Hi, this is Florian Online Tennis Instruction. In today’s video I want to talk to you about how much knee bent you should have
on your topspin groundstrokes if you follow our videos you know that
we often use the old Vic Braden saying of sit down in the chair and come back up and some people have commented, well I
never see players get that low and that’s a very good comment actually, so I
want to clarify that here in this video so when we are hitting topspin
groundstrokes, power is generated from the ground up we need to coil our upper body, we coil
our legs we bend and then we uncoil and then we go from down to up and that’s a
very important power source on our topspin ground strokes. And most of the
tennis that I see at the club level students that come to our clinics looks
something like this. Ok there’s very little down and up
movement and there’s very little knee bend. And because most players rarely
bend or get low enough, we tell them to sit down in the chair and then come back
out of the chair. Now if I would actually sit down in a chair, it would be this low, now I’m not going to get that low when I
actually hit my shot so it is an exaggeration. I wanted to
clarify that. So how low do we usually get? Ok so if I
hit a regular topspin forehand shot it’s going to be something like this. If
you look at the angle here it’s not anywhere near a 90 degree angle,
but I’m not straight up either. It’s somewhere in between around here. This
would be on a normal shot a good knee bend and then I uncoil from
here and I come back up and I can generate a lot more power on my forehand
if I have that down and up movement included in my swing. Let’s look at this from the side angle
as well. So basic forehand shot: My knee bend is going to be something like this
right here and then I hit and come back up. Now, it of course varies with what
kind of a ball we’re dealing with. Let’s say I’m dealing with a very low ball
I’ll probably get around this low. It’s still not quite sitting down on the
chair but it’s close enough. And then if I’m dealing with a higher
ball I’m not going to bend that much, but I still
need that push off so I need to go down on against the high ball down, push off
and that’s very very important. If we don’t have that little bit on the high
ball we can’t generate a lot of power. But
let’s look at this in super slow motion. First let’s look at a regular shot here:
The ball is going to be about waist high at contact and right here you can see
how much I bent my knees and this is a very significant knee bend. It is not
quite sitting down in the chair, but it’s actually not that far away from it.
From here i can now uncoil my upper body as well as my legs, the weight is moving forward and upward
and that’s how I can generate
a lot of power. Now let’s look at a low ball where I’m
going to contact at around knee level and of course I’m getting even lower here. Take a look right now, see how low I am.
There’s even more knee bend and most club level players don’t get anywhere
near this low when they deal with these kinds of low shots. From here I can then
uncoil again and generate a good amount of power. Last but not least let’s look at the knee
bent on a high ball above shoulder level. Take a look right here! There’s still a
significant knee bent – now of course I’m not nearly as low as on the other shots, but
I need this amount of knee bent in order to then push off, uncoil and generate
power. Alright so now you have an idea of the
right amount of knee bent on three typical shots: an average shot, a low shot and a high bouncing ball. Now
it’s going to be the same when you’re hitting a one-handed topspin backhand
or a two-handed topspin backhand. Keep in mind that most likely you’re not
bending enough and also keep in mind that there is a down and up movement. We
do not stay down as we hit the shot.

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Dennis Veasley

16 thoughts on “Tennis Tip: How Much Knee Bend On Topspin Groundstrokes?”

  1. You should do a video on the real contact point – which is between the feet on a neutral stance not in front. This "hit in front of foot" stuff is bad advice.

  2. Knee bend has nothing to do with topspin. Bending the knees while turning upper body clockwise, followed by stretching the body upwards while turning the upper body counterclockwise, accelerates rotation and as a result, makes a faster hit of the ball. Just watch ice skaters. This is exactly what they do to reach breathtaking rotation speed.

  3. If you look carefully at the slow motion videos of Florian's forehand, I think you can see that rising from a deep knee bend position adds a bit of rotational speed but I don't think this is a significant amount. What it does do to a greater extent is make it easier to hit with a good amount of topspin. I think this is because, for the same upward diagonal path of the forward swing, it is easier to achieve from an initially lower position. Standing completely erect requires more of a shoveling motion to generate topspin. I think it is harder to gain consistency with a stroke with a larger shoveling component.

    The other advantage of hitting with bent knees is that it provides a base with greater stability because the center of your body's mass, the core, is lower to the ground. Like a good sports car design demonstrates, a lowered center of gravity is a sign of greater stability. A maximally stable base is important in groundstrokes and in serves because the quick rotational motion of the arm, racket and trunk creates both a centrifugal and forward motion pull.

  4. A question: I sort of get the down up motion but why do these commentators on TV regularly say 'he stayed so low/down on the shot?? Sort of contradicts the process?

  5. A very important point. Once one understands how knee bending contributes to the stroke, he will never ignore it.
    Knee bend is not a power source, nor a push-off. It is a pre-requisit for body acceleration.
    When a rotating body goes from wide to narrow, rotation accelerates. (This is physics, the law of angular momentum preservation. Ice skaters use it a lot.)
    Knee bending, together with taking the racket far back and stretching the other arm, make the body wide. During the stroke, while the body rotates, a player stretches his body upwards, legs including, brings the arms close to the axis of rotation. This makes his body narrow, and, due to it, faster and faster.
    And remember: if no rotation, no acceleration…

  6. On your forehand, you need to rotate your body through contact. You stop your body rotation at contact. This results in less power.

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