Question: What percentage of the entire ski length must be used as the front part?
About the article "Nordic combined", section "Ski jumping equipment".

Candidate passages:
 Bindings
 The binding must be mounted parallel to the run-direction.
The binding must be placed in such a way that a maximum 57% of the entire ski length is used as the front part.
 Boots
 High-backed, flexible yet firm boots with a low cut at the front.
They are designed to allow the skier to lean forward during flight.
 Connection cord
 Part of the binding; a cord that attaches the ski to the boot and prevents the wobbling of skis during flight.
 Ski jumping suit
 All portions of the ski jumping suit must be made of the same material and must show a certain air permeability.
The size of the suit must conform to the body shape in an upright position with certain tolerances.
 Jumping skis
 Jumping skis are manufactured especially for use on ski jumping hills.
Skis with a length of a maximum 146% of the total body height of the competitor may be used.
The curvature and shape of the skis is restricted by certain geometric features.
Competition skiing uses specifically designed towboats.
Most towboats have a very small hull and a flat bottom to minimize wake.
A true tournament ski boat will have a direct drive motor shaft that centers the weight in the boat for an optimal wake shape.
However, some recreational ski boats will have the motor placed in the back of the boat (v-drive), which creates a bigger wake.
Permitted towboats used for tournament water skiing are the Mastercraft ProStar 197, Mastercraft ProStar 190, Nautique 200, Malibu Response TXi, and Centurion Carbon Pro.
These boats have ability to pull skiers for trick skiing, jumping, and slalom.
Recreational boats can serve as water skiing platforms as well as other purposes such as cruising and fishing.
Popular boat types include bowriders, deckboats, cuddy cabins, and jetboats.
The towboat must be capable of maintaining the proper speed.
Speeds vary with the skier's weight, experience level, comfort level, and type of skiing.
For example, a child on two skis would require speeds of , whereas an adult on one ski might require as high as .
Barefoot skiing requires speeds of approximately .
Competition speeds have a wide range: as slow as up to for slalom water skiing, and approaching in water ski racing.
The boat must be equipped with a ski rope and handle.
The tow rope must be sufficiently long for maneuvering, with a recommended length of (within tolerance) although length varies widely depending on the type of water skiing and the skier's skill level.
Competition requirements on rope construction have changed over the years, from "quarter-inch polypropylene rope" in 1992 to the 2003 flexibility as long as the same specification is used "for the entire event."
The rope and handle are anchored to the boat and played out at the stern.
This anchor point on a recreation boat is commonly a tow ring or cleat, mounted on the boat's stern.
For more dedicated skiers, a metal ski pylon is placed in the center of the boat in front of the engine to connect the skier.
This pylon is mounted securely, since a skilled slalom skier can put a considerable amount of tension in the ski rope and the pylon. 
Three classifications exist for skiers with visual disabilities.
Vision impaired skiers generally follow the same rules as sighted skiers laid out by the International Ski Federation.
The major difference is skiers in this group follow sighted guides who give the skiers vocal directions on where to ski.
The guide for B1 skiers generally skis behind the skier in order to maximize the ability of the skier to hear the guide.
The guide tells the skier things like when weight should be shifted, elements coming up on the course, and how to position themselves to maximize the diagonal run of the course.
Guides for B2 and B3 skiers often position themselves differently as the skiers have some vision, which means the things a guide assists with will be different from what is required of a skier who has almost no sight.
Standing skiers generally follow the same rules as sighted skiers laid out by the International Ski Federation.
They may wear a prosthesis, use modified length ski poles, and/or use a ski pole called an outrigger that had a small ski on the end.
LW1 skiers use two poles but may ski on one or two skis.
LW2 skiers use one ski and two poles.
LW3, LW4 skiers use two skis and two poles.
LW5 and LW7 skiers do not use poles.
LW6 and LW8 skiers use two ski and one pole.
Sit skiers generally follow the same rules as sighted skiers laid out by the International Ski Federation.
They use a mono-ski, which has a specially fitted chair attached to the single ski.
The skiers also use outrigrer poles to aid in balance.
The monoskis are sometimes called tubs or buckets.
Wheelchair users are classified as sit-skiers.
Classifications were combined for one event in 2002 when there were fewer than six competitors in a single class.
When classes are combined, a percentage system is used to determine the winner of a race.
The Canadian Paralympic Committee explains how this works with the following example: "Athlete A is classified as LW6 with a factor of 91% finishes the race in 1 minute, their final race time is 54.6 seconds.
Athlete B is classified as LW5 with a factor of 79% finishes the race in 1 minute and 2 seconds, their final race time is 48.98 seconds.
Athlete B wins.
Therefore, the athlete who completed the race fastest may not be the winner and gold medalist.
"In the United States for competitors with intellectual disabilities in events governed by the Special Olympics, para-Alpine skiing events include slalom, giant slalom and downhill. 
Skis design is based on complex scientific principles.
Ski construction must address a variety of factors.
A ski must be light enough to glide on top of the snow, but must also be strong enough to withstand the weight of the skier.
Skis are built with a curvature in the length of the ski known as camber, which provides stability in uneven terrain and varying snow consistency.
The ski must also have the ability to bend to optimize maneuverability and accommodate weight shifts during turning.
All skis are designed with the same primary structure- a wood, steel, or foam core which is then surrounded by more durable water-resistant materials.
Combinations of varying ski shapes, weights, lengths and widths are designed for different types of skiing, such as downhill or slalom skiing. 
Beyl was a perfectionist and was unhappy with his plate design.
What he wanted was a lightweight solution that was easier to mount, yet retained the ability to absorb lateral forces.
His next design used a C-shaped piece that fit over the toe of the boot, eliminating the plate.
The toe of a contemporary ski boot is essentially hemispherical, so the single clip kept the boot centred and, by riding over the top of it, pressed down onto the ski.
Under a pure sideways release scenario, the clip would rotate to allow the boot to exit.
However, if the force was also to the front, as in the case of the ski tip catching a tree root or front of a mogul, the pivot would be too close to the line of motion to allow easy rotation.
To address this, the entire body of the binding was also pivoted.
In this sort of release scenario, the binding as a whole would rotate, and eventually the force would be far enough to the side that the clip would be forced sideways.
As before, Beyl wanted a US-sounding name for his new binding, and selected "Nevada".
The binding was released in 1950, along with a Nevada-branded cable binding of conventional design.
The Nevada toe was the first modern ski binding that worked safely with any unmodified boot, eschewing attempts to attach to the sole or use add-on plates or clips.
The basic two-pivot design has become universal, and used with only minor modifications to this day.