This may be painfully obvious to everyone but me, but it turns out that running shoes are terrible for exercises emphasizing lateral movement. Running shoes are engineered specifically for running (duh!); they're super-flexible up front, and sport thicker heels and soles to better cushion runners' heel-to-toe footfalls. Cross trainers, on the other hand, are the utility infielder of the athletic shoe world. They're built to be versatile, with outsoles designed for use in a number of sports and activities. To boost lateral stability, cross trainers feature soles and heels that are wider and sit lower to the ground. They also have a roomier (but stiffer) toe box.
I was sold, but needed advice on the best pair of cross trainers for my overpronating feet. Unbelievably, however, this information is incredibly difficult to dig up. Specialty running stores are fantastic when it comes to personalized guidance about selecting the right pair of running shoes, but most don't carry cross trainers, and will just recommend that you purchase a pair of tennis shoes for some lateral support. Numerous websites and magazines dissect running shoes in excessive detail; their reviews helpfully categorize each shoe for those with specific wants and needs (endurance! speed! overpronation! underpronation! motion control! cushioning! stability!). But cross trainers get no such love.
New Balance MX1210s and MX840s -- and a few days ago, my new shoes finally arrived in the mail. (By the way, what happened to free overnight shipping, Zappos?) I stuck an insert for arch support in each shoe, and today, I broke in the MX840s with a rigorous Plyo session.
The verdict? True to form, my cross trainers handled all the lateral movement with aplomb. I felt remarkably stable while cranking out Airborne Heismans, Monster Truck Tires, Football Heroes, and Lateral Leapfrogs. I was less tentative about my landings, and could plant my feet without worrying about rolling my ankles. But when performing moves with no lateral action required, I definitely missed the cushioning provided by my running shoes. During Squat Reach Jumps, Mary Katherines and Run Stance Squat Switch Pick Ups (or whatever the fuck they're called), I felt the impact of the landings in my knees. (It's possible, though, that I'm just a clod who hasn't yet learned to land softly per Tony's instructions.)
All in all, I give cross trainers a big thumbs up, as long as you have a thick mat or rug underfoot.
[UPDATED: I totally disavow and