Hello everyone. Good topic here, and I've got little else to do at the moment, so watch out!
This subject of boot flex/stiffness has come up often in the past here at EpicSki, and we've had some pretty good discussions. Do a search on "boot flex" in the Technique section, and you'll find several links.
I'll throw out a few points as food for thought anyway. I maintain that there is more myth, half-truth, and just plain
wrong "conventional wisdom" about this particular issue than perhaps anything else in skiing.I maintain that the need for "ankle flex" is largely a myth, and that, given sufficient skill, good technique, and consistency of balance, stiffer boots (fore and aft) are an advantage.
It is possible to go too stiff, though, and who among us has sufficient skill, perfect technique, or perfectly consistent balance? Before I go on, let's keep in mind the sometimes vast chasm that exists between describing theoretically ideal technique and real-world skiing. Theoretically, skiers rarely if ever need to flex their ankles. It is in the real world of imperfections, imbalances, and errors that the need for SOME amount of boot flex comes into play, sometimes.
First, it should be quite obvious that skis do not
respond to "boot flex" or "ankle flex." They do
respond to pressure fore and aft, which may or may not change when the ankle bends. As far as the skis are concerned, they couldn't care less whether your ankles are bent or not--they'll respond to the same input regardless of the degree of ankle flex.
Boots are very simply "handles" by which we hold and manipulate and communicate with our skis. They are the two-way connection, the sole interface (sorry!), between us and our equipment. Clearly, the less slop and play, and the more rigid the handle, the more direct and precise the connection. All else being equal, a completely rigid (i.e. concrete) boot would offer the most sensitive, direct, and advantageous linkage between us and our skis. Soft boots are to the ski what a soft rubber hinge between our ski poles and grips would be!
Of course, all else is rarely equal. The ankles do have important functions in human movement. Primarily, they are one link in the long chain of joints that affect fore-aft balance and allow us to flex and extend. Flexing and extending are
important movements in skiing, allowing us to regulate pressure, absorb shocks, and swallow moguls. I suspect that the biggest argument most "ankle flex/soft boot" proponents make is that the ankles need to bend as part of this chain when we flex and extend. They certainly do bend when we flex low without skis and boots on, so don't they need to do the same with
skis and boots?
In a word, NO!
Ankles, knees, hips, spine, neck, and arms work together to keep us balanced, harmonizing in ways we've practiced and perfected since the first time we stood upright. Any one of these joints, moving in isolation, would change fore-aft balance, but they rarely move in isolation. As you bend down to pick up an object on the ground, your knees bend, moving you back, and your ankles, hips, and spine flex forward to compensate. Hands and arms may reach forward somewhat as well. That's the "normal" motion when every joint functions. But lock up any one of those joints--with a splint, a fused spine, a knee brace, a cast--or a rigid ski boot--and the other joints can and will compensate. Yes, there's some learning involved. New movements, or at least different degrees of "proportional flexing," must occur within the chain of joints. It takes time and practice to develop skill at these new movements, but it is worth the effort!
Once a skier learns to flex and extend independently of the ankles, he/she can take advantage of the benefits of stiff boots described earlier. Stiff boots add some steepness to the learning curve for skiing, because they require that skiers learn new movement patterns. But whoever said skiing was easy? This is one of the most critical of all skiing skills, and perhaps one of the most overlooked.
Here's a graphic that illustrates these fore-aft issues. Note in particular Figures 7-10, which illustrate flexing and extending with and without stiff ski boots and ankle flex.
Once we learn to flex and extend independently of the ankle, then we can use that ankle actively to regulate fore-aft pressure. As the first (lowest) link in the chain, even a subtle movement of the ankle produces a large affect on fore-aft balance. While today's skis rarely require leverage (fore-aft pressure) to function at their best, whenever I do need a little extra tip or tail pressure, stiff boots transmit my subtle ankle movements directly, and completely, to the skis. Soft boots do not!
While I rarely pressure either the tongues or the cuffs of my boots, at least when I'm in balance, I like the cuffs snug and stiff. They give me constant feedback, a solid reference point for my balance. And they provide instant, firm support to help me quickly regain my balance when I lose it, too.
How stiff is too stiff, then? Part of the answer lies in your skill level--particularly, how skillful you've become at the ski-specific flexing-extending movements described above. Beginners will certainly find softer boots more forgiving of their lack of skill. On the other hand, if they provide an excuse for not learning these new skills, they may just contribute to bad habits. Those skills are important! Better, I say, to get "real" ski boots and learn to use them, right from the start.
Stiff boots transmit ALL your input more directly to your skis--good ones, and mistakes too. The more mistakes you make, the more it may make sense to soften your boots a bit. Softer boots are, once again, more forgiving of errors, and most skiers would find stiff World Cup race boots just way too demanding and unforgiving.
And even the best skiers and racers can go too stiff, not because they need to "flex" their boots as part of their technique--I've already addressed that myth. But because some amount of flex helps absorb the natural shocks and vibrations of skiing across ruts and bumps, smoothing out the quick fore-aft and vertical pressure jolts, and allowing the skis to glide faster and carve cleaner. For the jolts that occur more quickly than any skier could react, some boot flex helps, like the stiff but necessarily compliant shock absorbers of a race car.
What about mogul skiers? Many skiers believe that skiing moguls requires softer boots, to allow them to flex and extend deeply. But, while a mistake in moguls with stiff race boots will provide a painful reminder to your shins, soft boots are still not required for moguls. Personally, because being thrown out of balance, sometimes severely, is inevitable in moguls, I appreciate the ability to recover quickly that only stiffer boots can provide.
Here's an animation that I've posted here before, illustrating the "back-pedaling" motion required to absorb moguls while maintaining fore-aft balance. Note that the one angle that never changes is the angle of the skier's ankles. Ideally, this skier's shins will remain constantly "neutral" in the boot cuffs--in contact with, but not pressuring, the tongues or the backs:
As the knees bend, the skier flexes strongly forward at the hips and spine, and reaches forward with the arms, to compensate for the inability (and undesirability) of flexing the ankles, thereby maintaining fore-aft balance. Freed of their role in flexing and extending, the ankles are once again able to make important, constant, subtle adjustments in fore-aft balance.
Finally, what is far more critical than "boot flex," especially with boots that allow little, is boot setup. In particular, the degree of forward lean--the "neutral" angle at which the boots hold the shins when there is no fore-aft pressure on their cuffs, becomes critical. This angle is a function of both boot cuff angle and the binding ramp angle ("delta angle") that may tilt the entire boot. It's also a function of the skier's leg. Those like me with skinny calf muscles will find any boot more upright than someone with heavy, muscular, or low calves.
If a boot is too upright, bending the knees requires an exaggerated amount of compensation in the hips, waist, spine, and arms. Stiff boots that are too upright severely limit your range of flexion, preventing you from fully absorbing a mogul without being thrown backward. On the other hand, too much forward lean limits the amount of extension
available without over-pressuring the ski tips.
Removing the ankles from the flexion-extension chain does restrict the range of motion available somewhat. So it is essential to find a "neutral" ankle/shin angle that optimizes the range. Too upright limits the low (flexion) end. Too forward limits the high (extension) end. And both require an unnatural stance just to stand comfortably in balance (see Figures 3 and 4 in the first illustration, showing two skiers "in balance," one with boots too upright, the other too forward). "Just right" is just critical!
So there's a little to think about. Again, in the real world of real people skiing real mountains, some degree of boot flex is handy, if not essential. But not for the reasons so many people suggest! There is no inherent or universal need to "flex the boots" when turning, despite overwhelming "conventional wisdom" that says otherwise. Skis do not respond to boot flex!
I'll wrap this up with a list of statements, all of which are fairly common, but all of which are myths worth, at the very least, a closer look.Common Myths:
- Ankle flex is a fundamental necessity.</font>
- Skiers must always "flex" as they go through turns.</font>
- Forward pressure bias is important for initiating turns.</font>
- Softer skis need softer boots.</font>
- Shorter skis need softer boots.</font>
- Deeper sidecut skis need softer boots.</font>
- Moguls need softer boots.</font>
- Forward lean angle directly affects fore-aft balance point.</font>
- Position alone is indicative of fore-aft balance.</font>
- Lateral stiffness is more important than fore-aft stiffness.</font>
Don't believe a word of it!
Bob Barnes[ October 11, 2003, 01:48 PM: Message edited by: Bob Barnes/Colorado ]