What's the Problem With the Line Drive Kickoff (and how it relates to Rugby and Soccer)
As an Eagles fan, the first half of Sunday's game introduced me to a brand new torture device in the NFL, the line drive kickoff. With the rule changes around kickoffs over the past two years, new and inventive ways of trying to give a team an advantage on kickoffs have appeared, and none seem to be more effective than the line drive. After Rams scores, the Eagles started their next possessions at their own 20, 19, 17, 14, and 21 yard lines, with two muffed kicks in all of that. Compare that to the league average of a starting field position at the 30, and that is a significant difference. And yet, that is not even the worst example, where last week in the Steelers Seahawks game, Kaleb Johnson watched one of those same line drive kicks bounce off his head and into the endzone, where Seattle scored a TD.
As frustrating as it is to be on the receiving end of the line drive kick, it has long been a strategy in football and other sports to cause mayhem. The squib kick has been used in football for decades as a way to mitigate return threat on kickoffs due to their difficulty in being fielded. In rugby, low, fast kicks put pressure on defenders to try to grab the ball without knocking on and causing a penalty. Even in soccer, there has been shown to be extra difficulty in defending long throws from the touchline compared to other more balls hit from feet from similar areas and situations.
The million-dollar question is, why do some of the greatest athletes in the world, who do not struggle to catch and track balls that fly high in the air and time their responses perfectly in their ability to react to them, struggle so much with these altered deliveries?
My answer is simple, the audiovisual cues that the players rely on for these scenarios change their nature either so quickly, or in such a distinct way, that it causes the chaos intended by the deliverer of the ball almost guaranteed.
Chang and Jazayeri demonstrate that the brain's ability to track objects depends not only on kinetic information, such as the distance and velocity of an object, but also on additional temporal cues, including how far an object travels within a given time. Additionally, Sinnet and Kingstone demonstrate that grunts have a detrimental effect on a tennis player's ability to quickly determine the direction of a tennis ball, due to the loss of the audio cue of a ball hitting a racket.
In football and rugby, the difficulty in fielding these kicks appears relatively straightforward when examining the evidence. One calculation is performed by the receiving player when the ball is kicked, and for each subsequent bounce, a new calculation must be performed to evaluate the ball's path. The harder it is hit and the closer to the player a bounce occurs, the faster the time decreases to make an accurate assessment of where they need to be to field the ball. Knowing this, it is rather surprising that we do not see this technique utilized more often, given its apparent detrimental effect on performance. I would love to gain access to, or highly suggest that someone with access to, the data necessary to prove this in real world scenarios.
Now the soccer long throw does not appear so straightforward, but I posit the extra difficulty comes from the loss of the audio/visual cue of a ball being kicked. Initially, I thought it had to do with the less elliptical flight of the ball, but that is not true for how all long throws are thrown, yet all long throws show an advantage. So where does it come from? The Sinnett and Kingstone article shows how audio interference impacts tracking ability, but also shows that audio can help tracking. A grunt diffuses feedback, while a racket hit delivers it. Much as a soccer ball kicked offers audio feedback, a throw does not. The very nature of a throw vs a kick also changes the initial tracking from what is to be expected into something like an eephus pitch. A pitch famed for how easy it seems to be hit, that MLB hitters surprisingly do not fare that much better with. So give a player something already difficult to do (tracking a ball) and add in the loss of one of their most significant data points (the audio/visual cue of a ball being struck) and voila, long throw advantage.
I hope you enjoyed today's departure from the norm here, but these are the questions I constantly have rattling around in my head. While my wife finds this stuff interesting as well, I enjoy staying married and so need another outlet!
If you have thoughts on this, competing theories, or arguments against me, I would love to see them, and if not, see y'all next time.
