# Rebounding or cocooning of RF seat...



## JoyofBirth (Mar 16, 2004)

Is there anything in the way of safety tests or reports or similar that talk about rebounding or cocooning of Rear-facing seats? I've heard lots of opinions on the subject and have my on opinions on it. We do not have the option of using a carseat with an anti-rebound bar, so I would like to know if it's really okay and for how long, etc. Thank you anybody who cn point me in the right direction.


----------



## an_aurora (Jun 2, 2006)

This is a short quote about coccooning from the CPST encylopedia:

Quote:

The first U.S. infant restraint, which is the model for subsequent ones, did not use a tether in either direction nor a shoulder belt, but it worked very well. During development, the engineers observed that it turned over toward the vehicle seatback after a crash test and, largely in order to justify what happened anyway, they called this the "cocoon effect." There was also some justifiable concern that the small infant's neck might be injured on rebound or rear-impact unless the restraint were allowed to freely rotate in this direction. Justified or not, this concept has remained and seems to make intuitive sense. The counter-argument that the infant's head will "slam" into the seatback and be injured on rebound has not been validated in over 30 years of crash experience.


----------



## riversong (Aug 11, 2005)

I'm confused. What's an anti-rebound bar?

Is the OP concerned about her baby hitting the back of the seat the car seat is installed in during a crash?


----------



## an_aurora (Jun 2, 2006)

Quote:


Originally Posted by *riversong* 
I'm confused. What's an anti-rebound bar?

Is the OP concerned about her baby hitting the back of the seat the car seat is installed in during a crash?

The ARB is just that, a bar designed to reduce rebound. The Combi Shuttle and Britax Companion infant seats have them, and the True Fit is coming out in January with it.


----------



## Pumpkin_Pie (Oct 10, 2006)

Quote:


Originally Posted by *an_aurora* 
This is a short quote about coccooning from the CPST encylopedia:

So, am I reading this right that there is no evidence that a rebound bar helps in any way?


----------



## an_aurora (Jun 2, 2006)

Quote:


Originally Posted by *Pumpkin_Pie* 
So, am I reading this right that there is no evidence that a rebound bar helps in any way?

Well, no that's not what it's saying. The ARB does reduce rebound, there's just no real evidence saying rebound is dangerous.


----------



## Pumpkin_Pie (Oct 10, 2006)

Ah, thanks. Is there any anecdotal evidence that having a rebound bar is safer?


----------



## an_aurora (Jun 2, 2006)

Quote:


Originally Posted by *Pumpkin_Pie* 
Ah, thanks. Is there any anecdotal evidence that having a rebound bar is safer?

Not that we know of, no, but some carseat manufacturers believe it's important--Britax and Sunshine kids recommend the RF tether, which accomplishes the same thing. Compass/Learning Curve/First Years is against RF tethering but is coming out with the ARB. So they must believe it's beneficial.


----------



## riversong (Aug 11, 2005)

Thanks for the pictures. Why is compass/learning curve/first years against rf tethering?


----------



## an_aurora (Jun 2, 2006)

Quote:


Originally Posted by *riversong* 
Thanks for the pictures. Why is compass/learning curve/first years against rf tethering?

They just don't think it's safe. There are some techs that are against RF tethering because it can increase neck loads. Others swear by it. It's really a matter of opinion. I just think it's weird that Compass is against RF tethering but is coming out with the ARB. I am excited though


----------



## Smalls181 (May 12, 2006)

Sweden tethers RF, dont they? Or is it more of a foot braced on the floor? Either way, it prevents the rebounding, and their child safety record is impeccable, to say the least.


----------



## mcng (Oct 17, 2006)

From what I read I would not tether a seat for a infant under the age of one, when the seat moves it absorbs some of the crash forces, if the seat is static the baby absorbs those forces and beeing the head the heaviest part of the body that its unrestrained it will be thrown forward causing more stress on the babys neck.


----------



## an_aurora (Jun 2, 2006)

Quote:


Originally Posted by *Smalls181* 
Sweden tethers RF, dont they? Or is it more of a foot braced on the floor? Either way, it prevents the rebounding, and their child safety record is impeccable, to say the least.

No, they have the little foot prop and some have an ARB, but the foot prop prevents over-rotation, which is movement in the other direction (towards the floor) due to the heavy child.


----------



## an_aurora (Jun 2, 2006)

Quote:


Originally Posted by *mcng* 
From what I read I would not tether a seat for a infant under the age of one, when the seat moves it absorbs some of the crash forces, if the seat is static the baby absorbs those forces and beeing the head the heaviest part of the body that its unrestrained it will be thrown forward causing more stress on the babys neck.

Yep, that is the argument against RF tethering


----------



## tempestjewel (Apr 18, 2005)

What about slack versus tight RF tethering? If the RF tether has some slack in it (not pulled tight) will that allow enough energy absorption/movement in a crash?

And, the anti-rebound bar, does it allow it to rebound to a certain point and just not all the way?

Just trying to make sense of this


----------



## an_aurora (Jun 2, 2006)

Quote:


Originally Posted by *tempestjewel* 
What about slack versus tight RF tethering? If the RF tether has some slack in it (not pulled tight) will that allow enough energy absorption/movement in a crash?

And, the anti-rebound bar, does it allow it to rebound to a certain point and just not all the way?

Just trying to make sense of this









No, loose RF tethering would just allow movemewnt and then jerk it to a stop.

And yes, the ARB just reduces the amount of rebound, but doesn't totally prevent it.


----------



## tempestjewel (Apr 18, 2005)

Quote:


Originally Posted by *an_aurora* 
No, loose RF tethering would just allow movemewnt and then jerk it to a stop.

And yes, the ARB just reduces the amount of rebound, but doesn't totally prevent it.

Ok, so the ARB sounds like it'd do a better job of preventing rebound without the big jolt of a RF tether?

When I read the CPST manual linked above it said tethering was most likely worthwhile for large/older children where they risk rebounding hard into something hard in the car because of their increased weight. My youngest DD is 25 pounds and almost 2 so I'm wondering if the RF tether would be worth it for her or not.


----------



## an_aurora (Jun 2, 2006)

Quote:


Originally Posted by *tempestjewel* 
Ok, so the ARB sounds like it'd do a better job of preventing rebound without the big jolt of a RF tether?

When I read the CPST manual linked above it said tethering was most likely worthwhile for large/older children where they risk rebounding hard into something hard in the car because of their increased weight. My youngest DD is 25 pounds and almost 2 so I'm wondering if the RF tether would be worth it for her or not.

From what I have heard/read, the RF tether does a great job in side-impact crashes since it stabilizes the top of the child restraint (thus limiting the amount of movement of the child's head, preventing head impact). So that would be one situation in which a RF tether would be more beneficial than an ARB. However, it seems like the ARB is more beneficial for younger infants.

I am familiar with both arguements and I am comfortable tethering my RF infant's Marathon, and now that she is a RF toddler she is still tethered. However, I don't think that cocooning/rebound is a catastrophic event, and the design of modern carseats provide protection for the child's head. I wouldn't _only_ buy a seat with a RF tether.


----------



## tempestjewel (Apr 18, 2005)

Quote:


Originally Posted by *an_aurora* 
From what I have heard/read, the RF tether does a great job in side-impact crashes since it stabilizes the top of the child restraint (thus limiting the amount of movement of the child's head, preventing head impact). So that would be one situation in which a RF tether would be more beneficial than an ARB. However, it seems like the ARB is more beneficial for younger infants.

I am familiar with both arguements and I am comfortable tethering my RF infant's Marathon, and now that she is a RF toddler she is still tethered. However, I don't think that cocooning/rebound is a catastrophic event, and the design of modern carseats provide protection for the child's head. I wouldn't _only_ buy a seat with a RF tether.

Thank you for your answer- I did a bit more reading too and it seems like it'd not place my youngest DD at much risk to RF tether her. I have to replace a seat soon and was planning on getting a Radian because I need skinny seats in the back of my Toyota Corolla, so I'm learning more about cons of RF tethering- I'd not heard of the concerns before!


----------



## Smalls181 (May 12, 2006)

Quote:


Originally Posted by *an_aurora* 
From what I have heard/read, the RF tether does a great job in side-impact crashes since it stabilizes the top of the child restraint (thus limiting the amount of movement of the child's head, preventing head impact). So that would be one situation in which a RF tether would be more beneficial than an ARB. However, it seems like the ARB is more beneficial for younger infants.

I am familiar with both arguements and I am comfortable tethering my RF infant's Marathon, and now that she is a RF toddler she is still tethered. However, I don't think that cocooning/rebound is a catastrophic event, and the design of modern carseats provide protection for the child's head. I wouldn't _only_ buy a seat with a RF tether.

I cannot decide which one I prefer for my DD. I see the pro's and cons to both. I am leaning more towards a Britax than a TF because my gut tells me tethering is better. But then I also add in the fact that with a TF, she can RF significantly longer than in a Marathon, due to the height of the shell. So what I am wrestling with is do I RF longer with an ARB instead of a tether, or RF for a shorter time with a tether? With DD, we are looking at probably RF to 4-4.5 in a Marathon, or 5-5.5 in a TF. She is pretty petite, long legs, shorter torso.

Honestly, I wish that TF will approve the RF tether and let the parents decide which option they are more comfortable with.


----------



## alegna (Jan 14, 2003)

Quote:


Originally Posted by *Smalls181* 
I cannot decide which one I prefer for my DD. I see the pro's and cons to both. I am leaning more towards a Britax than a TF because my gut tells me tethering is better. But then I also add in the fact that with a TF, she can RF significantly longer than in a Marathon, due to the height of the shell. So what I am wrestling with is do I RF longer with an ARB instead of a tether, or RF for a shorter time with a tether? With DD, we are looking at probably RF to 4-4.5 in a Marathon, or 5-5.5 in a TF. She is pretty petite, long legs, shorter torso.

Honestly, I wish that TF will approve the RF tether and let the parents decide which option they are more comfortable with.

From my reading it is really pretty rare to have a kid outgrow a marathon rf by height before weight.

-Angela


----------



## an_aurora (Jun 2, 2006)

Quote:


Originally Posted by *alegna* 
From my reading it is really pretty rare to have a kid outgrow a marathon rf by height before weight.

-Angela

Not really. :nana: I know of several.


----------



## alegna (Jan 14, 2003)

Quote:


Originally Posted by *an_aurora* 
Not really. :nana: I know of several.

Yeah, yours are the ones I've heard of









But it occurs to me that it will be more likely now with the 35lb weight limit.

-Angela


----------



## an_aurora (Jun 2, 2006)

Lol. There are several on c-s.org, and I know of 2 IRL (besides mine).


----------



## Smalls181 (May 12, 2006)

My sis has Marathons and Radians for her girls. Her almost 4 year old seems to be on a similar growth curve as my dd, so I asked her to check her DD's height in that seat. She hasn't gotten back to me yet...


----------

