To clarify this term, zero-drop means that there is no height difference between the heel and toe of the shoe. This does not necessarily mean that there is no cushioning (if there's an inch of cushioning at both the heel and the toe, it's still zero-drop). Zero-drop shoes mimic barefoot conditions because, when you walk without shoes, your heel and toe are at the same level.
So, obviously, we've been hearing about more "minimal" shoes for a while now... that 12mm (running shoes traditionally have a 12mm difference in height from the heel to the toe) are simply awful and cause all of these injuries blah blah blah. So, naturally, one would expect that everyone should be working to transition from 12mm down to 0mm and then no one would ever be injured again... right?
Nope.
Zero-drop shoes are not for everyone, just like neutral shoes aren't for everyone, or stability shoes, or super-cushioned shoes, or... you get the point. If you're prone to calf-complex and achilles issues, plantar fasciitis... heck, any problem from your knee down, you might want to proceed transitioning with caution. While lower-drop shoes most definitely reduce the impact/torque forces on your joints (by promoting a more mid-foot strike pattern), they initially put more stress on your calf and achilles. So, running a few shorter runs in lower-drop shoes is also a good idea... really, it's the same advice I'd give for breaking in any new pair of shoes. Additionally, strengthening and stretching the muscles/tendons in your lower leg before and during a gradual move to a lower-drop shoe is a must.
