Exploding into the Ball

[5263]

Originally Posted by sureshs

So this is a physics question I always had. If a person standing on a scale tenses his leg muscles to try to "increase" the force on the ground, will the scale show a higher reading? No.

I just tried it now and it is confirmed.

Did you really have to get on a scale to test this?

[Cheetah]

... and I should add that the most important part the legs should play is balance.

[Cheetah]

Originally Posted by 5263

Did you really have to get on a scale to test this?

No but if you press on the scale with your legs you will get a higher reading.

[rkelley]

Originally Posted by sureshs

Very interesting, and something I wanted to do for a long time.

Do you know what is the main cause of friction? Your weight. The frictional force is usually a coefficient (less than 1) times the weight.

So this is a physics question I always had. If a person standing on a scale tenses his leg muscles to try to "increase" the force on the ground, will the scale show a higher reading? No.

I just tried it now and it is confirmed.

So, pressing against the ground cannot increase friction.

It can only provide a springboard to rise.

A niggle and one bigger issue in the above.

First the niggle:

Your weight doesn't cause friction. Friction is caused by the characteristics of the two materials in contact, namely a tennis court and a shoe.

One way to model the frictional force created by two materials in contact is to assume that the force generated is less than or equal to the force between the two surfaces multiplied by a coefficient (as suresh said called the coefficient of friction). For most material combinations it is less than 1.

Now the bigger issue:

While just tensing the muscles in your leg won't change the force between your shoe and the ground, bending your leg and lowering your body, like you would setting up for a forehand, and then straightening your leg most certainly will increase the force. Try it on your scale.

As far as hitting forehands goes I 'm not sure how much of a difference any of this makes. I think the more salient point is that bending your back/outside leg in your set-up allows your leg to help drive your hips around. The legs become an important part of the kinetic chain and add to your power.

[Cheetah]

If you want to see some good leg action James Blake's qualifying match is just starting now live on aussie open tv on the official site.

[ShoeShiner]

Originally Posted by crazygamer2091

. . jumping . .? . . to add consistency and more power . .

I do not think that jumping could help you adding consistency and more power. I think jumping could help you reaching ball and creating more angle shots.
If you are not fit enough, do not try to jump too much. It consumes too much energy and causes knees injury.

[5263]

Originally Posted by Cheetah

No but if you press on the scale with your legs you will get a higher reading.

Of course, I know what you mean, but not sure about that other comment.

[Cheetah]

Originally Posted by 5263

Of course, I know what you mean, but not sure about that other comment.

you mean 'leg action'?

was referring to james blake and his patented 'sit and lift' FH.

[5263]

Originally Posted by Cheetah

you mean 'leg action'?

was referring to james blake and his patented 'sit and lift' FH.

I was talking about sureshs wondering if tensing you leg would produce more
wt on the scale.

[Cheetah]

Originally Posted by 5263

I was talking about sureshs wondering if tensing you leg would produce more
wt on the scale.

idk. maybe he was kidding.

[directionals]

Here's a nice video analysis of Fed using his trunk and front leg to generate power in neutral stance: http://www.youtube.com/watch?feature...HJGpypQE#t=16s