Figure skating jumps are an element of three competitive

figure skating Figure skating is a sport in which individuals, pairs, or groups perform on figure skates on ice. It was the first winter sport to be included in the Olympic Games, when contested at the Figure skating at the 1908 Summer Olympics, 1908 Olympics ...

disciplines: men's singles, women's singles, and

pair skating Pair skating is a figure skating discipline defined by the International Skating Union (ISU) as "the skating of two persons in unison who perform their movements in such harmony with each other as to give the impression of genuine Pair Skating a ...

but not

ice dancing Ice dance (sometimes referred to as ice dancing) is a discipline of figure skating that historically draws from ballroom dancing. It joined the World Figure Skating Championships in 1952, and became a Winter Olympic Games medal sport in 1976 ...

. Jumping in figure skating is "relatively recent". They were originally individual

compulsory figures Compulsory figures or school figures were formerly a segment of figure skating, and gave the sport its name. They are the "circular patterns which skaters trace on the ice to demonstrate skill in placing clean turns evenly on round circles". For ...

, and sometimes special figures; many jumps were named after the skaters who invented them or from the figures from which they were developed. It was not until the early part of the 20th century, well after the establishment of organized skating competitions, when jumps with the potential of being completed with multiple revolutions were invented and when jumps were formally categorized. In the 1920s Austrian skaters began to perform the first double jumps in practice. Skaters experimented with jumps, and by the end of the period, the modern repertoire of jumps had been developed. Jumps did not have a major role in free skating programs during international competitions until the 1930s. During the post-war period and into the 1950s and early 1960s, triple jumps became more common for both male and female skaters, and a full repertoire of two-revolution jumps had been fully developed. In the 1980s men were expected to complete four or five difficult triple jumps, and women had to perform the easier triples. By the 1990s, after compulsory figures were removed from competitions, multi-revolution jumps became more important in figure skating. The six most common jumps can be divided into two groups: toe jumps (the toe loop, the

flip Flip, FLIP, or flips may refer to: People * Flip (nickname), a list of people * Lil' Flip (born 1981), American rapper * Flip Simmons, Australian actor and musician * Flip Wilson, American comedian Arts and entertainment Fictional characters * ...

, and the Lutz) and edge jumps (the Salchow, the

loop Loop or LOOP may refer to: Brands and enterprises * Loop (mobile), a Bulgarian virtual network operator and co-founder of Loop Live * Loop, clothing, a company founded by Carlos Vasquez in the 1990s and worn by Digable Planets * Loop Mobile, ...

, and the Axel). The Euler jump, which was known as a half-loop before 2018, is an edge jump. Jumps are also classified by the number of revolutions. Pair skaters perform two types of jumps: side-by-side jumps, in which jumps are accomplished side by side and in unison, and throw jumps, in which the woman performs the jump when assisted and propelled by her partner. According to the

International Skating Union The International Skating Union (ISU) is the international governing body for competitive ice skating disciplines, including figure skating, synchronized skating, speed skating, and short track speed skating. It was founded in Scheveningen ...

(ISU), jumps must have the following characteristics to earn the most points: they must have "very good height and very good length"; they must be executed effortlessly, including the rhythm demonstrated during jump combinations; and they must have good takeoffs and landings. The following are not required, but also taken into consideration: there must be steps executed before the beginning of the jump, or it must have either a creative or unexpected entry; the jump must match the music; and the skater must have, from the jump's takeoff to its landing, a "very good body position". A jump combination, defined as "two (or more) jumps performed in immediate succession", is executed when a skater's landing foot of the first jump is also the takeoff foot of the following jump. All jumps are considered in the order they are completed. Pair teams, both juniors and seniors, must perform one solo jump during their short programs. Jumps are divided into eight parts: the set-up, load, transition, pivot, takeoff, flight, landing, and exit. All jumps except the Axel and Waltz jumps are taken off while skating backward; Axels and Waltz jumps are entered into by skating forward. A skater's body absorbs up to 13–14 g-forces each time he or she lands from a jump, which may contribute to overuse injuries and stress fractures. Skaters add variations or unusual entries and exits to jumps to increase difficulty. Factors such as

angular momentum In physics, angular momentum (rarely, moment of momentum or rotational momentum) is the rotational analog of linear momentum. It is an important physical quantity because it is a conserved quantity—the total angular momentum of a closed sy ...

, the

moment of inertia The moment of inertia, otherwise known as the mass moment of inertia, angular mass, second moment of mass, or most accurately, rotational inertia, of a rigid body is a quantity that determines the torque needed for a desired angular accele ...

angular acceleration In physics, angular acceleration refers to the time rate of change of angular velocity. As there are two types of angular velocity, namely spin angular velocity and orbital angular velocity, there are naturally also two types of angular acceler ...

, and the skater's center of mass determines if a jump is successfully completed.

History

According to figure skating historian James R. Hines, jumping in figure skating is "relatively recent". Jumps were viewed as "acrobatic tricks, not as a part of a skater's art" and "had no place" in the skating practices in England during the 19th century, although skaters experimented with jumps from the ice during the last 25 years of the 1800s. Hops, or jumps without rotations, were done for safety reasons, to avoid obstacles, such as hats, barrels, and tree logs, on natural ice. In 1881 ''Spuren Auf Dem Eise'' ("Tracing on the Ice"), "a monumental publication describing the state of skating in Vienna", briefly mentioned jumps, describing three jumps in two pages. Jumping on skates was a part of the athletic side of free skating, and was considered inappropriate for female skaters. Hines says free skating movements such as

spirals In mathematics, a spiral is a curve which emanates from a point, moving farther away as it revolves around the point. Helices Two major definitions of "spiral" in the American Heritage Dictionary are:spread eagles,

spins The spins (as in having "the spins")Diane Marie Leiva. ''The Florida State University College of Education''Women's Voices on College Drinking: The First-Year College Experience"/ref> is an adverse reaction of intoxication that causes a state of ...

, and jumps were originally individual

, and sometimes special figures. For example, Norwegian skater Axel Paulsen, whom Hines calls "progressive", performed the first jump in competition, the Axel, which was named after him, at the first international competition in 1882, as a special figure. Jumps were also related to their corresponding figure; for example, the

loop jump The loop jump is an edge jump in the sport of figure skating. The skater executes it by taking off from the back outside edge of the skating foot, turning one rotation in the air, and landing on the back outside edge of the same foot. It is oft ...

. Other jumps, such as the Axel and the Salchow, were named after the skaters who invented them. It was not until the early part of the 20th century, well after the establishment of organized skating competitions, when jumps with the potential of being completed with multiple revolutions were invented and when jumps were formally categorized. These jumps became elements in athletic free skating programs, but they were not worth more points than no-revolution jumps and half-jumps. In the 1920s Austrian skaters began to perform the first double jumps in practice and refine rotations in the Axel. Skaters experimented with jumps, and by the end of the period, the modern repertoire of jumps had been developed. Jumps did not have a major role in free skating programs during international competitions until the 1930s. Athleticism in the sport increased between the world wars, especially by women like Norwegian world and Olympic champion Sonia Henie, who popularized short skirts which allowed female skaters to maneuver and perform jumps. When international competitions were interrupted by World WarII, double jumps by both men and women had become commonplace, and all jumps, except for the Axel, were being doubled. According to writer Ellyn Kestnbaum the development of rotational technique required for Axels and double jumps continued, especially in the United States and Czechoslovakia. Post-war skaters, according to Hines, "pushed the envelope of jumping to extremes that skaters of the 1930s would not have thought possible". For example, world champion Felix Kasper from Austria was well known for his athletic jumps, which were the longest and highest in the history of figure skating. Hines reported that his Axel measured four feet high and 25 feet from takeoff to landing. Both men and women, including women skaters from Great Britain, were doubling Salchows and loops in their competition programs. During the post-war period, American skater Dick Button, who "intentionally tried to bring a greater athleticism to men's skating", performed the first double Axel in competition in 1948 and the first triple jump, a triple loop, in 1952. Triple jumps, especially triple Salchows, became more common for male skaters during the 1950s and early 1960s, and female skaters, especially in North America, included a full repertoire of two-revolution jumps. By the late 1960s and early 1970s, men commonly performed triple Salchows and women regularly performed double Axels in competitions. Men would also include more difficult multi-revolution jumps like triple

flips Flip, FLIP, or flips may refer to: People * Flip (nickname), a list of people * Lil' Flip (born 1981), American rapper * Flip Simmons, Australian actor and musician * Flip Wilson, American comedian Arts and entertainment Fictional characters * ...

, Lutzes, and loops; women included triple Salchows and toe loops. In the 1980s men were expected to complete four or five difficult triple jumps, and women had to perform the easier triples such as the loop jump. By the 1990s, after compulsory figures were removed from competitions, multi-revolution jumps became more important in figure skating. According to Kestnbaum, jumps like the triple Lutz became more important during women's skating competitions. The last time a woman won a gold medal at the Olympics without a triple jump was

Dorothy Hamill Dorothy Stuart Hamill (born July 26, 1956) is a retired American figure skater. She is the 1976 Olympic champion and 1976 World champion in ladies' singles. Early life Hamill was born in Chicago, Illinois, to Chalmers and Carol Hamill. Her fa ...

at the 1976 Olympics. According to sports reporter Dvora Meyers, the "quad revolution in women's figure skating" of the early 21st century began in 2018, when Russian skater

Alexandra Trusova Alexandra "Sasha" Vyacheslavovna Trusova ( rus, Александра Вячеславовна Трусова, , ɐlʲɪˈksandrə ˈtrusəvə; born 23 June 2004) is a Russian figure skater. She is the 2022 Olympic silver medalist, the 2021 Wo ...

began performing a quadruple Salchow when she was still competing as a junior. Figure skating edges

Types of jumps

:Anomalies in the takeoff and landing are highlighted in ''bold and italic''. :All basic figure skating jumps are landed backwards. The six most common jumps can be divided into two groups: toe jumps (the toe loop, the flip, and the Lutz) and edge jumps (the Salchow, the loop, and the Axel). The Euler jump, which was known as a half-loop before 2018, is an edge jump. Toe jumps tend to be higher than edge jumps because skaters press the toe pick of their skate into the ice on takeoff. Both feet are on the ice at the time of takeoff, and the toe-pick in the ice at takeoff acts as a pole vault. It is impossible to add a half-revolution to toe jumps. Skaters accomplish edge jumps by leaving the ice from any of their skates' four possible edges; lift is "achieved from the spring gained by straightening of a bent knee in combination with a swing of the free leg". They require precise rotational control of the skater's upper body, arms, and free leg, and of how well he or she leans into the takeoff edge. The preparation going into the jump and its takeoff, as well as controlling the rotation of the preparation and takeoff, must be precisely timed. When a skater executes an edge jump, they must extend their leg and use their arms more than when they execute toe jumps. Jumps are also classified by the number of revolutions. For example, all single jumps, except for the Axel, include one revolution, double jumps include two revolution, and so on. More revolutions earn skaters earn more points. Double and triple versions have increased in importance "as a measure of technical and athletic ability, with attention paid to clean takeoffs and landings". Pair skaters perform two types of jumps: side-by-side jumps, in which jumps are accomplished side by side and in unison, and throw jumps, in which the woman performs the jump when assisted and propelled by her partner.

Euler

The Euler is an edge jump. It was known as the half-loop jump in

(ISU) regulations prior to the 2018–2019 season, when the name was changed. In Europe, the Euler is also called the Thorén jump, after its inventor, Swedish figure skater Per Thorén. The Euler is executed when a skater takes off from the back outside edge of one skate and lands on the opposite foot and edge. It is most commonly done prior to the third jump during a three-jump combination, and serves as a way to put a skater on the correct edge in order to attempt a

Salchow jump The Salchow jump is an edge jump in figure skating. It was named after its inventor, Ulrich Salchow, in 1909. The Salchow is accomplished with a takeoff from the back inside edge of one foot and a landing on the back outside edge of the opposite ...

or a

flip jump The flip jump (also called the flip) is a figure skating jump. The International Skating Union (ISU) defines a flip jump as "a toe jump that takes off from a back inside edge and lands on the back outside edge of the opposite foot".Media Guide ...

. It can be accomplished only as a single jump. The Euler has a base point value of 0.50 points, when used in combination between two listed jumps, and also becomes a listed jump.

Toe loop

The toe loop jump is the simplest jump in figure skating. It was invented in the 1920s by American professional figure skater Bruce Mapes. In competition the base value of a single toe loop is 0.40; the base value of a double toe loop is 1.30; the base value of a triple toe loop is 4.20; and the base value of a quadruple toe loop is 9.50.ISU No. 2168, p. 2 The toe loop is considered the simplest jump because not only do skaters use their toe-picks to execute it, their hips are already facing the direction in which they will rotate. The toe loop is the easier jump to add multiple rotations to because the toe-assisted takeoff adds power to the jump and because a skater can turn his or her body towards the assisting foot at takeoff, which slightly reduces the rotation needed in the air. It is often added to more difficult jumps during combinations, and is the most common second jump performed in combinations.USFS, p. 2 It is also the most commonly attempted jump, as well as "the most commonly cheated on take off jump", or a jump in which the first rotation starts on the ice rather than in the air. Adding a toe loop to combination jumps does not increase the difficulty of skaters' short or free skating programs.

Flip

The ISU defines a flip jump as "a toe jump that takes off from a back inside edge and lands on the back outside edge of the opposite foot". It is executed with assistance from the toe of the free foot. In competition the base value of a single flip is 0.50; the base value of a double flip is 1.80; the base value of a triple flip is 5.50; and the base value of a quadruple flip is 11.00.

Lutz

The ISU defines the Lutz jump as "a toe-pick assisted jump with an entrance from a back outside edge and landing on the back outside edge of the opposite foot". It is the second-most difficult jump in figure skating and "probably the second-most famous jump after the Axel". It is named after figure skater Alois Lutz from Vienna, Austria, who first performed it in 1913. In competition the base value of a single Lutz is 0.60; the base value of a double Lutz is 2.10; the base value of a triple Lutz is 5.90; and the base value of a quadruple Lutz is 11.50. A "cheated" Lutz jump without an outside edge is called a "flutz".

Salchow

The Salchow jump is an edge jump. It was named after its inventor, Ulrich Salchow, in 1909. The Salchow is accomplished with a takeoff from the back inside edge of one foot and a landing on the back outside edge of the opposite foot. It is "usually the first jump that skaters learn to double, and the first or second to triple". Timing is critical because both the takeoff and the landing must be on the backward edge. A Salchow is deemed cheated if the skate blade starts to turn forward before the takeoff, or if it has not turned completely backward when the skater lands back on the ice. In competition the base value of a single Salchow is 0.40; the base value of a double Salchow is 1.30; the base value of a triple Salchow is 4.30; and the base value of a quadruple Salchow is 9.70.

Loop

The loop jump is an edge jump. It was believed to be created by German figure skater Werner Rittberger, and is known as the Rittberger in Russian and German.U.S. Figure Skating, the loop jump is "the most fundamental of all the jumps". The skater executes it by taking off from the back outside edge of the skating foot, turning one rotation in the air, and landing on the back outside edge of the same foot. It is often performed as the second jump in a combination.Kestnbaum, p. 285 In competition the base value of the single loop jump is 0.50; the base value of a double loop is 1.70; the base value of a triple loop is 4.90; and the base value of a quadruple loop is 10.50. Bundesarchiv Bild 183-1989-0407-022, Midori Ito

Bundesarchiv Bild 183-1989-0407-022, Midori Ito

Axel

The Axel jump, also called the Axel Paulsen jump for its creator, Norwegian figure skater Axel Paulsen, is an edge jump.USFS, p. 1 It is figure skating's oldest and most difficult jump. The Axel jump is the most studied jump in figure skating. It is the only jump that begins with a forward takeoff, which makes it the easiest jump to identify. A double or triple Axel is required in both the short programs and free skating programs for junior and senior single skaters in all ISU competitions. The Axel has an extra half-rotation which, as figure skating expert Hannah Robbins says, makes a triple Axel "more a quadruple jump than a triple". Sports reporter Nora Princiotti says, about the triple Axel, "It takes incredible strength and body control for a skater to get enough height and to get into the jump fast enough to complete all the rotations before landing with a strong enough base to absorb the force generated." According to American skater Mirai Nagasu, "Falling on the triple Axel is really brutal." In competition the base value of a single Axel is 1.10; the base value of a double Axel is 3.30; the base value of a triple Axel is 8.00; and the base value of a quadruple Axel is 12.50. According to ''

The New York Times ''The New York Times'' (''the Times'', ''NYT'', or the Gray Lady) is a daily newspaper based in New York City with a worldwide readership reported in 2020 to comprise a declining 840,000 paid print subscribers, and a growing 6 million paid ...

'', the triple Axel has become more common for male skaters to perform; however, as of 2022, the quadruple Axel has been landed at two international competitions, by American skater Ilia Malinin.

Rules and regulations

Single skating

The

defines a jump element for both

single skating Single skating is a discipline of figure skating in which male and female skaters compete individually. Men's singles and women's singles are governed by the International Skating Union (ISU). Figure skating is the oldest winter sport contested ...

and

disciplines as "an individual jump, a jump combination or a jump sequence".S&P/ID 2018, p. 100 Jumps are not allowed in

ice dance Ice dance (sometimes referred to as ice dancing) is a discipline of figure skating that historically draws from ballroom dancing. It joined the World Figure Skating Championships in 1952, and became a Winter Olympic Games medal sport in 1976. Ac ...

. Also according to the ISU, jumps must have the following characteristics to earn the most points: they must have "very good height and very good length";ISU No. 2168, p. 13 they must be executed effortlessly, including the rhythm demonstrated during jump combinations; and they must have good takeoffs and landings. The following are not required, but also taken into consideration: there must be steps executed before the beginning of the jump, or it must have either a creative or unexpected entry; the jump must match the music; and the skater must have, from the jump's takeoff to its landing, a "very good body position". Somersault-type jumps, like the back flip, are not allowed. The back flip has been banned by the ISU since 1976 because it was deemed too dangerous and lacked "aesthetic value". A jump sequence consists of "two or three jumps of any number of revolutions" and is executed when a skater's landing foot of the first jump is also the takeoff foot of the following jump. The free foot can touch the ice, but there must be no weight transfer on it and if the skater makes one full revolution between the jumps, the element continues to be deemed a jump sequence and receives their full value. The second and/or third jump must be an Axel-type jump, "with a direct step from the landing curve of the first/second jump in to the takeoff curve of the Axel jump". The skater can also perform an Euler between jumps. Both a jump combination and jump sequence can "consist of the same or another single, double, triple or quadruple jump". In their free skating programs, skaters can include up to three jump combinations in their free skating programs; one jump combination or jump sequence can include up to three jumps, while the other two can include up to two jumps each. All jumps are considered in the order they are completed. If an extra jump or jumps are completed, only the first jump will be counted; jumps done later in the program will have no value.S&P/ID 2021, p. 105 The limitation on the number of jumps skaters can perform in their programs, called the "Zayak Rule" after American skater Elaine Zayak, has been in effect since 1983, after Zayak performed six triple jumps, four toe loop jumps, and two Salchows in her free skating program at the 1982 World Championships. Writer Ellyn Kestnbaum says the ISU established the rule "in order to encourage variety and balance rather than allowing a skater to rack up credit for demonstrating the same skill over and over". Kestnbaum also says that as rotations in jumps for both men and women have increased skaters have increased the difficulty of jumps by adding more difficult combinations and by adding difficult steps immediately before or after their jumps, resulting in "integrating the jumps more seamlessly into the flow of the program". In both the short program and free skating, any jump, jump combination, or jump sequence begun during the second half of the program earns extra points "in order to give credit for even distribution of difficulties in the program". As of the 2018–2019 season, however, only the last jump element performed during the short program and the final three jump elements performed during the free skate, counted in a skater's final score. ''International Figure Skating'' magazine called this regulation the "Zagitova Rule", named for

Alina Zagitova Alina Ilnazovna Zagitova ( rus, Алина Ильназовна Загитова, , ɐˈlʲinə zɐˈɡʲitəvə; born 18 May 2002) is a Russian figure skater of Volga- Tatar origin. She is the 2018 Olympic champion, the 2019 World champion, ...

from Russia, who won the gold medal at the

2018 Winter Olympics The 2018 Winter Olympics ( ko, 2018년 동계 올림픽, Icheon sip-pal nyeon Donggye Ollimpik), officially the XXIII Olympic Winter Games (french: Les XXIIIes Jeux olympiques d'hiver; ko, 제23회 동계 올림픽, Jeisipsamhoe Donggye Ollimpi ...

by "backloading" her free skating program, or placing all her jumps in the second half of the program in order to take advantage of the rule in place at the time that awarded a ten percent bonus to jumps performed during the second half of the program. Also starting in 2018, single skaters could repeat the same two triple or quadruple jumps only in their free skating programs. They could repeat four-revolutions jumps only once, and the base value of the triple Axel and quadruple jumps were "reduced dramatically". As of 2022, jump sequences consisted of two or three jumps, but the second or third jump had to be an Axel. Jump sequences began to be counted for their full value and skaters could include single jumps in their step sequences as choreographic elements without incurring a penalty. Junior men and women single skaters are not allowed to perform quadruple jumps in their short programs. Senior and junior men and senior women must complete either a double or triple Axel jump in their short programs, but junior women must complete a double axel. Male and female junior and senior skaters must include a "maximum of seven jump elements (one of which must be an Axel type jump)" in their free skating programs. Both junior and senior skaters receive no points for jumps performed during their short programs that do not satisfy the requirements, including completing the wrong number of revolutions.

Pair skating

Bundesarchiv Bild 183-1983-0329-027, Barbara Underhill, Paul Martini

Pair teams, both juniors and seniors, must perform one solo jump during their short programs; it can include a double flip or double Axel for juniors, or any kind of double or triple jump for seniors. In the free skating program, for both juniors and seniors, skaters can perform up to three jump combinations or two jump combinations and one jump sequence; a jump combination and jump sequence can consist of the same or another single, double, triple, or quadruple jump. One jump combination or jump sequence can consist of up to three jumps, while the other two can consist of up to two jumps each. A jump sequence starts with any type of jump, immediately followed by an Axel-type jump.Tech Panel, p. 15 Junior pairs, during their short programs, earn no points for the solo jump if they perform a different jump than what is required. Both junior and senior pairs earn no points if, during their free skating programs, they repeat a jump with more than two revolutions.Tech Panel, p. 17 All jumps are considered in the order in which they were performed. If the partners do not execute the same number of revolutions during a solo jump or part of a jump sequence or combination (which can consist of two or three jumps), only the jump with the fewer revolutions will be counted in their score. The double Axel and all triple and quadruple jumps, which have more than two revolutions, must be different from one another, although jump sequences and combinations can include the same two jumps. Extra jumps that do not fulfill the requirements are not counted in the team's score. Teams are allowed, however, to execute the same two jumps during a jump combination or sequence. If they perform any or both jump or jumps incorrectly, only the incorrectly-done jump is not counted and it is not considered a jump sequence or combination. Both partners can execute two solo jumps during their short programs, but the second jump is worth less points than the first. Throw jumps are "partner-assisted jumps in which the woman is thrown into the air by the man on the takeoff and lands without assistance from her partner on a backward outside edge".S&P/ID 2021, p. 111 Skate Canada says, "The male partner assists the female into flight." The types of throw jumps include: the throw Axel, the throw Salchow, the throw toe loop, the throw loop, the throw flip, and the throw Lutz. The throw triple Axel is a difficult throw to accomplish because the woman must perform three-and-one-half revolutions after being thrown by the man, a half-revolution more than other triple jumps, and because it requires a forward takeoff. The speed of the team's entry into the throw jump and the number of rotations performed increases its difficulty, as well as the height and/or distance they create. Pair teams must perform one throw jump during their short programs; senior teams can perform any double or triple throw jump, and junior teams must perform a double or triple toe loop, flip, or Lutz. If the throw jump is not done correctly, including if it has the wrong number of revolutions, it receives no value. Pair teams must perform at least two different throw jumps with a different number of revolutions in their free skating programs. A throw jump is judged as a jump with a higher number of revolution if it is over-rotated more than a quarter revolution; for example, if a pair attempts a double throw jump but over-rotates it, the judges record it as a downgraded triple throw jump.Tech Panel, p. 18

Execution

According to Kestbaum, jumps are divided into eight parts: the set-up, load, transition, pivot, takeoff, flight, landing, and exit. All jumps, except for the Axel, are taken off while skating backward; Axels are entered into by skating forward. Skaters travel in three directions simultaneously while executing a jump: vertically (up off the ice and back down); horizontally (continuing along the direction of travel before leaving the ice); and around. They travel in an up and across, arc-like path while executing a jump, much like the projectile motion of a pole-vaulter. A jump's height is determined by vertical

velocity Velocity is the directional speed of an object in motion as an indication of its rate of change in position as observed from a particular frame of reference and as measured by a particular standard of time (e.g. northbound). Velocity i ...

and its length is determined by vertical and horizontal velocity. The trajectory of the jump is established during takeoff, so the shape of the arc cannot be changed once a skater is in the air. Their body absorbs up to 13–14 g-forces each time they land from a jump, which sports researchers Lee Cabell and Erica Bateman say contributes to overuse injuries and stress fractures. Skaters add variations or unusual entries and exits to jumps to increase difficulty. For example, they will perform a jump with one or both arms overhead or extended at the hips, which demonstrates that they are able to generate rotation from the takeoff edge and from their entire body instead of relying on their arms. It also demonstrates their back strength and technical ability to complete the rotation without relying on their arms. U