Parabolas in Soccer

I started to play in a co-ed soccer league in Alaska when I was three and continued playing when I moved to Oregon. As a little kid you shift positions around a lot so that everyone gets a chance to experiment with the different sections of the field. I was usually, however, put as a defender because of my size. It wasn't until I got to Oregon that we started to play in more secure positions, places we could think of as "ours". It was then that I was asked to play in the goal. I fell in love with this position, the most underrated players in the game are goal keepers. Being a goalie requires full body strength and speed- also,a whole lot of fearlessness. I have gone through many injuries because of the intense position, including breaking both bones in my lower leg when I was in 6th grade. 

Being a goalie takes more than just running aimlessly around a field. You have to be able to gauge when to stay back and when to come out. You have to be able to read a players body language to know where they are shooting. And you have to have quick body  motions whether for sprinting at a player or getting up after a dive. One of the most showy skills that a goalie must have are good punts and throws. Part of the position is going to special training for other goal keepers in you club. At this training a player will repeat one movement over and over again until they have mastered the art. Parabolas show up in many of these motions. 

The most obvious is the punt. A player must alter their body and technique depending on where they want the ball to be placed on the field. If you want the ball to land close to you the top of your foot will stay in contact with the ball for longer, causing the ball to go higher and come down closer. A mathematical term for this would be a vertical shrink and you would make the leading coefficient <1. You can apply this to a "chip" as well- a kick that is used during goal kicks or when a ball is on the grass and you want to lodge it into the air. If you want the ball to land farther away from you a player will decrease the amount of time their foot is on the ball and cause a vertical stretch. 

 

(Both photos above are of Hope Solo, the goal keeper for the United States women's soccer team at the last women's World Cup and Olympics. She was born and raised in a town just north of where I lived in Oregon.)