(Updated June 8, 2016)
Except for the off-trail mountaineers among us, the old 10 lb. hiking boots have fallen out of favor. With research1 finding that weight2 on your feet requires approx 5x the energy3 to move as weight carried elsewhere, there’s good reason to lighten our foot load.
My “go to” hiking shoes, when it’s not cold or wet, have been New Balance Minimus trail running shoes. A pair weighs less than 6 oz, and with all the mesh they breathe incredible well. I actually own two pair: one in garishly neon blue, and another in glow-in-the-dark white (style is the last refuge of the incompetent).
Although I normally wear a size 11.5, and that works fine for day hiking with a lighter pack, I think it’s too small for backpacking. Being on your feet all day, and carrying more weight, makes your feet both swell and “pancake” (flatten out). My right big toe was numb for weeks afterwards, from being pressed inside my shoe. Although most people recommend you get a “good” fitting shoe (because having your feet slide around in your shoes is a good way to get blisters) I think I’ll risk a 12, 12.5 or 12W next time.
I had no problems with stability, “rolling” an ankle, etc. Of course, I wasn’t carrying an overwhelming amount of weight (30lbs), and I’ve never had any trouble with my ankles anyway, so your mileage may vary. Still, I personally am firmly in the camp of those who say that big boots with thick soles that lace up practically to your knees are actually worse for your ankles: the make your ankles weaker by not allowing you to exercise them, and the thicker soles and tread make it so that if you do roll an ankle, the displacement will be much greater than with a more minimal shoe, making it that much more likely that you’ll sustain a real injury.
That said, the Minimuses (Minimusi?) had two main disadvantages when it comes to backpacking:
The tread does not have much grip at all. I would be hesitant to wear them on any kind of slick or wet rock, and they were pretty unstable the few times I had to wade across streams in them.
The pair I wore got pretty torn up over the three days I was on them. They have since been relegated to lawn-mowing shoes. The tread is worn down and torn in several places, and, being white, the dirty stains are pretty much permanent. I would not trust them to hold up over a longer trip.
One nice thing about the Minimus is that they can be worn fairly comfortably without socks (I wore them with a pair of liner socks), and they are easy to slip on. This makes it practical to put them on in the middle of the night (glow-in-the-dark!) to answer the call of the wild without undue effort.
For a later trip, I tried a pair of La Sportiva Ultra Raptor trail runners, but found them unwearably painful. Although they are known to run a size small, and I purchased them a size larger than normal, they were still incredibly tight, especially in the heel. After wearing them around the house for about an hour, my feet were numb. They also have plastic projections on the roof of the shoe that dug into my skin.
The energy cost and heart-rate response of trained and untrained subjects walking and running in shoes and boots Bruce H. Jones, Michael M. Toner, William L. Daniels, Joseph J. Knapik, Ergonomics, vol. 27, iss. 8, 1984 ↩
Physiological strain due to load carrying in heavy footwear M. Holewijn, R. Hens, L. J. A. Wammes ↩