Why Did My Tennis Serve Bounce Unusually Low?

[lebronJames24]

TL;DR Summary

Did a weird serve in tennis that did not follow the predicted projectile trajectory. Do not remember the ball being flat nor having uneven surfaces.

About a year ago, I was playing tennis against family and managed to have a strange service. Since I am not good at serving, I often lean forward from the service line while still keeping my feet behind. What resulted was the tennis ball having a normal trajectory before it bounced with a reduced height after the bounce. In other words, the ball had regular projectile motion until it bounced, where it had a reduced height. Does anyone know why this occurred and how I could replicate it. Also I do not remember the ball being flat nor having uneven surfaces (other than the seams which are in all tennis balls). However, I cannot remember correctly the spin on the ball.

 

[berkeman]

(thread prefix changed from "A" (Advanced Physics graduate school level) to "B" Basic level)

 

[berkeman]

TL;DR Summary: Did a weird serve in tennis that did not follow the predicted projectile trajectory. Do not remember the ball being flat nor having uneven surfaces.

About a year ago, I was playing tennis against family and managed to have a strange service. Since I am not good at serving, I often lean forward from the service line while still keeping my feet behind. What resulted was the tennis ball having a normal trajectory before it bounced with a reduced height after the bounce. In other words, the ball had regular projectile motion until it bounced, where it had a reduced height. Does anyone know why this occurred and how I could replicate it. Also I do not remember the ball being flat nor having uneven surfaces (other than the seams which are in all tennis balls). However, I cannot remember correctly the spin on the ball.
View attachment 346573

How did you measure the reduced height? Do you have a video? Can you reproduce it for us so we can try to comment?

 

[lebronJames24]

How did you measure the reduced height? Do you have a video? Can you reproduce it for us so we can try to comment?

I'll see what I can do in the coming days to attempt to reproduce this. The reduced height was not measured but visible. Additionally, the ones attempting to return it had a tougher time returning it. I know it may seem unbelievable, but I am not making this up.

 

[Baluncore]

Top spin accelerates the ball at the first bounce.
Leaning forward during the serve encourages top spin.

 

[Talent city]

I think Baluncore is right.Topspin causes ball to have less angle after rebound as pressure below the ball is lower it forces the ball to move downward. I think you were leaning much over the table, leaning forward produces the topspin.If you want to reproduce it you have to lean at the same angle as before. By the way I don't know how to play tennis.

 

[lebronJames24]

I think Baluncore is right.Topspin causes ball to have less angle after rebound as pressure below the ball is lower it forces the ball to move downward. I think you were leaning much over the table, leaning forward produces the topspin.If you want to reproduce it you have to lean at the same angle as before. By the way I don't know how to play tennis.

neither do I

 

[Baluncore]

@Talent city
Welcome to PF.

When playing lawn tennis, the ball is usually served from high overhead, over the net, so it is difficult to put topspin on the ball. But when playing against the family, you might serve forehand, which would allow a high topspin or backspin.

Serving in table tennis is different because the ball bounces on your side of the table first, but a table tennis return can be overcut or undercut to change the length, and so make it hard for the opponent to reach and return.

 

[Hornbein]

I'm no tennis expert but I've played and know from experience that topspin increases bounce and backspin reduces it. Ask any tennis or pingpong player.

Your serve didn't necessarily have backspin. Maybe just less topspin than you are used to, or something like that.

 

[PeroK]

If the ball hits an irregularity in the court, then it may bounce lower. This is sometimes called a bad bounce, as it makes the ball difficult to hit.

This can be a significant problem in cricket on a poorly prepared pitch, where you can get a variable bounce; and, in extreme cases, the ball shoots off the surface at ankle height.

 

[PeroK]

When playing lawn tennis, the ball is usually served from high overhead, over the net, so it is difficult to put topspin on the ball.

In tennis, a kick serve involves putting topspin (and often sidespin) on a serve, causing the ball to kick up off the surface, and away from the opponent. There's a short, instructional video here:

 

[Arjan82]

Well, if it is not a bad bounce (a bad spot in the surface) it may be slice or even back spin. It is definitely not top spin as that will do the opposite and make the ball bounce way higher.

If you move forward a lot you might compensate with your racket by tilting it backwards relative to your arm/body (the face of the racket would now be normal but since you're leaning forward, it feels like the racket is backwards. If you wouldn't do that the ball would bounce even before the net). If you then also pull the racket down because you are at the end of your reach, you can indeed produce back spin. This can generate a low bounce. This is not a good service however as you can not generate any power whatsoever. I've never seen a top 100 tennis player produce a back-spin service.

What also can happen is that the ball does not 'grip' with the surface at its bounces, this can be when it is wet or if the ball is very new (and the court not so good), or if you hit the paint of the line (which is generally less grippy). This wil let the ball slip over the surface also generating a much lower bounce.

The last thing that might happen is that you hit the back side of the line. Sometimes the line is a bit higher than the rest of the court. If you hit the back of that, the ball wil stay low and bounce towards the receiver much more aggressively.

 

[Mister T]

But when playing against the family, you might serve forehand, which would allow a high topspin or backspin.

This is a common technique in pickleball.

 

[rcgldr]

Pickleball - the ball is perforated to minimize any curvature due to spin. Top spin should make the ball bounce at a shallower angle, but the height will end up about the same, if allowed to reach its peak height.

Table Tennis - the ball curves a lot due to spin. In a rally or very fast serve (normally only done for show, not in a match), if the path is shallow, the angle is shallow, and the curvature keeps the ball low. If the ball is higher, the curvature causes it to curve to a steeper angle just before it bounces, resulting in a higher bounce. With top spin, the bounce angle will be shallower due to top spin speeding up ball at impact, while back spin bounce will be steeper due back spin slowing down ball at impact.

Tennis - similar to table tennis but much less relative effect. A kick serve like rally in table tennis would have more relative effect then a kick serve in tennis.

 

[Arjan82]

This is a topspin (or kick) serve in tennis. It's called a kick serve because the ball bounces up way more than normal! Look how he has to hit his backand!



Another one from Isner, hear the commentator say how it almost bounces over Djokovic's head!

 

[PeroK]

I'm sure there is a video compilation of John Isner serving against women in mixed doubles and, indeed, one kick serve goes way too high for the woman to reach!