I have to weigh-in with Lori. I have hiked off-trail in the Sierra for over 10 years in tennis shoes and low-cut hikers. The terrrain inclueds 80% of the Sierra High Route and LOTS of talus hopping. Occasionally on scree, I have to go slower than I would if I had mountaineering boots. But I would rather slow down 5% of the time and be lighter the other 95%. I have even strapped crampons on tennis shoes. My toes got a bit chilly after 2 hours in snow. I replace the insole with Superfeet and size for thick wool socks. I ditched the boots 15 years ago. My shoe of choice is now a Merrel low-cut leather shoe.

I think it is all individual. I am light, carry a moderately light pack and have strong ankles. I do feel that repeated use of low-cut shoes has strengthened my ankles. For those with a history of serious ankle injury, this probably will not work.

But I do think you need to experiment and go with the lightest shoe that works for you. You may want to try a mid-cut shoe. Be sure to get a boot or shoe that really fits well. I think it all helps - even how the arch fits or having the proper width on the fore-foot.