Doctors on Helmets

KiteschoolHolland · **Posted:** Tue Apr 10, 2012 7:08 pm

davesails7 wrote:

KiteschoolHolland wrote:

davesails7 wrote:

Helmets don't absorb energy?

Who said that?
You should improve your reading and reasoning skills -
not the first time that I thought that.

Not trying to insult your intelligence. I mean you have to be a pretty smart guy if half of your head is 1.7 liters as you've told us :thumb:

I think your decision that helmets are more harmful than helpful for the majority of kiters is wrong. Every beginner has to make this decision, and some will make it based on information here. I'm pointing out where I think your reasoning is wrong so others can make an informed decision.

You avoid to answer my question:
Who said that?

And again you misquote me.
I don't decide what helmets are for others. Just for my self.

KiteschoolHolland · **Posted:** Tue Apr 10, 2012 7:25 pm

davesails7 wrote:

KiteschoolHolland wrote:

I measured the circumference of my head above the nose, without a helmet and with 3 brands kitehelmet: 59 cm, 64, 68 and 70.
If the water replacement on impact is calculated as a half sphere, it is 1,7 liters, 2.2, 2.6 and 2.9.

Water replacement? I'm guessing you're talking about the displaced volume of the helmet. I don't think displaced volume factors into it at all. Surface area does make a difference (belly flop vs. a dive), but the difference in surface area is pretty small.

Think again.
Your example exactly proves my point about the risk a helmet poses.
In water, you avoid the belly flop. You go for the dive. In order to lessen the impact.
If you approach a hard surface, like the ground, when falling from a tree, you go for the belly flop. Not the dive. You would break your neck because of the weight of your own body.
Wearing a helmet can increase the impact multifold as the water deplacement is increased by 40, or 60, or 80 %. I remember something like 1/2 m v squared equates impact. Simple physics.
I suppose it gets more complicated if the calculating also involves surface tension.

It needs more exact measuring and calculating, and I have pointed out from the start that the absorbing also comes into account, but I don't know how.

davesails7 · **Joined:** Sun Apr 01, 2007 7:36 pm **Posts:** 696

KiteschoolHolland wrote:

And again you misquote me.
I don't decide what helmets are for others. Just for my self.

When you post on this forum reasons not to wear a helmet you are influencing others to decide against helmets.

edt · **Posted:** Tue Apr 10, 2012 7:36 pm

KiteschoolHolland wrote:

In water, you avoid the belly flop. You go for the dive. In order to lessen the impact.

In a water crash landing you kick off your board, lean back and black flop or cannonball. If you dive head first, and it's too shallow you will break your neck, if you land feet first you will tear off your acl.

Kiters tear their ACLs all the time trying to land feet first. Better a deep water enema and sore balls than a torn ACL, that's what I say.

plummet · **Posted:** Wed Apr 11, 2012 8:19 am

this sums it up quite well

KiteschoolHolland · **Posted:** Wed Apr 11, 2012 10:51 am

edt wrote:

KiteschoolHolland wrote:

In water, you avoid the belly flop. You go for the dive. In order to lessen the impact.

In a water crash landing you kick off your board, lean back and black flop or cannonball. If you dive head first, and it's too shallow you will break your neck, if you land feet first you will tear off your acl.

Kiters tear their ACLs all the time trying to land feet first. Better a deep water enema and sore balls than a torn ACL, that's what I say.

Sure. I reacted to Dave's post about the dive vs bellyflop to illustrate the added impact on the neck. That's the context. In the case you describe, the kiter has a choice, and will always protect his head over either balls, ACL or feet.
You get the point: you can protect your neck by not enlarging the load that it gets in a crash.

alexrider · **Posted:** Wed Apr 11, 2012 10:59 am

plummet wrote:

this sums it up quite well
:lol:

alexrider · **Posted:** Wed Apr 11, 2012 11:05 am

Weather report for Netherlands:
Wind: 0 knots.

Weather report for Florida:
Wind: 0 knots.

KiteschoolHolland · **Posted:** Wed Apr 11, 2012 11:07 am

davesails7 wrote:

KiteschoolHolland wrote:

And again you misquote me.
I don't decide what helmets are for others. Just for my self.

When you post on this forum reasons not to wear a helmet you are influencing others to decide against helmets.

I'm searching for sound arguments.
Your misinformation doesn't help.
If the absorbing makes up for the extra load on the neck, I'll be happy to wear a helmet again.
The only Doctor on Helmets that I know of, decided against wearing one for himself and his son in an all-water kiteboarding lesson situation.
And he is not just any doctor, he is a traumatologist, the best of any type of doctor for this question (but we still miss scientifically researched information).
So if you cheaply dismiss his choice, it seems to me you're not fit for a discussion that will help beginners.

davesails7 · **Joined:** Sun Apr 01, 2007 7:36 pm **Posts:** 696

KiteschoolHolland wrote:

Wearing a helmet can increase the impact multifold as the water deplacement is increased by 40, or 60, or 80 %. I remember something like 1/2 m v squared equates impact. Simple physics.
I suppose it gets more complicated if the calculating also involves surface tension.

I seem to remember something about E = m*c^2 too. Don't know how to use it to prove my point though so I'll just post the equation and leave it at that so it looks like I used it to calculate the added force a helmet puts on my neck.

Alright, I'll stop spreading my misinformation here. I hope there is enough information for people to make an informed decision on whether a helmet does more harm than good.

Doctors on Helmets

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