Windlass action is a test for flexibility in the mid-tarsal joint. This is the series of joints that create the arch in your foot. The more flexible your arch, the more supportive (or rigid) the foot bed will need to be. Conversely, the more rigid your arch, the more flexible (or shock absorbing) the foot bed should be. Below is an example of the windlass test. Notice the amount of change in the arch height when the toes are lifted. This is a good example of a flexible arch.
Forefoot Mobility, or what looks like forefoot pronation, may indicate a very flexible foot. I am not going to go into the finer points of forefoot flexibilites and mis-alignments (that is a whole can of worms), but suffice it to say that the more flexible the forefoot, the more supportive / rigid the footbed ought to be. The failure to distinguish the difference between a flexible forefoot and a rigid forefoot can be disastrous. The failure to recognize the difference between flexible and rigid in any of these aspects can lead to discomfort, or even injury! This is why you might want to go to a respected shop that deals with boot fitting issues day in and day out.
A foot bed system is best when it allows the boot fitter to make changes to the foot bed specific to a given person’s particular needs. Some foot beds can’t be changed once the product has been made; others can’t be changed because of the materials.
This brings up a question that I get asked often by customers. “I have an orthotic that my podiatrist made for me. Can I use that in my ski boot?” Typically, the answer is No. The orthotic was probably made for a very specific issue. It will probably be too large and thick for the boot. Even if it is 3/4 length, the heel cup probably will not seat into the heel pocket of the boot, and a knowledgeable boot fitter will not alter a prescription orthotic.
OK, so why is the foot bed so important? If you haven’t guessed by now, it is to control the flexibilities of the foot. A highly mobile foot will not transfer energy to the ski efficiently. There will be a lag between what the skier wants to do and what the ski actually does.
Second, a custom foot bed creates a platform to evenly distribute the skier’s weight across the whole of the foot, thereby making the boot that much more comfortable. When both of these goals are achieved, the whole skeleton moves more effectively through the fore & aft and medial & lateral movements of skiing.
Canting / Stance Balancing
The next piece of the puzzle (and probably the most important) is Stance Balancing, or what is more commonly known as “canting.”
This is the process where the boot fitter measures the relationship between the center of knee mass and the center of the foot in the frontal plane. In other words, how far inward (medial) or outward (lateral) the knee is relative to the 2nd and 3rd toe.
The knee is considered to be in a neutral position when it is approximately one degree inside the center of the foot. From a “neutral” stance, the ski will be flat under foot rather than overly pressuring either the inside or outside edge of the ski.
If the knee is too far outside of the center of the foot (lateral), then the ski will be over-edged, and the downhill or outside ski will initiate a turn more quickly than the inside / uphill ski. At the end of the turn, the skier usually has to lift the outside (downhill) ski to release the edge in order to initiate the new turn and avoid crossing skis. If the knee is too far to the inside of the center of the foot (medial), then the ski is considered to be under edged. The skier has to tip the knee even further in to engage the edge, resulting in a knee-chasing stance (one knee tucked behind the other).
Many bad ski habits derive from both of these scenarios, eventually turning these skiers into terminal intermediates at best.
To correct the problem, the boot fitter finds the difference between the skier’s natural stance and the optimal neutral position, then modifies the boot sole in such a way as to change and adjust the stance of the boot to accommodate the skier’s natural stance. (In other words, we want to allow the skier to stand naturally, but in a neutral position on the ski. That is achieved by altering the boot, not the skier’s stance.) This can relieve the skier of constant muscular holding patterns created by the non-neutral stance.
A neutral stance is more relaxed and natural, and your muscles are now free to make the movements required to ski. You’ll be less fatigued, and you’ll probably be able to ski many more hours and have fewer aches and pains from the day.
Sounds pretty good, no?