Wallabies S and C coach

[hammertimethere]

agreed hence my comment that "size" on its own is irrelevant. Strength is definitely not

 

[Groucho]

agreed hence my comment that "size" on its own is irrelevant. Strength is definitely not

Size is relevant because it contributes to the energy in collisions. A 100 kg player moving at a given speed requires more effort from the opposing player to stop than a 90 kg player.

 

[hammertimethere]

Given that they move at the same speed, which is usually not the case. By energy you mean momentum, which equals mass x velocity.
e.g a kid wants to be a flanker but weights 94kg and has a maximum velocity of 8.7 m/s.
Momentum at top speed = 817.8 netwons

after eating and bodybuilding his way up to 98kg (a more appropriate weight) he has a max velocity of 7.9 m/s
Momentum at top speed = 774.2 Newtons

This is a crude example but it does support my earlier point. Size is all well and good if it comes with the strength relative to that bodyweight. If an 80kg back and a 110kg no 8 can both squat 2 x their bodyweight (160kg and 220kg) that is a pretty good indicator that their relative strength is similar. Extra muscle tissue might help prevent injury (maybe), but strength is what helps deal out the damage.

Besides by the time guys get to test level most of the players in the same position (in the forwards at least, not counting the Ma'afu's, Tameifuna's and Big Bill Cavubati's of the world ) are the same size give or take 10% at the most. Usually having it over your opponent physically is a function of how strong and aggressive you are, not how much you weigh. In the backs strength in absence of excess bodyweight (excess = what your frame can reasonably carry for 80 mins) can sometimes be advantageous (AAC (Adam Ashley-Cooper), Diggers, JO'C, Quade, GENIA to name a few) as strength = more potential to apply force to the ground when appropriately trained i.e run faster and stay on your feet during contact/keep arms free and a whole range of other good things.

Flesh is useless in the absence of strength

 

[fatprop]

agreed hence my comment that "size" on its own is irrelevant. Strength is definitely not

that is what they all say

 

[Hawko]

Size is relevant because it contributes to the energy in collisions. A 100 kg player moving at a given speed requires more effort from the opposing player to stop than a 90 kg player.

True if we translate it to a theoretical world where two objects collide. But there is so much more going on in the tackle situation that such analysis is insufficient to describe what is going on. If a player is taken down with a tackle around the chest it may be a rough approximation, but only rough. If its a tackle around the legs then the tackler is using the momentum of the runner to actually increase the force of the tackle. Thus, tackling someone around the legs who is standing still can be less effective than the same tackle on someone running. Reducing tackling to the theoretical two balls colliding takes out so much of the complexity that you will get bad answers if you apply it to practical rugby situations.

Why is Kieran Read the world's best number 8? He's not the biggest, the strongest or the fastest, but his strength and agility combine to make him the standout, whether he's got the ball or defending.

 

[Groucho]

True if we translate it to a theoretical world where two objects collide. But there is so much more going on in the tackle situation that such analysis is insufficient to describe what is going on. If a player is taken down with a tackle around the chest it may be a rough approximation, but only rough. If its a tackle around the legs then the tackler is using the momentum of the runner to actually increase the force of the tackle. Thus, tackling someone around the legs who is standing still can be less effective than the same tackle on someone running. Reducing tackling to the theoretical two balls colliding takes out so much of the complexity that you will get bad answers if you apply it to practical rugby situations.

Why is Kieran Read the world's best number 8? He's not the biggest, the strongest or the fastest, but his strength and agility combine to make him the standout, whether he's got the ball or defending.

I didn't mean to imply that size was the only consideration, only that it is relevant. Having said that, in many situations it is highly relevant. Many collisions in professional rugby are quite direct.

 

[Roundawhile]

Whilst I agree that muscle activation speed is a huge determinant, I believe that there should be a bit more consideration given to tendon/ligament development.

I wonder if the number of injuries in this area is because of an over-emphasis on muscle conditioning at the expense of the connectors?

 

[dangerousdave]

Whilst I agree that muscle activation speed is a huge determinant, I believe that there should be a bit more consideration given to tendon/ligament development.

I wonder if the number of injuries in this area is because of an over-emphasis on muscle conditioning at the expense of the connectors?

Lachie Turner's injury where he pulled his hamstring off the bone to me smacks of somebody who already had strong hamstrings (because he has always been fast as hell) spending too much time on the leg curl machine to rehab his hamstrings but who hasn't spent enough time over his career loading his body with heavy weights (eg. Farmers carries, deadlifts, squats etc.) to develop joint and tendon strength.