Tennis – Putting the Momentum Theory to Bed


I too find the theory of momentum in pro sports to be gross, Genie. Source:

The theory of momentum in pro sports has been dissected by stats people who know a lot more about stats than me, and their conclusion is unequivocal – it does not exist. According to the mathematicians, going on a 10-0 run in the NBA, in and of itself, has nothing to do with extending that to a 16-0 run. Stats gurus like John Hollinger have studied the hot hand fallacy - the mistaken belief that making five shots in a row has anything to do with the likelihood of success of the sixth shot.

While I’d challenge that momentum does not exist in basketball – teams, for example, often need timeouts when they’re rattled on the road to calm themselves down – I will argue momentum in pro sports is extremely overblown. Athletes at this level, while not immune to performing worse due to repeated failures, are mentally strong and too skilled to get crushed by fake “turning points” that commentators love to allude to. While this page is usually reserved for basketball talk, I’d like to turn down the noise on momentum by discussing another sport – tennis.

Take Wednesday’s US Open Match between Canadian Frank Dancevic and Portugal’s Joao Sousa. Dancevic held a 6-1 lead in a first set tiebreak, with five set points in hand. Sousa came back to win the next seven points and the set.  ”That’s a turning point in the match. I sense a shift in momentum,” rang the inevitable refrain from the commentator. Granted it was devastating for Dancevic to drop a set in that fashion, but Grand Slams are best three out of five, so there’s time to bounce back.

Sure enough, Dancevic won the next set.

Then dropped the next one.

Then won the next one.

The fifth set went to a tiebreak. “I think Sousa’s gonna win because Dancevic’s probably still thinking about the first set collapse,” blared the colour man. It seems illogical that Dancevic would leave aside the pain of the first set loss for the middle three sets and first 12 games of the fifth, only for it to return in the tiebreak. Wouldn’t the immediate shock of losing such a lead affect his second set results, which he won? It’s unreasonable, but terribly convenient, to attribute the result of an event three hours after the first event occurred (the fifth set occurring three hours after the first).

Another example – Eugenie Bouchard’s opening round match at the Rogers Cup. Bouchard was having one of the best seasons on tour – three straight Grand Slam semi-finals, with one Finals appearance in Wimbledon. Her opponent – Shelby Rogers, the 86th ranked player in the world. The first set was bizarre – Bouchard looked lost, getting pummelled by her unranked opponent, barely able to keep rallies alive. She lost the set 6-love. At one point her coach came to her chair. Bouchard, in shock, said “I want to leave the court”.

Cue the momentum-pushers. Loosely quoting, “how can she recover, what with the momentum on her opponent’s side?”

2nd set result – 6-2 Bouchard.

Cue the momentum-pushers. “She’s found herself.”

3rd set result – 6-0 Rogers.

“She never recovered from the first set.”

You see where I’m going with this?

Watch how many times a commentator posits whether a certain point, game or set is a “shift in momentum”, then take note of the actual result after. Ask yourself, were the results immediately following a great shot, or awful blunder, a cause of that person winning or losing, or was it just a single point in a match with dozens of points.

In pro sports, athletes are too good, physically and emotionally, to get run over by failure. They’ll win or lose (mostly) because of skill, not because of being jarred by an unforced error.



  1. Rob says:

    I think I disagree with some of this. No matter how good an athlete is or how mentally tough they are, doubt can creep in and take over. It may not be “momentum” because that’s impossible to define, but, there are tons of examples, of athletes crumbling mentally due to things that have happened before, thinking they’re fine, and then having it all come crumbling down again. I guess, what I’m saying is that, it’s a mistake to think that a) previous results don’t affect an athlete’s mental state, even if they’ve seemed to put things in the past, and b) that, “mental toughness” works in a linear way.

    I do agree that momentum is largely bunk and is impossible to predict, but I think things can stay with an athlete and affect them throughout a match, or a season, or a career. I guess, it’s more of the analyst trying to shape the narrative.

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