In a healthy subject, toes go numb due to lack of circulation. Lack of circulation comes from two primary sources: Either there is localized pressure on the skin preventing capillary refill, or the flow to the toes has been affected by a contour mismatch over the instep. Truly excessive ramp can flush the blood out of the forefoot as well. Various medical conditions, such as diabetes and Reynaud’s Syndrome, will affect circulation and thus warmth. Vasoconstrictors such as caffeine and common antihistimines may also play a part.
Cramping can be a byproduct of constant muscle tension, or unrelenting pressure.
Pressure can be derived from an improperly tuned footbed, providing pressure from below, combined with downward pressure from the padding of the boot tongue. Hot spots under the heel and forefoot may be a byproduct of no foot support and lack of instep clearance.
In the event of grabbing toes, the boot is too large/loose, and the toes scrabble around looking for security. Grabbing toes in the presence of arch support can also lead to foot cramps.
Telemark skiing has one specific challenge of its own, which can lead to rather exquisite pain in the arch.
Leg fatigue and the myth of fitness
If you cannot rest on a ‘quiet’ bone stack, your legs will tire prematurely.
Too many skiers are under the impression that their fatigue has something to do with a lack of conditioning. In fact, quadriceps fatigue has almost everything to do with boot geometry. You, and your skis, should be ‘at rest’ simultaneously. If you cannot make a turn without winding up most of the large muscles in your legs, you have an equipment problem. Quite often, the forward lean and ramp of the average boot directs too much pressure to the shovel of the ski. Statically, this is not a problem, but once glide begins, the system becomes dynamic, and too much pressure to the shovel is not a good thing. A lack of stability generally leads to muscle tension, as in walking across a slippery surface. Under load, this tension increases dramatically.
Leaning on your boots for relief is best confined to the lift line, as doing so otherwise will make your skis behave poorly, and probably damage your shins.
Many years ago, (meaning 19), I hypothesized that if I had not been physically robust, I would have learned to ski more effectively….
Over the course of the last several years, I have undertaken an informal research project to determine just how much fitness one needs in order to ski effectively. To that end, I have done absolutely no extracurricular conditioning whatsoever. And I find that it really doesn’t affect my skiing performance. It does affect my stamina, which is to say that I don’t want to ski all day, but the quality of the skiing itself has hardly suffered.
While it does take some fitness to learn to ski, it may not take as much as you think.
And this is not to diminish the need for fitness for an athletic endeavor, but rather to understand that fitness itself is no substitute for finesse.
Forward lean, angles of incidence, fore and aft.
How much forward lean do you need? Well, how much pizza in a large pie?
More often than not, the angle of incidence between the front of the boot cuff and a skier’s shin is appropriate when the skier is resting comfortably on ‘faceted’ knee joints. Ideally, the forward lean of the cuff will support this relationship of the femur to tibia. Unfortunately, the back of the cuff seldom matches the bulk (or lack thereof) of the back of the leg, which forces the knee joint either forward or backward of ideal flexion.
If you find yourself ‘hanging’ on the front of your boots in the lift line, or while standing around indoors; you have too much forward lean in your boots. Conversely, if you find it difficult to flex your knees, skiing with straight legs and shoulders pitched forward, you have insufficient aft support. Too much or not enough, both will have a negative impact on your skiing.
I have built several ‘backward lean’ boots. They looked really funny, but worked.
One of my co-workers has the equivalent of a sofa cushion, a pop tart, and a child’s skateboard behind each liner…
Pain in the forefoot can be caused by too much tilt to the boot board, and/or too much forward lean in the boot, both of which direct the majority of turn induced stresses to the front of the foot. Ideally, weight should default to the entire foot structure, with easy options fore and aft.
Lack of support under a mobile foot can put too much pressure on too few bones. There is a small bone (sometimes two), like a kneecap, under the first metatarsal head. A painful hot spot can develop here if the fat pad normally covering this bone is displaced; a condition aggravated by disproportional forefoot weighting.
Too much forward lean/ramp becomes apparent, by way of burning quads, when the snow gets deeper or stickier.
Bunions: generally hereditary. Exacerbated by lack of foot support, excessive ramp/forward lean, narrow toe box ‘folding’ toes. Can often be mitigated without surgery.
Inflammation of the nerve conduits between the metatarsals. Usually caused by those bones being squeezed for extended periods. Can be relieved by widening the boot, and using a neuroma pad and/or transverse arch in the footbed.
Heel lift during flex, range of motion
If a skier has insufficient dorsiflexion, their heels will lift with only slight forward flexion at the knee. If this skier tries to nail their heels down with more padding in the ankle pocket, they run the risk of damage to the Achilles tendon, or development of bone spurs between the tibia distal and the talus. Lack of dorsiflexion is one of the few cases where use of additional heel lift is justified. Another case is general atrophy of the Achilles and the attached muscles, as in the long-term use of high-heeled footwear. The obvious drawback is that a performance affecting parameter is employed to resolve what amounts to a ‘fit/comfort’ issue.
When the combined ramp of the boot and binding is excessive, the skier will need more forward flex to compensate for ‘dislocation’ in the fore/aft plane. Quite often the boot runs out of flex, making a fulcrum of the shin, such that the heel lifts.
Fused ankles, clubfoot, minor hind-foot deformities (sore Achilles) will require some sort of extracurricular support modifications.
Constant pressure + time will begin the process of calcification, as the body seeks to protect itself, in much the same way that an oyster creates a pearl. Common locations are the fifth metatarsal proximal, 5th phalange proximal, 1st metatarsal distal, Navicular, medial and lateral Malleoli, and the Calcaneous. Generally, these are all derived from shell contour mismatches.
If the heel lifts during forward flex, it will often run into the upper contour of the heel pocket of the shell, the usual precursor to a heel spur.
Lateral calcaneal heel spur development is common to misaligned skiers seeking edge contact through knee flexion and inward roll at the hip socket. As well as to those favoring knee angulation as a typical means of edging.
Shin bang/ abrasion
The face of the shin is not a load-bearing surface. If you constantly lean on the tongue of the boot, or aim to flex excessively, your shins will be affected.
So, knock it off already. ‘Driving’ your skis is a fools errand.
Foot health, tissue damage, etc
Wash your socks. Keep your feet clean. Trim your nails. Tend to cuts, abrasions, hot spots, etc. Do not walk around the locker room in your bare feet. The latter is one of the primary means of acquiring/sharing Plantar warts.