Resources

Load Leg

Posted in: Glossary, Rear-Facing Seats

Key Info about Load Legs:

A load leg – sometimes called a foot prop or support leg – is a metal support leg that comes down from the edge of the rear-facing car seat’s base and rests on the floor of the vehicle

Crash tests show that this significantly reduces the forces on the baby’s head and neck – thereby keeping your baby’s brain and spine safer

Found commonly in Europe, but only offered on a few US seats

Seats in the US currently featuring load legs:

Clek Liing (coming in early 2019)

Cybex Aton2, AtonMAtonQ, and CloudQ

GB Asana 35 AP

Nuna Pipa

Peg Perego Primo Viaggio 4-35 Nido

Screen Shot 2015-11-16 at 11.32.07 AM

Cybex Aton2 & Nuna Pipa shown in image above

Why should you want a car seat with a load leg? What does it do and how does it work?

Reduces downward rotation:

Screen Shot 2015-12-21 at 4.53.29 PMThe goal of a car seat is to decrease the forces on a child’s body. The back of a rear-facing car seat should absorb the crash forces and the remaining forces should be applied onto the strongest part of the child’s body — their back. The load leg allows the car seat to do this better. In a frontal crash, a rear-facing child – and their rear-facing car seat – will move towards the front of the vehicle. In addition to moving forwards, the car seat will also rotate downwards (i.e. become more reclined) as the vehicle’s seat cushion compresses. The more reclined the car seat becomes during the crash, the more the child slides up the car seat. When a child slides up the car seat, forces are applied to the child’s neck and shoulders. A load leg works by preventing the car seat from going any more reclined during a crash, which therefore reduces how much the child will slide up the car seat. In so doing, more of the crash forces can be absorbed by the back of the car seat and distributed along the child’s back, rather than into the child’s neck and shoulders. Crash tests of the same car seat with and without the use of the load leg show that using the load leg significantly reduces head injury criteria (HIC).

Limits rebound:

Load legs also serve as anti-rebound devices in frontal crashes. Rebound is the movement of the car seat towards the back of the vehicle in a frontal crash. Anti-rebound devices limit how far the rear-facing car seat can move towards the back of the vehicle – which can prevent the child’s head from contacting the back of the vehicle seat during a crash.

How does a load leg limit rebound? Imagine jumping on a trampoline. For every action there is an equal and opposite reaction. If you take a big jump on a trampoline, you’ll bounce really high up. If you take a tiny jump, you’ll barely bounce up at all. The jump is your action, and the bounce is your reaction – also called rebound. How does this relate to a rear-facing car seat in a frontal crash? Most rear-facing only seats will rotate downwards a fair amount during a frontal crash (like a big jump on a trampoline) and then will rebound towards the back of the vehicle a lot thereafter (like the high bounce you get from that big jump). However, on a rear-facing seat with a load leg, there is basically no downward rotation (no jump) and therefore there is very little rebound as a result.

This video below shows how a load leg both decreases how far the car seat rotates downward (as shown by the red line) and how far the car seat rebounds (as shown by the blue line). The green line is there to show the recline angle of the car seats before the crash – and you can see it is identical on both seats. These crash tests are of the exact same Cybex Aton2 with the only difference being that the one on the left did NOT use the load leg and the one on the right did.

Please note that the motion seen in the seat without the load leg is typical of other manufacturer’s infant seats without a load leg.

How should you position the load leg?

A load leg should rest on the floor of the vehicle and should allow the base to rest flush on the vehicle seat, meaning the base should not be elevated off the seat cushion. The load leg should not push the base upright or be used to achieve the correct recline angle for a newborn.

Will the load leg fit in my vehicle? What if it does not?

There are some vehicle features that may preclude you from using a load leg. Since the load leg is not a required feature on US seats (even though it is an added safety feature), if it doesn’t fit with your vehicle design, you can still install the base in that seating position, just with the load leg tucked under the base into its storage compartment. Your other option would be to move the base to another location in your vehicle to see if the load leg would fit better there.

Which vehicle features may prevent you from using the load leg?

Many sedans and some SUV’s have a “hump” on the floor in the center seat, where the center floor is raised up. In vehicles with “humps,” depending on how high the hump is and which car seat you have, the load leg may not fit in that position because the hump is too high and the base would be jacked up off the vehicle seat cushion, often making the baby sit much more upright than is allowed. For Cybex and GB, the front of the base (the part closest to the front of the vehicle) must still make contact with the vehicle seat cushion when using the load leg. For Nuna, if you are using rigid LATCH to install the base, the front end of the base does NOT have to contact the vehicle seat cushion when using the load leg (so long as the base is properly reclined).

Below are statements from Cybex, GB and Nuna affirming that they allow the use of the load leg in cases where there is a hump in the floor.

From Cybex & GB: “It is acceptable to use the Cybex and GB load leg in the center seat even if there is a hump.”(Michael Eppler, Head of Product Management Child Safety for Cybex)
 
From Nuna: The NUNA Pipa Stability leg can be used on all vehicle floors including the center where a hump is present if the leg fits correctly. The current limitation to the leg feature is in a seating location where a “stow and go” seat or storage area is located beneath the the floor of that seating position as this flooring is in actually a door that cannot handle the forces of the leg in a frontal crash. Crash testing has shown that these doors are not solid fixtures and cannot be used. All other seating positions are acceptable if the leg can be extended correctly and touch the floor, turning the indicator green. (Bob Wall, Nuna Global Advocate, CPST-I)

Some vehicles, like Chrysler and Dodge minivans with Stow N’ Go seats, have hollow floors–and the load leg requires a solid floor, so the load leg may NOT be used in these minivans in the 2nd row locations featuring Stow N’ Go seats.

Some outboard (side) seats may not accommodate load legs if the vehicle seat is very deep – as the load leg may not bend properly over the edge of the vehicle seat.

Consumer Reports Infant Seat Ratings & Load Legs

While its no secret that we don’t always agree with Consumer Reports, we are in 100% agreement that load legs are a key safety feature. When we met with them 2 years ago we asked them to separate out their crash test ratings from the overall score they assign a car seat – as crash test performance is objective, while the evaluation that goes into the overall score involves many subjective assessments of the seat. We also asked them to test more seats that offer a load leg and highlight to readers if the seat performed better with the load leg (knowing full well that every seat performs better with a load leg). And we are pleased to say that both changes are reflected in their new infant seat ratings.

In their August 2016 Infant Seat ratings, 4 out of the 6 seats that earned a “best” in their crash protection rating were those that featured a load leg (listed alphabetically below).

We’ve bolded the 2 that we recommend most highly.

Traveling without the base – i.e. with just the carrier – and want the same safety benefits that the load leg offers?

Of course you do! You’ll want an infant carrier that offers a European belt path for installing the carrier without the base. The hallmark of the European belt path is that the shoulder belt wraps around the back of the carrier – which functions in a crash exactly like a load leg by eliminating any downward rotation of the carrier and in so doing decreasing the forces on the child’s neck. Don’t be fooled by the name – even though it is called a European belt path it is found on quite a few car seats sold in the US and is something you’ll want to use whether you are traveling in the US, Europe, or anywhere else in the world without the base.

The following US seats currently on the market feature a European belt path on the carrier:

When doing the European belt path, some seats belts may seem too short to wrap around – but almost all are truly long enough if you do the tipping trick shown in the video below.

Note: The tipping trick shown above does not work with the Cybex CloudQ, Doona, and Peg Perego 4-35/4-35 Nido as the lap belt routes through the carrier’s handle and prevents you from tipping the seat up. You’ll want to do the trick shown in the video below when installing one of these seats if the seat belt seems too short for the European belt path.

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