The Alpinestars Morzine knee pads are lightweight, with two thin Velcro straps to secure them but no sleeve to keep them in place or stop them rotating around your legs.
There's a fair amount of soft padding that covers the knee well for direct impacts, but the two basic straps simply don’t hold them on your leg well enough to truly protect. The pads also bunch up, even when they’re uncomfortably tight, and they can easily rotate without you wanting them to, which isn't good in a crash.
Considering the current competition and how good most pads are these days, this isn’t what we expect from a company with a high-end pedigree like Alpinestars. We wouldn’t even see a benefit to using these pads on a cross-country ride, because the protection they might add if they stayed in place during a crash is undermined by the poor fit.
Alpinestars Morzine 2012
Alpinestars seem to be aware of the issues with the 2011 Morzines and have corrected them for 2012. Using a full sock design, the updated pads now fit securely, don't move and are comfortable for all-day use. We've already ridden 45 miles wearing them and are impressed – look out for a review in Mountain Biking UK and on BikeRadar soon.

Alpinestars' 2012 Morzine pads look to be a big improvement on the originals
This article was originally published in Mountain Biking UK magazine.