Downhill ski-boots are truly supportive for your ankles, which is proven by the fact that the leg usually snaps above the boot in accidents. They are also truly something you do not want to hike in.
Luckily there are lots of lighter solutions for people needing ankle support. The lighter your pack, the less need there is of ankle support. I have found that, unless you have injured an ankle, there is no need for ankle support with a light pack, no matter how demanding terrain you travel in. But if you need ankle support, or believe that you do, here are examples of some true ankle supports that do not weigh very much. They also have the advantage that you can use them on only one foot, if you only have one weak or injured ankle. Note that the photos only show examples picked from various websites. I have not used them myself since I have not needed them and see no need for other people to use them unless they have a medical condition. By the way, I am in no way associated with these companies.
|A bit sturdier are supports made by neoprene.
|With a brace like this you should have ample ankle support and still be able to walk. A lot lighter than a boot as well.
Comments and new insights:
Right now, barefoot running and walking are becoming hot in the outdoor industry. This means that many shoe manufacturers in 2011 will introduce lines of 'back to basic' shoes. Shoes that have thin soles and very little support. This strengthens me in my belief that boots simply are not necessary for backpacking. But more about that in the chapter Footwear.