Load Legs—Foot Props—Stability Legs—Anti-Rebound Bars
Updated September 2022
Load legs were first introduced to Americans in 2004 by Britax on the Baby Safe, a short-lived rear-facing only seat popular in Europe, but we weren’t quite ready for it. It had an anti-rebound bar, rigid LATCH, and a load leg: things American consumers simply didn’t understand, or want to pay the hefty price tag for at the time. Today’s shoppers are more sophisticated and researching such features is second-nature now.
Let’s address why load legs—aka foot props or stability legs—exist. Here on this side of the Atlantic, we find them on rear-facing only infant seats and the new Cybex Sirona S convertible carseat, but in Europe, you will find them also on forward-facing carseats. Load legs limit downward rotation toward the front of the vehicle. Statistically, frontal crashes account for the majority of crashes so we design carseats to protect children in them. Carseats move toward the point of impact, so rear-facing carseats rotate down and toward the front of the vehicle in a frontal impact.
According to FMVSS 213, the safety standard to which all U.S. carseats are tested, rear-facing carseats may rotate downward up to 70° and still pass testing. During this downward rotation, the child will also ramp up (slide up) the carseat. As the child slides up the seat, crash forces are felt in the neck and shoulders as they make contact with the harness.
Harnesses, seat belts, and LATCH belt webbing are designed to stretch for energy management. This stretching of the webbing—plus any removal of slack in the harness—and vehicle seat cushion compression causing downward rotation, is called “payout.” Payout happens before ride down, which is when the carseat and vehicle come to a stop. The more movement a child has during a crash, the more chance for injury, which is why child passenger safety technicians emphasize snug harnesses and installations. Eliminating the downward rotation by using a load leg means the child stays down in the seat and payout is reduced. This is a good thing because the less time that’s spent on payout, the more time that’s spent on ride down, which is when the carseat itself starts absorbing energy. The carseat stays more upright allowing the back of the carseat to absorb energy instead of the harness; the crash forces are distributed along the child’s back instead of concentrated on the neck and shoulders.
Another benefit from load legs, especially in smaller vehicles, is that by allowing the carseat to stay more upright in a crash, there’s less of a chance a child will ramp up and out of the carseat and strike the vehicle interior with their head. Head injuries lead the list of injuries to rear-facing children in vehicle crashes.
The video below compares a Cybex Aton 2 without its load leg to an Aton 2 with its load leg. You can see how a load leg affects downward rotation. Be sure to notice the position of the dummy’s head on each side of the video.
Another thing to point out with load legs involves FMVSS 213 and testing with load legs. The test sled for 213 doesn’t have a floor, so load legs can’t officially be included in federal testing. Frustratingly enough, NHTSA won’t add a floor to the test sled to officially crash test load legs because it feels that caregivers won’t use the load leg feature. I wish we were kidding.
When manufacturers test their carseats with load legs, they add a floor piece onto the sled so the load leg has a place to rest and NHTSA allows this practice. It’s part of that “extra testing” that manufacturers do to their carseats that their marketing department then labels on the box. This is why load legs aren’t required to be used and bases with this accessory have a storage area for them to be tucked away.
What about Rebound?
We can’t really talk about load legs without discussing rebound. Rebound is the action of a rear-facing carseat when the top part of it moves toward the back seat upon pushing or collision. On a carseat without a load leg, after the downward rotation, there will be rebound (remember Newton’s 3rd Law: for every action, there is an equal and opposite reaction) into the vehicle seat back. All the energy that goes into stretching of webbing and vehicle seat compression has to have a place to go, hence rebound. Rebound with a typical rear-facing carseat usually has 1/3 the energy of the initial crash by the time the carseat impacts the vehicle seat. On a carseat with a load leg, since the downward motion is limited and that energy has been absorbed by the vehicle and the carseat, the rebound will be reduced.
Britax nicely explains rebound in this video (though note that the RF is 5 times safer has been found to be erroneous, but we do know RF to the limits of the carseat is safest).
You can also see rebound on a carseat that doesn’t have rebound control (either with a load leg or with an anti-rebound bar) below. Remember that crash tests look scary, but that as stated above, rebound has typically 1/3 the energy of the initial crash. While there have been injuries to legs on rebound, they have been relatively minor (compared to what can happen forward-facing) and very few. All rear-facing carseats without rebound control will look similar to this one.
On viewing the Clek Liing rear-facing only carseat crash test video below, you can see that the carrier moves slightly on the base, but the base doesn’t move due to installation with rigid LATCH and the load leg. Energy is transferred to the floor and Clek claims crash forces are reduced by more than 40%. Energy is released on rebound but is slight compared to a carseat lacking the load leg feature.
There are carseats, both rear-facing only infant seats and convertible seats, that have anti-rebound bars (ARBs); it’s a more common feature than the load leg. Anti-rebound capability is required in Canada, so Canadian carseats may have it built in to the structure versus having an ARB that must be attached rear-facing.
Alternatives to Using a Load Leg
One alternative to using a load leg on a rear-facing only carseat is installing the carrier without the base Euro-style. This requires that the carrier have a clip or other feature on the back of the seat allowing the shoulder belt to be routed behind the child’s head; not all seats allow this. Having the shoulder belt wrapped around behind the seat supports it and keeps it from rotating down.
Another is installing a convertible using a rear-facing tether Australian-style (Aussie-style). The tether wraps around the back of the carseat and attaches to the vehicle’s tether anchor. Clek has the Q-Tether for its Foonf and Fllo convertibles.
Things to Think about When Using a Load Leg:
- Load legs must firmly touch the floor, but not lift the base off the vehicle seat or alter the advised recline angle.
- Check that the load leg is locked into position. Most have a visual cue to help you determine if it’s locked correctly.
- Some vehicle seats may be too deep for the load leg to unfold naturally over the edge of the cushion. If that’s the case, store the load leg or use a different back seat position.
- Some center seats have a hump on the floor that makes it incompatible with fully extending the load leg. If that’s the case, store the load leg or use a different back seat position.
- Check your vehicle owner’s manual if you own a vehicle with in-floor storage areas. Some vehicles explicitly forbid the use of load legs over these storage areas.
For being around a long time, load legs are certainly starting to make a splash in the market here. As with any carseat, a base with a load leg may not work well in your vehicle or with other carseats in your car. Because of their reduction in crash forces, a carseat with a load leg is a feature worth considering if you can find one in your price range with other features you like and that you’ll use correctly each ride.
Carseats with Load Legs
Scroll → to see full table
|Model||Price||Rigid LATCH||CarseatBlog Review||CarseatBlog Recommended Seat|
|Cybex Aton 2||$229.95||No||Yes|
|Cybex Aton M||$399.95||No|
|Cybex Cloud Q||$399.95||No|
|Cybex Sirona S||$549.99||No|
|Evenflo LiteMax DLX||$224.99||No||Yes||Yes|
|Evenflo Gold SecureMax||$239.99||No|
|Graco Premier SnugRide SnugFit 35 XT||$349.99||No|
|Maxi-Cosi Coral XP||$399.99||No|
|Maxi-Cosi Mico XP Max||$319.99||No|
|Nuna PIPA/Stokke PIPA/Bug Turtle||$319.95||Yes||Yes||Yes|
|Nuna Pipa Lite||$349.95||Yes||Yes|
|Nuna Pipa Lite R||$349.95||Yes||Yes|
|Nuna Pipa Lite LX||$399.95||Yes|
|Nuna Pipa Lite RX||$349.95||Yes|
|Nuna Pipa RX||$309.95||Yes||Yes|
|Peg Perego Primo Viaggio 4-35 Lounge||$429.99||No|
|Peg Perego Primo Viaggio 4-35 Nido||$349.99||No||Yes|
|Model||Price||Rigid LATCH||CarseatBlog Review||CarseatBlog Recommended Seat|
Hi, can you do a review of the clek liing and the new Nuna RX + RELX base. The Nuna has a load leg and antirebound bar. Does it make it safer than the clek liing? Is it the only infant seat to have both?
Hi Jessica. It’s hard to say if an anti-rebound bar makes a carseat “safer” because there are so many variables that go into that word. A load leg transfers most of the energy to the vehicle floor, so does it really matter if a carseat doesn’t have an ARB? No one has done a study on it yet, so we don’t know. What we think matters most is installation with rigid LATCH and the load leg; an ARB is icing on the cake.
AFAIK, the RELX base is the only base to have both ARB and a load leg. We are working on a review of the RX with RELX base, but I can’t give a timeframe on its completion since I’m not the one writing it.
We just purchased the Nuna Pipa and noticed that when taking the infant seat off the base it’s really easy to accidentally raise the leg and change the position of the base so it’s higher off the seat.
We’re then left with trusting everyone who drives our baby to check the install every time they take baby in and out or not using the leg. Have you heard any issues with this? Thoughts? Is it safer to have the leg imperfectly installed or not even used?
Hi Jessica. This is something that happens with the Pipa. Nuna claims that they’ve made it harder for the leg to adjust itself when lifting the infant seat off, but it can still be frustrating if you don’t lift just right. I’d suggest calling and complaining and hitting their social media sites as well. You may want to teach those who drive your baby to lift the seat straight up so it doesn’t get caught and cause the leg to drop.
For caregivers, you may want to show them how to adjust the leg just in case it gets over-adjusted to the point that it’s at a crazy recline angle. Depending on how old your child is, having it up a click may not matter.
I am looking for convertible carsears with a load leg and ARB, so far I can only find 2 infant seats with both. Have you seen any convertible ones?
Peg Perego Primo Viaggio NIDO $350
Cybex Aton M Sensorsafe $350
Hi Velma. The Cybex Sirona S, which hasn’t been released yet (https://carseatblog.com/47513/cybex-sirona-s-convertible-car-seat-with-load-leg/), will be the only convertible in the US with a load leg. There are quite a few with ARBs (Britax, Clek, Peg Perego), but it’s very difficult to bring load legs to convertibles because of the testing sled.
The question I’ve had for a while is what to do if there is only one child and the car has a center hump on the floor. Usually I would put that child in the center seat. With a load leg, that child would need to be placed outboard, i.e. in a position not thought to be as safe. Thoughts?
Some load legs are short enough that you can still use them, like the GB Asana35 DLX, though sometimes the humps are still too tall. Load legs can help stabilize a RF seat in a side impact, so even if you’re struck on the side, they can still provide a measure of help in a crash. If the seat you own also has rigid LATCH as a method of installation and you don’t have a dedicated LATCH position in the center, I think you’re probably better off installing the seat on the side so you can take advantage of the added safety features of the rigid LATCH and the load leg. The less energy that the child absorbs in a crash translates to less chance of injury, so the less the carseat moves, the less energy there will be.
Of course, you hope not to be hit near side if you put the carseat on the side too, but you can’t pick your crashes. We play by statistics in child passenger safety and statistically, the most common type of crash is the frontal crash so that’s what we plan for.
Maxi Cosi Mico Max Plus has a base with a load leg as well.
Yes, thanks, Jenifer! I’ll update the list.