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Big Boots

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USARugger

USARugger

John Thornett (49)
You know what the say about big boots..they can kick the ball fuckin' far.

So why is it that guys like Mogg, White, and others can smash the ball significantly further than other players? This is a question I've never really been able to get a straight answer on. Is it leg strength, technique? I just can't seem to find a common denominator. For example, Mogg is built like a greyhound, White is a nuggety little guy and Leigh Halfpenny is built like a stunted Hercules yet they can all peel the hide off of a rugby ball.

Why can they do this? Why can't others?
 
USARugger

USARugger

John Thornett (49)
ChargerWA said:
It can only be physics. They must have better leg speed to impart more energy onto the ball.
Click to expand...

Wondering how exactly accomplish this and if it's something that can be trained or not. There are such huge differences between the physiques of some of these guys..

lewisr

Can't be entirely timing, the ball is sitting still when it's on the kicking tee.
 
lewisr

lewisr

Bill McLean (32)
USARugger said:
Wondering how exactly accomplish this and if it's something that can be trained or not. There are such huge differences between the physiques of some of these guys..

lewisr

Can't be entirely timing, the ball is sitting still when it's on the kicking tee.
Click to expand...

Of course power plays a role. I'm just saying that timing is one of the key aspects. My Brother for example (15 and a spindly bugger at about 50 kilos) can drop kick and slot a goal from 50 out - no dramas. I have a mate who is an absolute string bean and has pulled off Francois Steyn specials from 60m out. All just at the local park so not under pressure, but it is definitely a major factor. I think Morne Steyn is a good example of this. His style is not super reliant on a big run up or a massive follow through but he kicks like a monster. Chris Latham is one that works against my rule though haha. He used to smash the hell out of them! But I'd say thats a rare combination of power and timing :)
 
RoffsChoice

RoffsChoice

Jim Lenehan (48)
Kicking distance is entirely related to leg length, the speed at which the leg goes from the top of the arc to the ball and the mass of the leg. Leg length is the one that you can't improve through training, while leg mass and speed of arc can be improved. Leg mass will only have half the impact of leg length or arc speed, but is arguably the easiest to improve.

Answer gravy

It's a torque to force problem, but much easier to solve with energy.
m is the mass of the leg, w is angular velocity (aka how much of a circle something completes per second), v is velocity and r is lever distance (leg length).
v = WR (World Rugby)
The energy the ball can get is 1/2 m(v^2), mass of the ball doesn't change
So if all the energy of the leg goes into the ball, it is equal to 1/2 m (WR (World Rugby))^2.

Putting some values in:
Average leg mass is 20kg, Average leg length is 0.9m and the average kicker goes 1/8th of a circle in 1.5s.
so energy is about 13.3J. That will give the ball, at most, a total velocity of 64.9m/s.

To get the max distance, you want a 45 degree angle, so that gives it a horizontal and vertical velocity of 45.9m/s.
To get the time it takes to get to the peak height, you use v = u + at and let v = 0
so the initial vertical velocity = 45.9m/s, the vertical acceleration = -9.8m/s/s.
So t = -u/a = 4.68 seconds, and due to it being a parabola, the total time is 9.36s.
That means the ball can go 429m.

Yeah, as if. So the problem was the assumption that all the energy went into the ball.

An average kicker is Jayson Hayward, if we were inspecting him he would have these sorts of values and yet can only really kick it about 40m. So only 1/10th of the energy goes into the ball from an average kicker.

Reading through this shows the conclusions reached above.
 
Pfitzy

Pfitzy

George Gregan (70)
There is also an ideal contact point i.e. the "sweet spot" - being able to hit this consistently with the right surface area of the foot is important. If the total energy from the leg is driven into the most efficient area of the ball, then the transfer of energy is more effective.

It can be taught - kids who play AFL from an early age will quite often be better kickers from hand than a lot of rugby juniors. In part its because they're kicking a ball more designed for it (and slightly smaller), but mostly because kicking is the skill the game is based upon.

Though interestingly, I was talking to a guy who played some minor grade Aussie Rules in Melbourne after he'd moved to Sydney. He said the game up here was much more about long kicking because conditions were better in winter (less rain) while the more competitive Melbourne comp relied on short passing and accuracy due to the higher level of talent and competitiveness at the mark.
 
RoffsChoice

RoffsChoice

Jim Lenehan (48)
That is part of the calculations I used above, but I just assumed the kicker was kicking it dead on.
kick.png

So the blue is the ball with the different lines being different angles of striking the ball.
Work is really done using FsCos(x). So the green line is x = 0, which means the work applied along the y axis is equal to the work put in on the angle.
However, with the orange line, x = pi/3, so the work applied along the y axis is half the work applied at the angle, and with the red line x = pi/2, so the work applied along the y axis is 0.

So the sweet spot is getting the angle between the kick and the y axis to be 0.
 
Scoey

Scoey

Tony Shaw (54)
Rod Kafer has always said it has something to do with size of the kickers "seat". He describes Nic White as being a guy (much like himself) with an "ample seat" and this assists with kicking distance. I don't see how it can, but he's said it a few times.​
 
USARugger

USARugger

John Thornett (49)
You mean a big ass?

Having a good amount of muscle mass and decent proportion of fast-twitch fibers in and around the hip area is a big factor in leg speed which is a major factor in kicking power.
 
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