So, first day out I figured I may as well throw on some armor. I am glad I did, local hill was glare ice. Took about five good jabs to get a ski pole to bust through. Wasn't about to head home so I gave it a go for a few runs. I didn't take any serious shots but I tried a few simulated knee drops just to see how they would fare. They are made up of a foam that gets more rigid the higher the impact and from what I put them through they worked really well and should hold up to anything I could conceive happening in them. The nicest part about them is the construction. It is the soft pads laid over a lycra sleeve. Not bulky and I didn't even know I was wearing them after a few minutes. Quite breathable too, I can see using them for biking and skating come spring & summer.