The Trigonometry of Foot Faulting

Discussion in 'Tennis Tips/Instruction' started by Z-Man, Aug 4, 2008.

  1. Z-Man

    Z-Man Professional

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    Just like everyone else here, I have a regular opponent who foot faults. Just before he makes contact, his left foot lands about 2.5 feet inside the baseline. It drives me nuts.

    After playing tonight I started to wonder. Just how much of an advantage is he getting? So I dusted off my high school trig and tried to calculate two things: 1) A 1ft footfault is like being how many inches taller? 1) A 1 ft footfault is like the net being how many inches lower?

    It's been 15 years since high school, so I'm hoping you guys can check my math. Here's what I came up with:

    1ft = 1.71in taller
    2ft = 3.43in taller
    2.5ft = 4.28in taller

    1ft = net .6in lower
    2ft = net 1.24in lower
    2.5ft = net 1.56in lower

    For the first calculation, I figured the angle from the top of the net to the service line. Using that angle, I figured the height of the contact point at the baseline that would allow you to hit the ball straight across the top of the net to the service line (not taking into account the width of the ball). Then I shortened the distance to the net, and using the same angle, calculated the height needed to hit straight across the top of the net to the service line.

    For the second calculation, I kept the contact point height constant and calculated the angle to the service line, which increases as you foot fault. Then I used those angles to calculate the extra inches of net clearance you get as the ball travels across the net to the service line.

    Hopefully those of you who are smarter than I am can check my math. If my calculations are correct, footfaulting seem to be a real advantage. I would love to be 4 inches taller without sacrificing mobility, and my flat serve would be smoking if the net was an inch and a half lower...

    CHEATERS!!!!!!!!!!!!!!!!!!!!!!
     
    Last edited: Aug 4, 2008
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  2. YULitle

    YULitle Hall of Fame

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    You're gaining more than just physical height or a lower net. You are striking the ball farther forward than you typically would, all else equal, this reducing reaction time.
     
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  3. Z-Man

    Z-Man Professional

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    Yes indeed! And you also hit that first volley closer to the net, giving you an unfair advantage on your second shot as well. It's a double cheat!
     
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  4. YULitle

    YULitle Hall of Fame

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    Triple, even!
     
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  5. Steady Eddy

    Steady Eddy Hall of Fame

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    Consider the triangle formed by the net, (in a vertical sense), the court, (from net to service line), and the hypotenuse connecting the net to the service line. the rise is 3 ft, and the run is 21 ft, that ratio reduces to 1/7. So every foot of cheating make you 1/7 of a foot taller. I think that's the easiest way to think of it. No need for trig functions, (although you can do it that way). Just geometry.
     
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  6. Z-Man

    Z-Man Professional

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    That's a much easier way to figure it...
     
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  7. chess9

    chess9 Hall of Fame

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    Cute thread.

    The line from the serve to the LZ (landing zone of ball) is not a straight one, btw. ;) Hypotenuses like straight lines. But, the important issue is not the height advantage, but that the LZ error rate declines at a given velocity.

    But, having said all of this, foot faulting is illegal. Those who do it should suffer much more severe consequences than they do. In pro matches they are rarely called (in all fairness, the pros might barely touch the line and any advantage is very minimal), and in local amateur matches calling a footfault would be tantamount to declaring nuclear war. I've seen old men fighting over the issue. Not nice.

    -Robert
     
    Last edited: Aug 5, 2008
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  8. Steady Eddy

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    YU, so are his calculations correct?
     
    Last edited: Aug 5, 2008
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  9. YULitle

    YULitle Hall of Fame

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    I didn't bother to check them. Seems inconsequential, to me.
     
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  10. RakettoKozou

    RakettoKozou Rookie

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    Those hackers... they somehow hacked life to double cheat!

    TURN OFF YOURR HACKKKSSSS
     
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  11. YULitle

    YULitle Hall of Fame

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    Yeah, there needs to be a Punkbuster for tennis! :D
     
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  12. RakettoKozou

    RakettoKozou Rookie

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    I think that's called a line judge/umpire. xD

    They bust those punks good.
     
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  13. consistency wins

    consistency wins Semi-Pro

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    Screw the trig. Just forewarn them they are faulting and then start calling it.

    See...math is simple! Even trig!
     
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  14. chess9

    chess9 Hall of Fame

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    LOL! Good point.

    -Robert
     
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  15. Kaptain Karl

    Kaptain Karl Hall Of Fame

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    a) That's a HUGE FF!

    b)Do you know he steps in that far from watching him play others? Or do you just "think so" from almost 80 feet away?

    - KK
     
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  16. Fedace

    Fedace Banned

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    FootFaulting is Legal in amateur tennis. and those who call it will be kicked out of the league.
     
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  17. Noaler

    Noaler Semi-Pro

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    WhAT?!!??!? Define amateur tennis?
     
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  18. Fedace

    Fedace Banned

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    Those USTA leagues that can never get the ratings right and has captains that will do anything to get to the nationals, even give their first born.....:)
     
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  19. chess9

    chess9 Hall of Fame

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    Spot on!

    -Robert
     
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  20. Fedace

    Fedace Banned

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    I must say, i respect your wisdom on this controversial matter.:)
     
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  21. Kaptain Karl

    Kaptain Karl Hall Of Fame

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    Source, please?

    - KK
     
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  22. martin8768

    martin8768 Rookie

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    im glad i dont live in the states and have to worry about what sounds like a horrible experience that is USTA leagues
     
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  23. Bungalo Bill

    Bungalo Bill G.O.A.T.

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    LOL, I was just thinking this. My gosh, 2 1/2 feet? I have seen a whole foot in or a foot over the baseline, however, I have never seen a player in the court 2 1/2 feet! Wow!

    Without any math, it is obvious to me he has an advantage in his serve. When I serve from the service line drilling a players return of serve, it is painfully obvious the advantage I have.

    The other advantage is whether he is coming to net following this serve. If he doesn't and you can get the serve back, perhaps you can stick the ball near his feet while he back peddles from no-man's land.

    Anyway, two and a half feet, wow.
     
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  24. dman72

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    I noticed that a guy I play footfaults on every serve from watching him practice. His right foot slides across the line when coming forward to jump in. His serve isn't that great anyway, so I don't care, but, it's a touchy subject to bring up.
     
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  25. Bungalo Bill

    Bungalo Bill G.O.A.T.

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    Good point. I played with a person in a regular group and he foot faulted every single time. Sometimes his foot was clearly passed the baseline and he was a net charger.

    At first, several us complained but got nowhere with him. His saving grace was he was the match maker and was willing to do the work to find and line up players each weekend.

    If he had a huge serve, and it really made a difference, I think we would have complained more. We just eventually accepted it and moved on. We weren't playing at the US Open or anything.

    So I am with you on that.
     
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  26. dman72

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    And also, I like this guy and I know the he isn't doing it on purpose because he's too decent.

    I also failed to mention that he does kick my butt most of the time...I think I've beaten him once out of about 30 matches, and I consider a 6-4 6-4 loss a good day.
     
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  27. Bungalo Bill

    Bungalo Bill G.O.A.T.

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    Yup, I agree with you completely. It really depends on a lot things, most the time I take it as a challenge or a "whatever". As you mentioned, it can be a touchy conversation. :)

    However, this 2 1/2 feet thing might spark a delightful conversation with me. I might draw the line there.
     
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  28. Bungalo Bill

    Bungalo Bill G.O.A.T.

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    When? Where? How? Who? Are there rules we can look at or can you point us to a reference on this?

    In my entire life, I have never heard footfaulting was LEGAL. I have never heard of someone getting kicked out of a league for calling it.

    A player footfaulting has an advantage over the other player no matter how small. Rules in tennis are established to make it as fair as possible for both players to win a point.
     
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  29. paulfreda

    paulfreda Hall of Fame

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    Foot faulting is Legal as long as you keep your tongue in your cheek .....
     
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  30. Noaler

    Noaler Semi-Pro

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    Ok...didn't quite get that but it doesn't matter. i don't foot fault anymore anyway.
     
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  31. chess9

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    You and BB need some better filters. ;)

    -Robert
     
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  32. Bungalo Bill

    Bungalo Bill G.O.A.T.

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    lol, I guess so!
     
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  33. Z-Man

    Z-Man Professional

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    There is a tournament this weekend--I'll try to sneak some pics. You guys are going to laugh. I don't know why everyone else seems to tollerate it. I think it's because most of them also footfault a little. I'll tollerate an inch or two, but yes, his footfault is so bad you can see it's about 2.5 feet--even from 70-80 feet away. It gets worse as the match gets tighter.

    The guy does serve and volley, and he's crazy quick. Needless to say, his first volley is at the service line or closer. He also has the annoying habit of quick-serving you. You look up and the ball is in the air and he's already half way to the net. It's really stupid because the guy is a very good 4.5. He doesn't need to cheat, but his serve is the weakest part of his game, so maybe he thinks he needs an edge.

    He does a little quick step inside the court and makes contact right after he plants his forward foot. Imagine standing at the service line and taking the biggest step forward you can make without losing your balance. The back foot is on top of the baseline. On Monday night after he aced my partner out wide for the 5th time from 2.5 feet inside the baseline, I started complaining. He hit two double faults in his next service game and we broke him. The fact that he couldn't get the serve in from behind the baseline shows the extent of his problem. Everyone acted like I was the biggest jerk of all time--including my partner who admits to footfaulting himself and is known for dodgy line calls.

    All of these guys are my friends, and there are only a handful of 4.5+ players in the area, so I guess I should just put up with it, but I can't stand being cheated. Yes we are playing for "fun", but 4.5s don't just play for fun. We play to win. That's how we became good tennis players.
     
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  34. Bungalo Bill

    Bungalo Bill G.O.A.T.

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    I dont know if I will laugh. :)

    You guys do tolerate a lot. There is no way this guy would get away with it if he was playing me. It would be settled in some way.

    That is crap dude. I would call a let, everytime he tried to quickserve. In other words, I would bring in controversy and attention to what is happening in my court. He just wants the benefit of cheating and the benefot of his skill to beat you.

    But he is cheating. He is cheating in every sense of the word. Where are you guys on this!!!!!! This is crap!

    There it is! I would be complaining up a storm! I would be willing to call "let" or footfault on every single serve and if he did it twice, I would walk to the other side of the court and wait for the serve.

    You need to totally disrupt this guy.

    Who cares, you found a way to beat him. I would keep doing it. I would love to create that controversy just so everyone could talk about it. Tell them what you can tolerate and what you can't.

    If you can tolerate the foot just over the line, that is okay, but quick serving and 2.5 feet in the court?



    Hahaha, not me. I would still call a let or something. If you really want to tolerate it, do it on occasion like when you are in a bad mood.
     
    Last edited: Aug 7, 2008
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