question: how do skiers finish high jumps without breaking their legs?
comment: Breaking legs requires force, if I remember correctly it's about 400 foot pounds for a healthy person. This force has to be absorbed. Because the skier rarely just stops moving the force isn't absorbed completely most of it is carried through momentum.
passages: Timing is crucial and there is next to no margin for error at this phase: a jump that begins too early or late off the table can mean the difference between an excellent, average or poor effort. Each athlete has their own method of generating as much inrun speed as possible, depending on such intricacies as crouch depth, hip and knee angle, arm placement, or how far the torso is positioned over the knees. Body weight is also a significant factor (see power-to-weight ratio), which has led to some athletes' health becoming a concern over the past two decades.
   Moments before being launched off the table, the athlete undergoes a sudden increase in g-force due to the curvature – or 'compression' – of the bottom of the inrun. They then initiate a very powerful, explosive jump that requires great leg strength. At this instant the skis are opened up into a horizontal "V" shape, legs straightened and spread apart, and arms held backwards as the athlete adopts their own unique flying position and enters the "transition". This highly aerodynamic "V" essentially turns the athlete into a 'flying wing', and all of this takes place in only a tenth of a second before the transition is then "closed" and the flying position maintained until the end of the jump.
   A number of athletes have been regarded as ski flying specialists for their ability to consistently produce very long jumps and often world records. Those who are currently active with notable ski flying achievements include (as of 3 February 2018):
  
  BULLET::::- Stefan Kraft – current world record holder with 253.5 m; nicknamed "Air Kraft" by Eurosport.
  
  BULLET::::- Peter Prevc – 2016 World Champion; former world record holder; first to land a jump of 250 m.
  
  BULLET::::- Robert Kranjec – 2012 World Champion; widely acknowledged as a ski flying expert.
  
  BULLET::::- Robert Johansson – former world record holder.
   A ski jumping hill is located on a steep slope, and it consists of the jumping ramp ("in-run"), take-off table, and a landing hill. Competitors glide down from a common point at the top of the in-run, achieving considerable speeds at the take-off table, where they take off with help of speed and their own leap. While airborne, they maintain an aerodynamic position with their bodies and skis, that would allow them to maximize the length of the jump. The landing slope is constructed so that the jumper's trajectory is near-parallel with it, and the athlete's relative height to the ground is gradually lost, allowing for a gentle and safe landing. The landing space is followed by an "out-run", a substantial flat or counter-inclined area that permits the skier to safely slow down. The out-run area is fenced and surrounded by a public auditorium.
   Section::::Alpine skiing career.:2009 season.
  
  On 16 July 2008, during the last training run in Mölltaler Gletscher, Austria, Zvejnieks crashed badly and broke his leg (fibula and tibia). He was determined to get back to skis as soon as possible, but it was too early. On 3 February 2009, he broke the same leg again. After several operations and a long time recovering, he began skiing again back in Mölltaler Gletcher on 14 October 2009.
  
  Section::::Alpine skiing career.:2010 season.
   In 2013, Ahonen revealed that the consequences of not reining in the jump prematurely in the way he did would have likely resulted in broken legs, or worse:
   If the competitor skis off the course during a para-Nordic race, they may be assisted back onto the course where they left it by a race official. Skiers cannot use their legs to break or steer during the race.
   The distance of a ski jump is measured from the end of the 'table' (the very tip of the 'inrun' ramp) to halfway between the athletes' feet when they touch ground. To qualify, the jump must be made in a sanctioned competition, or official trial or qualification runs for these, with a system to control the actual length. To win a competition, an athlete needs both distance and style, the latter of which is achieved by attaining a proper Telemark landing; therefore jumpers are not motivated to jump as far as possible, only as far necessary to attain a good landing. Jumps are invalid if the jumper falls, defined as touching the ground with his hands or body before reaching the fall line. However, if an athlete touches the snow with any part of their body after landing, and receives style points greater than 14 from at least three judges, the jump is valid and counts as an official world record.
   Much like aircraft wings, the skis are flexible to an extent, resulting in them bending and vibrating significantly upon takeoff. Maintaining stability in the air is paramount: a loss of balance, or a differential pressure under the skis, can lead to disaster (see list of ski flying accidents). A few athletes have a natural tendency to drift over to one side of the hill, invariably shortening their jump distance.
   There were two accidents during the individual women competition at normal hill.Line Jahr fell after her 90-meter jump and Léa Lemare fell after she jumped 84 meters.
  
  During the individual men competition at large hill, Thomas Morgenstern fell after his first jump. It happen just after he crossed the fall line and his notes were normal. Because of the fall, Morgenstern's knee was injured and he couldn't jump in some competitions after the Championships.
   The top of the hill is the start. This allows the jury to regulate the speed of the jumpers in varying wind conditions, by shortening or lengthening the distance along the in-run. The platform has a bar across it, which the jumper sits on. By leaning forward, the jumper will naturally start to glide down the prepared tracks along the in-run. The in-run normally has an angle of 38 to 36 degrees, which then curves into a transition; the last part of the in-run, the take-off, typically has an angle between 7 and 12 degrees downhill. The landing slope has a smooth curve which closely follows the profile of the ski jump; this means that the skier is never more than about above the ground. The skier will land on the landing slope, and the rules allow jumpers to land up to ten percent past the construction point. Past the landing slope is the outrun, which is either flat or even uphill, where the skier can slow down. The speed of the skier is normally measured about before the end of the takeoff; jumpers can reach speeds of on large hills and on ski flying hills.
   At the 2014 IFDS World Championships in Halifax, Canada, Tesch teamed with Fitzgibbon to win the two-person SKUD 18 class. Tesch and Fitzgibbon won the 2015 IFDS World Championships in Melbourne. Tesch and Fitzgibbon won the bronze medal in the SKUD 18 class at the 2016 World Championships held in Medemblik, Netherlands.
   BULLET::::- Jump – The skier travels over a small, fiberglass jump ramp. They have three jumps and the longest one successfully landed counts. Professionals can jump as far as 90 feet (27.4 meters).
  
  The current world record for Men's Open division of 29.9 meters (98.1 feet) was set by David Small on August 11, 2010.
  
  With a jump of 23.4 meters (76.8 feet) Ashleigh Stebbeings set the Women's Open world record on February 19, 2017.
  
  Tee-Jay Russo jumped 26.7 meters (87.6 feet) to set the Boy's division world record on December 29, 2018
   To have a chance of winning a competition, two consistently good jumps must be made. If an athlete finds themselves in an uncompetitive position after the first round, their challenge in the second is to make up ground via the attrition of other athletes, their own distance and style points, and wind/gate compensation. For an athlete who had a poor jump in round one, it is possible for them to climb up the order in round two with an exceptional jump, and if other competitors fall by the wayside. Conversely, a high-scoring athlete may lose their advantage from round one if their second jump is not up to par.
   BULLET::::- Roar Ljøkelsøy – 2004 and 2006 World Champion; described by David Goldstrom as "one of the top ski flyers of his time."
  
  BULLET::::- Mike Holland – last American ski jumper to hold a world record; quoted as saying "Ski flying was my speciality."
  
  Section::::Women in ski flying.
   BULLET::::- Ski Movie Segment: "Turbulent Flow" by Chaoz Productions
  
  BULLET::::- University of Utah PAC 12 Commercial Spot
  
  BULLET::::- Cellucor "Rise & Grind" Commercial Spot
  
  BULLET::::- Utah Olympic Oval Commercial Spot
  
  Section::::Results.
  
  BULLET::::- 2015 5th FIS World Championships halfpipe, Kreischberg Austria
  
  BULLET::::- 2014 6th SFR Tour, Tignes France
  
  BULLET::::- 2014 4th Aspen Open, Aspen CO
  
  BULLET::::- 2014 7th US Grand Prix, Park City UT
  
  BULLET::::- 2013 15th X Games, Tignes France
  
  BULLET::::- 2013 3rd SFR Tour, Tignes France
  
  BULLET::::- 2013 3rd Aspen Open, Aspen CO
  
  BULLET::::- 2013 4th North Face Open, Whistler BC
  
  BULLET::::- 2013 2nd Junior World Championships, Cadrona NZ
   For alpine events, a skier is allowed one push, without running, from the starting position at the start of the race. If the competitor skis off the course during a para-Nordic race, a race official may assist him or her back onto the course. Skiers cannot use their legs to break or steer during the race.
   Skiers are required to touch the ground in the Telemark landing style (), named after the Norwegian county of Telemark. This involves the landing with one foot in front of the other with knees slightly bent, mimicking the style of Telemark skiing. Failure to execute a Telemark landing leads to the deduction of style points, issued by the judges.
  
  Section::::Major competitions.
  
  All major ski jumping competitions are organized by the International Ski Federation.
   Lateral balance is an issue for LW6/8 skiers resulting from the missing arm, so skiing techniques are worked on by the skier to correct this. One technique used compensates for balance issues by using knee drives or hip motions. Unlike other para-Alpine disciplines, in slalom skiers are more likely to use a partial ski pole or a prosthetic to hold a ski pole.
  
  In the Biathlon, all Paralympic athletes shoot from a prone position. Athletes with amputations can use a rifle support while shooting.
  
  Section::::Sport.
   Once the athlete has taken flight, characteristics similar to that of a glider come into force. Ski flyers are able to cover such tremendous distances and land safely primarily due to the skis they use, which are substantially wider and longer than their cross-country or Alpine skiing counterparts. Each ski is first clipped in securely at the front of the boot, which is placed nearer the tail end of the ski and has an exaggerated forward slant. The heel of the boot is then attached to a wedge on the ski using a hinged binding peg and backup strap, allowing the athlete to lean forward into their preferred aerodynamic position and spread the skis wide apart.
   BULLET::::- Salt Lake City (1935) – Alf Engen landed a world record jump of 94.8 m (311 ft) during training; the latter is why it is officially not recognized as a world record.
  
  Section::::All jumps over 250 metres.
  
  As of 24 March 2019
  
  Section::::All jumps over 250 metres.:Most number of jumps over 250 metres.
  
  As of 24 March 2019, including invalid jumps:
  
  Section::::Summer world records.
   When distances beyond 200 m were first reached in 1994, Norwegian athletes have been the most prominent world record setters, with eleven records set by seven athletes as of March 2017. Norwegian and Slovenian athletes in particular have gained a reputation for being experts at ski flying.
  
  Section::::Accidents.
   By using the V-style, firstly pioneered by Swedish ski jumper Jan Boklöv in the mid-1980s, modern skiers are able to exceed the distance of the take-off hill by about 10% compared to the previous technique with parallel skis. Previous techniques included the Kongsberger technique, the Däescher technique and the Windisch technique. Until the mid-1960s, the ski jumper came down the in-run of the hill with both arms pointing forwards. This changed when the Däscher technique was pioneered by Andreas Däscher in the 1950s, as a modification of the Kongsberger and Windisch techniques. A lesser-used technique as of 2017 is the H-style which is essentially a combination of the parallel and V-styles, in which the skis are spread very wide apart and held parallel in an "H" shape. It is prominently used by Domen Prevc.
   Ski jumpers below the minimum safe body mass index are penalized with a shorter maximum ski length, reducing the aerodynamic lift they can achieve. These rules have been credited with stopping the most severe cases of underweight athletes, but some competitors still lose weight to maximize the distance they can achieve. In order to prevent an unfair advantage due to a "sailing" effect of the ski jumping suit, material, thickness and relative size of the suit are regulated.
  
  Section::::Techniques.
  
  Each jump is divided into four parts: in-run, take-off (jump), flight, and landing.
   BULLET::::- YouTube video - crash of Hans Grugger at "Mausefalle" - Thursday training run - 20-Jan-2011
  
  Section::::Various - Vertical Up.
  
  In the evening dawn of 25. February 2011 the first Streif VerticalUp race took place with a mass start. No rules, just up the route of the ski race, but in the "rucksack-class" up the less steep family ski piste. 79 in the speed class and 116 with rucksack reaches the goal: the start booth of the ski race. On shoes with spikes, with pickel or ski sticks, snow shoes, touring or cross-country skis, whatever.
  
presuppositions: Skiers legs should break due to the height of jumps.
corrections: Breaking a leg requires force which is carried through a skiers momentum.
raw_presuppositions: Skiers legs should break due to the height of jumps. Skiers should break their legs due to the height of their jumps.
raw_corrections: Breaking a leg requires force which is carried through a skiers momentum. Most of the force from landing is carried through momentum instead of absorbed by the skier.