A while ago, we mentioned stack and drop and how important they are to minimalist footwear and foot health in general. Today, we'll introduce another term that - depending on the foot wear - is just as important as stack and drop: Toe spring.
How does this even work?
Toe spring refers to the angle at which the toe of a shoe points upward. Generally speaking, most shoes when placed on a flat surface will have about a 15% angle (industry standard, for now). Some shoes have more, some have less. If you want to see some crazy looking shoes, just look to men's dress shoes and you'll see some wild things like the dress shoe above. (Apologies to any elves who may be offended).
But before we can really dig into toe spring, it's important to remember what it is our toes do for us. There job is more than just to get stubbed or decorated. They provide balance, and when they're healthy, they'll lay flat on the ground and stay in contact with the ground the majority of the time we walk - that is if we're barefoot. Put on a pair of shoes with a toe spring, and this is no longer the case. Also keep in mind that we have tendons connecting to both the bottom and tops of our toes. The diagram above shows the Extensor Tendons attaching to the top of the toes while the Plantar Fascia attaches to the bottom. Tendons act like rubber bands that are connected to bone on one end and muscle on the other (sometimes it's an organ, like your eye...). When the muscle contracts the tendons stretch. If you've ever used a hair tie or an old rubber band that's been stretched for an extended period of time, you know that eventually the elasticity is lost and the rubber band or hair tie gets looser and retains some of it's old shape. Your tendons can do the same thing, and an elevated Toe Spring can help stretch your tendons in negative ways.
Better than the first, but not great, especially with that rigid sole
Proponents of toe spring will give you a few reasons why toe spring is a good thing. They'll tell you it helps to decrease forces at the ball of your foot incurred during unruly pronation. Believe it or not, everyone pronates. Everyone rolls to some degree across the ball of the foot and off the toes - think toe-off. If you didn't have your toes, to toe-off with, you'd be toeing-off with the ball of your foot, and that hurts. Try it, get up lift your toes up and try to walk around. It hurts. They'll also tell you that toe spring helps to mitigate mechanical forces generated in the calf and Achilles Tendon. If you know anything about running, you know that a healthy arch and Achilles Tendon act as giant springs to help absorb forces and propel you forward, why then would you want to lessen the forces generated within them? Remember Newton and his Laws of Motion? Those forces your body is generating are going somewhere, While toe spring may mitigate forces in the Achilles Tendon, it's putting it onto something else that wasn't designed to take the force of landing and toe-off. But then, proponents of toe spring are probably trying to sell you a $300 orthotic as well...
The flexible sole negates some of the effect of the toe spring
Now if you look at most athletic shoes, they don't have an unruly toe spring like some dress shoes, none-the-less, they do have some toe spring and this is when we really must be careful. One of the big differences between dress shoes and athletic shoes is the hardness of the sole. A thick, hard sole on a fancy dress shoe is pretty darn rigid and won't change much through a stride. Athletic shoes on the other hand usually have a flexible sole so even if there is some toe spring, as you walk or run through a full phase, your toes should be strong enough to overcompensate for the spring and essentially nullify it. However, this isn't always the case especially in shoes with a firmer and/or overly cushioned sole.
Perfection! Zero toe spring!
So what do you do? Buy footwear without a toe spring! And of course, if you can't you can always find something with a flexible sole that allows your toes to act naturally despite an unnatural shape. And if you're still stuck, bend your shoes backwards on themselves or press them under some heavy object for a day or so. It may not be the most important feature of minimalist footwear, but toe spring certainly is important.