Why does a ball go further if toe poked

  • Thread starter Lucio
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Main Question or Discussion Point

If I kick a ball with the toe of my shoe (small area) rather than the side of my shoe (larger area), will the ball travel with greater speed and therefore travel further with the kick using the toe assuming the foot strikes the ball at the same speed?

I would be very grateful for some sort of quantified view of how much difference kicking a ball with a smaller area makes compared with a larger area. Are there some simple calculations using speed of foot, strike/impact area of foot which can give an indicative result of what the ball speed difference would be with different strike areas?
 

Answers and Replies

  • #2
mgb_phys
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No - the only thing that effects how far the ball goes is the speed you hit it, and this is the same as the speed you foot was going when the ball left contact.
The main difference is that you can swing your leg a lot faster kicking forward with your toe than sideways with the instep

(there is a small aerodynamic effect depending on the ball spinning - but for a soccer ball it is pretty small)
 
  • #3
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Does not the greater pressure of a smaller impact area have implication?
 
  • #4
mgb_phys
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If you deformed the ball it might store some energy and then 'spring' away from your foot with higher speed than being simply kicked - but I think the kicking/leg muscle direction is more important.
 
  • #5
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Force applied on the ball = mass*acceleration, which is the same in both cases, amiright?
 
  • #6
mgb_phys
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Yes but totally irrelevant! If I slowly accelerate the ball to 100mph it will go further than quickly accelarating it to 10mph.
 
  • #7
rcgldr
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It's possible that the toe kick results in more deformation of the ball, increasing the duration of the collision, allowing more energy transfer. There's some limit to this effect though, and note that most USA football kickers use the side of their foot and manange to kick the ball for long distances.
 
  • #8
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Yes but totally irrelevant! If I slowly accelerate the ball to 100mph it will go further than quickly accelarating it to 10mph.
yes it will

and slowly or quickly accelerating is the 3rd derivative?
 
  • #9
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No - the only thing that effects how far the ball goes is the speed you hit it, and this is the same as the speed you foot was going when the ball left contact.
Do you not think that there may be more compression of the ball when 'toe-poked' that if kicked normally.

The main difference is that you can swing your leg a lot faster kicking forward with your toe than sideways with the instep
Yeah, it would be interesting to see what would happen if both travelled at the same speed, as you have said it would probably have the same result.
 
  • #10
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Observation shows that a toe poke does cause a different effect to the speed of the ball compared to a wider area of the foot striking a ball. Could it be that the pressure (force over area) causes a greater energy release through the elastic recoil from the toe poke?
 
  • #11
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How much influence does the elasticity of a football cover have on a ball football

A number of people have kindly pointed out that the surface area of impact where a ball is truck does not effect the speed of the ball in terms of the laws of forces. What about the additional factor of the elasticity of the football casing and inner materials. If a ball is toe poked the foot goes deeper into the ball because of a greater pressure (force/area) than if the ball is struck with the side of the foot. Does the greater strectching of the football casing material with the toe poke produce a more "energetic" reaction?
 
  • #12
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Law of elasticity PE=.5 * k * x * x

If potential energy stored in elastic material is PE=.5 times k (constant) times distance of displacement (twice) then does a toe poke to a ball which causes more elastic displacement generate more potential energy than if the ball is struck with the side of the foot. The above equation suggest it does and therefore ball is imparted with more energy.

Can someone who knows pls advise!!
 
  • #13
rcgldr
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If the force generated by a persons kick is not reduced less than the increase in distance the force is applied because of the larger dwell time due to the larger deformation of the ball with a toe kick (versus an insole kick), then the total work done will be higher, resulting in more energy and a higher speed.

As I mentioned before, note that most USA football kickers use the side of their foot and manange to kick the ball for long distances. I'm not sure if this is for control or for distance.
 
  • #14
Borek
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For control. Or at least that's what my PhysEd teacher said long, long ago.
 
  • #15
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It is indeed true that the smaller surface area of a toe kick will create a greater deformation of the ball compared to a side kick, at low speeds i.e... short to medium passes.

However, there is a limit to how much the ball will deform, and a limit to the amount of KE this deformation will add the ball. After a certain amount of force, it becomes much more beneficial in terms of energy transfer and control to strike the ball with the bones on the top and inside of the foot.

The angle of attack created by using this portion of the foot allows for the highest possible force at the bottom of the swing because the angle allows for you to use not just your leg muscles, as in a toe kick, but your torso, back shoulders, arms (in fact your entire body goes into it) all provide extra momentum and energy that can be concentrated directly in the foot.

Also, the toe itself actually deforms much more than the hard bones on the top and side of the foot, canceling out the greater pressure from the smaller surface area. And if you think about it, the surface area of the toe (while wearing shoes) is really only slightly smaller than the bulge of bone on the top-inside of the foot, the first metatarsal I believe.

So in summary, yes a toe kick will be more powerful at low speeds, however you lose almost all control. It is ALWAYS beneficial to kick with the side of the foot, whether passing, lobing, or clearing. and especially in the latter two.

Just a side note, I played high level soccer for several years and have had this very same conversation with several coaches, Lucio, if you are on a team, I would imagine that your coach could and will demonstrate physically my points here. Best of luck!
 
  • #16
rcgldr
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One exception would be Tom Dempsey, a USA football field goal kicker that had some type of foot damage and used a wooden shoe for a "toe" kick. He set a record of 63 yards, but this was before the goal post were moved 10 yards away from the 0 yard line.

http://en.wikipedia.org/wiki/Tom_Dempsey
 
  • #17
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Many thanks for the comments. Which are the physics equations which most relate to this? Is it the PE=.5*k*X*X where X is the displacement. From an experimental point of view if you had two fixed hard artificial feet one with impact area A and the second larger one with impact area 2A, assuming a ball (with same elastic properties and inflation etc..) is projected towards both of these what is the relative energy/speed which the ball would rebound from each of these?

Many thanks for the comments.
 
  • #18
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Are there any data that show this effect?
 
  • #19
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Hi everybody,

I agree with robertm, I think that biomechanical reasons are the most important in this problem. Shooting with the toe is a "1D" movement as all your articulations will rotate around the same axis. Shooting with the side of the foot requires a lot of muscles to be "twisted", articulations rotate around different axis: the maximum velocity of the foot is less than in the first case.
 
  • #20
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If the problem is changed and considered as a ball striking a stationary but firmly held object what is the difference in the return energy (in the ball) when the ball strikes an impact area of size A compared with an impact area of size 2A (ie the difference in the ball striking a small area comapred with a larger, flatter area).

Going back to the earlier post - which are the physics equations which most relate to this? Is it the PE=.5*k*X*X where X is the displacement. From an experimental point of view if you had two fixed hard impact points with impact area A and the second larger one with impact area 2A, assuming a ball (with same elastic properties and inflation etc..) is projected towards both of these what is the relative energy/speed which the ball would rebound from each of these?

Many thanks for the comments.
 
  • #21
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If the problem is changed and considered as a ball striking a stationary but firmly held object what is the difference in the return energy (in the ball) when the ball strikes an impact area of size A compared with an impact area of size 2A (ie the difference in the ball striking a small area comapred with a larger, flatter area).
A situation like this is very subject, and would depend on a large number of factors. If you have a specific situation in mind, I would suggest posting the question in the introductory physics help forum. Best of luck lucio
 
  • #22
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I've done my best but I just can't get a ball to travel as far with my toe as I can with a proper kick going for distance. My left foot does kick further with the toe than inside of the foot, but I believe this is down to technique. I've kicked more often with the right than left.
There are many variables here, if your talking area per force, the wider instep provides the greatest distance by far, compared to the pointed toe. I think it comes down to ability to provide the ball the best trajectory. When you talk about kicking balls with your foot I assume your including gravity in your equations.
 
  • #23
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Assuming that the ball is of the same manufacture and pressure with the same degree of cover and ball elasticity, if it is projected towards two impact points at the same speed the only difference being that the first impact point is an area of A and the second impact point is an area of 2A, will the ball be returned with the same energy?

If the smaller area exerts a greater pressure on the ball (ie Force/Area) then that point pressure from the smaller area will be greater than that exerted by the larger area. That being so then it would follow that the smaller area object would effectively poke into the ball a greater distance than the larger area object. Using the equation PE = .5K * X * X (where X equals displacement) then there is a greater PE in the ball as a result of the ball striking the smaller area object. To provide a specific visual example consider the objects as the flat ends of 2 cylindrical metal bars with different diameters. The bars being held firm and the ball being projected towards the end of each bar head on at the same speed. The ball striking each bar end must result in a different speed of rebound purely based on the consideration of the laws of elasticity which relates stored energy PE to the distance of displacement squared. I recognise there may be many other factors, but can these be assumed as the same for this comparison?

Many Thanks

Lucio
 

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