Back protectors got to be tight to work. This totally flys in the face of the need for extreme mobility in freestyle sports including big mountain skiing.
Most of the "vest" or "jacket" ones that are any good, have velcro straps anyway. My son Jasper used a POC VPD 2.0 sm/x-sm for big mountain skiing and freeskiing. I started to notice him leaving it in the car during comps & called him out on it. He even cut off the sleeves. Apparently, if it's tight enough that the plate/pad won't move in a crash, it's then too tight to allow "extreme" mobility. This may be less of an issue in Alpine Racing.
Jasper has since switched to "Pro tech" shirts & pants with the VPD pads built into the clothing. These looser fitting pads still provide good protection on first impacts, but tend to move and become less effective in multi-impact crashes. It's going to be a compromise either way. Better protection vs. mobility. Sometimes the pads save you completely. Sometimes a rock will go right through armor like it wasn't even there.
I just torched a $200 Bell Full-Face Mt. Bike Helmet, Full-armor Fox Knee/Shin pads & a pair of shades in a mt. bike crash at Crested Butte. A rock still got through my helmet, smashing my shades, & a sharp rock got through my kneecap, just missing the armor plate, & cutting through the reinforced padding like butter. If I had the velcro strap tight enough to stay in place completely in a big crash, it would be too tight to peddle. You gotta compromise. Still, I'd probably be getting thrown in the trash instead of my equipment if I didn't have it, tight or loose
. I would recommend the lightest, loosest fitting pads you can get. If FIS is picking the list of acceptable models, the one with the least amount of protection will still probably be highly rated & extremely uncomfortable for freestyle sports.
Sometimes, lack of mobility can cause you to crash just as bad or worse than if you didn't even have the armor.
If you know any "little" racers needing a back/chest protector, we have a POC VPD 2.0 sm/x-sm for sale super cheap. Good luck. I hope FIS picks a wide variety of armor that fits well for everyone.
I'll be very interested to see where they go with this. FIS is starting to get heavily involved in safety issues in Freeskiing/Snowboarding too, now that pro freestyle sports are falling under FIS rules more and more. What they do in Alpine tends to bleed over into other disciplines eventually.