or fewer shots), and points won. It’s no surprise that each type of results happens more on faster serves.

Below, find the full numbers for serves of various speeds. The finding that sticks out to me is the small change in service points won from the 95-99 MPH group to the 115-119 MPH group. It may be that the modest increase–put another way, the surprising success rate at 95-104 MPH–is a result of strategic wide serves, or the better ground games of the players who hit slower serves.

So as I said, there’s much more work to be done, identifying the effects of faster serves for individual players, looking at deuce/ad court differences (for righties and lefties), and the results on different serve directions.

MPH      SrvPts   Ace%  SvcW%  Short%  PtsWon%  
85-89       140   2.1%  17.9%   47.1%    55.0%  
90-94       275   0.7%  21.5%   47.6%    63.6%  
95-99       546   2.2%  18.5%   48.4%    66.1%  
100-104     885   4.2%  24.6%   51.0%    66.0%  
105-109    1400   6.4%  29.3%   56.6%    68.7%  
110-114    1524   8.7%  34.0%   57.3%    69.1%  
115-119    1487  12.2%  35.9%   60.8%    69.4%  
120-124    1553  16.1%  40.1%   65.2%    73.2%  
125-129     941  21.5%  48.1%   72.4%    76.3%  
130-134     353  29.7%  58.4%   77.3%    84.4%  
135-139      66  27.3%  65.2%   80.3%    89.4%

7 thoughts on “The Effect of Serve Speed”

  1. That fits in with what I have noticed about Del Potro (among others). Experts up to and including Pete Sampras and Mark Philippoussis have raved about his service, but when you watch him play a match you rarely see him serve at over 130 mph, and his second serves especially often come in at well under 100 mph. And he doesn’t serve very many aces – although he does seem to be able to send them down when it really matters. It’s almost as if he wasn’t bothering to squeeze as much out of his serve as he could! (Maybe he’s modelling his game on Chela and Monaco?)

    Even when Delpo does serve relatively slowly, however, you still hear commentators exclaiming how “He really crushed that one!” or “That was a rocket serve!” It’s almost as if they are reacting more to the way the receiver is stranded than to the ball’s raw speed.

    1. Good points — so much of interest about Delpo’s game. One of these days I’ll look at ‘clutch’ serving, and I’d expect him to come out well. Also it will be interesting to see who gets the most aces/svc winners/etc out of the slowest serves — Federer is the one who is always praised for hiding his intention, and Delpo excels there as well.

  2. I wonder if after everything else is considered, it’s worth adding in what percentage of service games were won by servers at different speeds? I realize this depends on the rest of the server’s game and his opponents, and that the server’s average speed is not a constant.

    Great start on this – very interesting.


    1. Thanks. I’m hoping to break everything down at the point-by-point level, and build up from there. Ultimately, I’d like to know what the benefit is (in points won, games won, matches won, etc.) of each 1mph increase in serve speed.

  3. Interesting results! Glad you did the work! A few notes:
    1) Due to the elimination nature of the US Open, Pointstream cumulative stats are skewed in favor of better servers and more successful players (which are correlated). For example, Mardy Fish plays several matches but Michael Russell played one (Fish serves 115-130 and Russell serves 90-110). If 400 Fish serves are in this database and only 80 Russell serves, you get the point. Not only the better server but better player so results can be skewed. Which is why we don’t see as much data with serves under 110 mph.
    2) Measurements of serves (Doppler) lose accuracy on wide serves which could also distort date on success of serves 90-105 (may be wide).
    3) The leveling out of serves 95-120 mph may well be due to averaging effect. Most touring pros making the US Open are ranked in the top 110 (and qualifiers) so they tend to be the best servers. And maybe 60-70 of these guys average 115 mph or more on the serve. Therefore statistical data makes their results look ineffective against the top 20 players. It distorts the success of a very good server (who can serve 115 mph) but is now playing against a Nadal or Murray). e.g, a player ranked 50 appears to have an ineffective serve (false result)
    4) To improve results (get rid of skew). Just get stats on maybe 20 servers ranked 40-60 in matches where they win and lose (e.g, 2 matches won, 2 matches lost) against higher/lower ranked players. Use only 150-200 serves from each person so there’s no skewing of data.

  4. Here a couple of quick comments from college coaches I know about service speed:

    1. Agassi said it well…it’s not great your serve is, but how great you’re “holding” game is that matters. Sampras’ serve was enormous, not because it was faster than anyone’s but because it had the great spin to speed ratio, which created more movement. Great athletes get used to speed, almost no matter how fast it is, which is why fast ball closers can only get away with pitching for the last inning…after that, everyone is used to it!

    2. Fast balls don’t change trajectory as much as other types of balls and there predictability is more difficult. Why sometimes in tennis, mishits or slow “easy” balls are missed. For ball moving downwards, it harder for the brain to process than a fast ball (not dropping as quickly).

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