You've mentioned to me in the past the issues with the ever popular Nike Shox training shoe as well as high heels in women. What's are the potential problems?
When you elevate the heels chronically - via certain sneakers, high-heels, or any other footwear - you lose range of motion in dorsiflexion (think toe-to-shin range of motion). When you lack mobility at a joint, your body tries to compensate by looking anywhere it can to find range of motion. In the case of restricted ankle mobility, you turn the foot outward and internally rotate your lower and upper legs to make up for the deficit. This occurs as torque is "converted" through subtalar joint pronation.
As the leg rotates inward (think of the upper leg swiveling in your hip joint socket), you lose range of motion in external rotation at your hip. This is one of several reasons why females have a tendency to let their knees fall inward when they squat, lunge, deadlift, etc. And, it can relate to anterior/lateral knee pain (think of the term patellofemoral pain ... you've got restriction on things pulling on the patella, and on the things controlling the femur ... it's no wonder that they're out of whack relative to one another). And, by tightening up at the ankle and the hip, you've taken a joint (knee) that should be stable (it's just a hinge) and made it mobile/unstable. You can also get problems at the hip and lower back because ...
Just as losing range of motion at the ankle messes with how your leg is aligned, losing range of motion at your hip - both in external rotation and hip extension - leads to extra range of motion at your lumbar spine (lower back). We want our lower back to be completely stable so that it can transfer force from our lower body to our upper body and vice versa; if you have a lot of range of motion at your lower back, you don't transfer force effectively, and the vertebrae themselves can get irritated. This can lead to bone problems (think stress fractures in gymnasts), nerve issues (vertebrae impinge on discs/nerve roots), or muscular troubles (basic strains).
So, the take-home message is that crappy ankle mobility - as caused by high-top shoes, excessive ankle taping, poor footwear (heel lifts) - can cause any of a number of problems further up the kinetic chain. Sure, we see plantar fasciitis, Achilles tendinosis, and shin splints, but that's just the tip of the iceberg in terms of what can happen.
How do we fix the problems? First, get out of the bad footwear and pick up a shoe that puts you closer in contact with the ground. Second, go barefoot more often (we do it for all our dynamic flexibility warm-ups and about 50% of the volume of our lifting sessions). Third, incorporate specific ankle (and hip) mobility drills - as featured in our Magnificent Mobility DVD .
Oh, I should mention that elevating the heels in women is also problematic simply because it shifts the weight so far forward. If we're dealing with a population that needs to increase recruitment of the glutes and hamstrings, why are we throwing more stress on the quads?