Biomechanics of Jumping

BIOMECHANICS OF
JUMPING
Presented by-
Shubham gupta
MPT (Sports) IInd sem

Types Of Jumping
• High jump/
Vertical jump
• Long jump

High Jump
• The high jump is a track and field event in
which competitors must jump over a
horizontal bar placed at measured heights
without the aid of certain devices.
Men's records
World
Javier Sotomayor 2.45 m (8 ft 01⁄4 in)
(1993)
Olympic
Charles Austin 2.39 m (7 ft 10 in) (1996)
Women's records
World
Stefka Kostadinova 2.09 m (6 ft 101⁄4 in)
(1987)
Olympic Yelena Slesarenko 2.06 m (6 ft 9 in) (2004)

Basic Principles Of High Jumping:
• To clear a high jump bar, it is necessary to drive
the center of mass (c.m.) of the athlete to the
largest height possible.
• It is also necessary to move the body in the air in
a way that will allow the athlete to clear a bar set
as close as possible to the peak height reached by
the c.m.
• For a given peak height of the c.m., lowering
some parts of the body makes other parts of the
body go higher.

Technique of high jump
• Techniques have progressed a lot since the
beginning of modern high jumping around
1800.
• And every new technique was named after an
improvement in the bar clearance.

(no technique) legs-up
~1800
If a high jumper remains in a straight vertical position after
taking off from the ground, the height of the bar that the
feet can clear will be far below the peak height of the c.m.
By lifting the legs, the trunk and head get lower,
and the c.m. stays at the same peak height as
before. But the athlete can clear a higher bar.
Legs-up

scissors
The next technique in the evolution of high jumping was the “scissors”, in which the legs are
lifted over the bar in alternation one after the other. The advantage of the scissors technique
is that parts of both legs are below the level of the bar at the peak of the jump. This increases
the height of the pelvis, and therefore the bar height that can be cleared.

Progression Of Bar Clearance Effectiveness
legs-up scissors
~1874

Eastern Cut-off
The scissors was followed by the “eastern cut-off” technique (sometimes called the Lewden
scissors in Europe). In this technique the athlete rotates the trunk into a horizontal position
at the peak of the jump. This lowers the trunk, and therefore lifts the pelvis higher than in
the simple scissors technique. The result is a higher bar clearance. A disadvantage of the
Eastern cut-off is that it requires tremendous flexibility.

Scissors
~1892
Eastern Cut-off

Western Roll
The eastern cut-off was succeeded by the “western roll” technique. In this technique the
athlete cleared the bar on his/her side, with the takeoff leg tucked under the rest of the
body. This technique probably did not improve much the effectiveness of the bar clearance
in relation to the eastern cut-off. However, it also did not require very much flexibility.
Thus, the contribution of the western roll was to provide a reasonably effective bar
clearance for a larger number of high jumpers.

Eastern Cut-off
~1912
Western Roll

Straddle
The western roll was followed by the “straddle” technique. In this technique the athlete
cleared the bar face-down, with the body stretched along the bar. The straddle allowed
parts of the legs to be lower than the bar at the peak of the jump. This allowed the pelvis
to rise to a greater height in relation to the position of the c.m., and therefore improved
the effectiveness of the bar clearance.

Western Roll Straddle
~1930

Dive Straddle
A new variant of the straddle appeared around 1960. It was called the “dive straddle”. In
this technique, at the peak of the jump the athlete’s trunk was set at an oblique angle with
respect to the bar. This allowed the athlete to drop the head and upper trunk below the level
of the bar at the peak of the jump. This raised the hips and the rest of the body, and therefore
allowed the athlete to clear a higher height than with the older (“parallel”) straddle.

Progression of bar clearance effectiveness
Straddle Dive straddle
~1960

Improvements in run-up and takeoff:
• fast run-up
Some athletes used a fast run-up. This allowed them to put the
muscles of the takeoff leg in fast eccentric conditions during the
takeoff phase, which in turn allowed the athlete to exert a larger
vertical force on the ground.
(In “eccentric conditions” the muscles are forced to stretch while
they are trying to shorten. In such conditions the muscles can make
very large forces.)

• fast run-up
• low position at end of run-up
Other athletes ran with the c.m. in a low position in the last
steps of the run-up. This allowed them to have available a long
vertical range of motion for the c.m. during the takeoff phase.
This increased the height of the jump.

• close to vertical at end of takeoff
• fast run-up
Some athletes noticed that a vertical position of the body at
the end of the takeoff increased the height of the jump. This
was also due to an increased vertical range of motion during
the takeoff phase.

• double-arm action
• fast run-up
Other jumpers moved their arms into a backward position
in the last steps of the run-up, and then threw them strongly
forward and upward during the takeoff phase. This allowed
the takeoff leg to exert a larger force against the ground.

• double-arm action
• fast run-up
• straight lead leg action
Still others kicked forward and upward with the lead leg during
the takeoff phase, with a motion similar to a soccer kick:

A completely new technique appeared in the mid-1960’s.
It was invented independently by several different jumpers
who took advantage of the increased safety provided by
foam-rubber landing mats.
In 1968, Dick Fosbury won the
American University (NCAA)
Indoor and Outdoor
Championships using this technique.
Today this technique is called the
“Fosbury-flop”. These athletes
made the bar clearance on their
backs, with the body horizontal
and perpendicular to the bar.
Later that year, Fosbury competed at the Mexico City
Olympic Games and won.

Until Fosbury’s win at the 1968 Olympic Games, there had
been little information on this jumping style. But the Games
were televised live, world-wide. The high jumpers and
coaches in the audience were able to see the new technique
in great detail.
It became clear that the bar clearance was not the
only difference between the “standard” dive straddle and
the Fosbury-flop: Fosbury’s run-up was curved, and his
arm and lead leg actions during the takeoff phase were
weaker than in the straddle.

Straddle Fosbury-flop
bar clearance
on the stomach
bar clearance
on the back
straight run-up curved run-up
strong double-arm actions,
and straight lead leg
weaker arm actions, and
bent lead leg
fast run-up even faster run-up

Progression of bar clearance effectiveness
dive straddle
~1967
Fosbury-flop

The double-arm swing and the straight lead
leg action are backward (counterclockwise)
rotations …

… so they favor the generation of the
counterclockwise rotation generally needed
in the air for the straddle bar clearance.

However, in the Fosbury-flop this would not
be good, because for the Fosbury-flop you
need to make a clockwise rotation in the air.

Phases Of High Jump
• The Approach phase / run-up phase
• The takeoff phase
• The flight or bar clearance phase
• The landing phase

The Approach phase / run-up phase
• The run-up serves as a preparation for the takeoff phase, the
most important part of the jump. The bar clearance technique
is less important. Most bar clearance problems actually
originate in the run-up or in the takeoff phase.
• Most jumpers who use the Fosbury flop technique have a
curved approach run.
• The typical length of the run-up for experienced jumpers is
about 10 strides.
• The first part of the run-up usually follows a straight line,
perpendicular to the plane of the standards, and
• The last four or five strides follow a curve.
• One of the main purposes of the curve is to make the jumper
lean away from the bar at the start of the takeoff phase.

Progression of the run-up
• To start the run-up, some athletes walk a few steps and
then start running, others make a standing start.
• In the early part of the run-up the athlete should follow
a gradual progression in which each stride is a little bit
longer and faster than the previous one.
• After a few strides the high jumper should be running
pretty fast, with long, relaxed strides, very similar to
those of 400/800m runners.
• In the last two or three strides of the run-up the
athlete should gradually lower the hips.
• It must be stressed here that this lowering of the hips
has to be done without a significant loss of running
speed.

Factors to look for in the approach
• 2 or 4 stride lead into a
checkpoint
• non take off foot hits this
checkpoint
• followed by a curved 5 stride
approach to the take off point
• in the last 3 to 4 strides the
athlete is inclined away from
the bar
• final strides to be fast and hips
kept high

Horizontal velocity and height of the cg at
the end of the run-up
• The takeoff phase is defined as the period of time between the instant
when the takeoff foot first touches the ground (touchdown) and the
instant when it loses contact with the ground (takeoff).
• During the takeoff phase the takeoff leg pushes down on the ground. In
reaction, the ground pushes up on the body through the takeoff leg with
an equal and opposite force.
• The upward force exerted on the athlete changes the vertical velocity of
the center of gravity from a value that is initially close to zero to a large
upward vertical velocity.
• The vertical velocity of the athlete at the end of the takeoff phase
determines how high the center of gravity will go after the athlete leaves
the ground.
• To obtain a large vertical velocity at the end of the takeoff phase the
vertical force exerted by the athlete on the ground should be:
• As large as possible, and
• Exerted for as long as possible.

• A fast approach run can help the athlete to exert a larger vertical force on
the ground. This can happen in the following way:
• • When the takeoff leg is planted ahead of the body at the end of the run-
up, the knee extensor muscles try to resist against the flexion of the leg,
but the leg is forced to flex anyway, because of the forward momentum of
the jumper.
• • In this process the extensor muscles of the knee of the takeoff leg are
stretched. It is believed that this stretching produces a stimulation of the
muscles, which in turn aids the forceful extension of the takeoff leg in the
second half of the takeoff phase.
• Therefore, a fast run-up is good or increasing the vertical force exerted
during the takeoff phase.
• To maximize the time during which the vertical force is exerted on the
body it is necessary for the center of gravity to go through a long vertical
range of motion during the takeoff phase. This can be achieved by making
the center of gravity:
• Low at the start of the takeoff phase, and
• High at the end of it.

Arm actions
• The actions of the arms during the takeoff phase are very
important for the outcome of the jump.
• As the arms are accelerated upward during the takeoff
phase, they exert by reaction a compressive force
downward on the trunk.
• This force is transmitted through the takeoff leg to the
ground.
• For a good arm action both arms should swing forcefully
forward and up during the takeoff phase.
• The arms should not be too flexed at the elbow during the
swing - a good elbow angle seems to be somewhere
between 90 degrees of flexion and full extension.

Take off
 Factors to look for on take off:
• take off point is approx. 0.5meters to 0.75meters from the near upright along the bar and out from
the bar
• take off foot is slightly ahead of the athlete's body
• take off foot plant is an active flat down and back action
• take off foot is pointing towards a position halfway between the middle of the bar and the far
upright (10° to 20°)
• take off foot is in alignment with the take off leg
• hips are forward
• inside shoulder is high
• the trunk is upright and leaning slightly back - not leaning towards the bar
• hips are at 45° to the bar and the shoulders at 90°
• there is quick and vigorous movement of free limbs
• the inside shoulder does not drop in towards the bar
• rotation comes from the non jumping side i.e. the free leg and shoulder pulling across the body
• the leg nearest the bar is driven up bent and high at the opposite upright, thigh and foot parallel
with the ground and lower leg vertical
• both arms are swung forwards and upwards with the free leg

Height and vertical velocity of the center of
gravity at the end of the takeoff phase
• The peak height that the center of gravity will reach over
the bar is totally determined at the end of the takeoff
phase.
• It is determined by the height of the center of gravity and
by its vertical velocity at the end of the takeoff phase.
• At the instant that the takeoff foot loses contact with the
ground the center of gravity of a high jumper is usually at a
height somewhere between 70 percent and 75 percent of
the standing height of the athlete.
• This means that tall high jumpers have a built-in advantage.
Their center of gravity’s will generally be higher at the
instant they leave the ground.

Flight
Once off the ground factors to look for in the flight:
• inside knee stays up at bar level
• heels are pulled back towards the head (arching the back)
• knees bent and wide apart
• arms in a crucifix position or held by the side
• head back and looking towards the far back corner of the
mat (forces the hips to stay high)
• once the hips are over the bar the legs are snapped straight
from the knees
• landing on the shoulders

Peak height of the center of gravity and
outcome of the jump
• If an athlete can’t clear the bar when the center of
gravity goes 6cm higher than the bar, we consider this
to be a very ineffective bar clearance technique.
• If the center of gravity needs to go between 3 to 6cm
higher than the bar to clear it, we consider this a
reasonable bar clearance technique.
• If the athlete is able to clear the bar when the center of
gravity goes no higher than 2cm over the bar (or if the
center of gravity passes under the bar), we consider
this a very effective bar clearance technique.

The most usual reasons for an ineffective
bar clearance are:
• Taking off too close or too far from the bar
• Insufficient amount of somersaulting angular
momentum
• Poor arching, and
• Bad timing of the arching/un-arching process.

Takeoff distance
• The distance between the toe of the takeoff foot and the plane of the bar and the standards is
called the “takeoff distance”.
• The value of this distance is very important, because it determines the position of the peak of
the jump relative to the bar:
• If an athlete takes off too far from the bar, the center of gravity will reach its maximum height
before crossing the plane of the standards and the jumper will probably fall on the bar.
• If the athlete takes off too close to the bar, there will be a large risk of hitting the bar while the
center of gravity is on its way up, before reaching its maximum height.
• Athletes who run faster in the final strides of the run-up will generally have more horizontal
velocity left after takeoff, thus they will travel through larger horizontal distances after the
completion of the takeoff phase than slower jumpers and will also need to take off farther from
the bar in order for the center of gravity to reach its maximum height directly over the bar.
• If the bar was hit a long time after the takeoff, this probably means that the bar was hit as the
athlete was coming down from the peak of the jump, implying that the athlete took off too far
from the bar. In that case the athlete should move the starting point of the run-up slightly closer
to the bar.
• If the bar was hit very soon after the takeoff, this probably means that the bar was hit while the
athlete was still on the way up toward the peak of the jump, implying that the takeoff point was
too close to the bar. In that case the athlete should move the starting point of the run-up
slightly farther from the bar.

Angular momentum
• In order to perform a proper layout over the bar the athlete needs to
rotate after leaving the ground. For this rotation, the jumper needs a
certain amount of angular momentum (also called rotary momentum).
• Practically all of this angular momentum is produced during the takeoff
phase. No angular momentum can be obtained after the athlete leaves
the ground.
• The bar clearance technique of a Fosbury flop can be described roughly as
a twisting backward somersault. The twist, that makes the athlete turn the
back to the bar during the ascending part of the flight path, is generated
mainly by:
• Swinging the lead leg up and somewhat away from the bar during the
takeoff phase, and also
• The active turning of the shoulders in the desired direction of the twist
before the end of the takeoff phase.
• These actions create angular momentum about a vertical axis (HT).

The somersault, which will make the shoulders go down
while the knees go up, results from two different
components:
1. Forward somersaulting angular momentum (HF)
• During the takeoff phase, angular momentum is produced about a
horizontal axis perpendicular to the final direction of the run-up.
• This forward rotation is similar to the one that is produced when a
person hops off from a moving bus while facing the direction of
motion of the bus. After the feet hit the ground the tendency is to
rotate forward and fall flat on one’s face. This can be described as
angular momentum produced by checking of a linear motion.
• The forward somersaulting angular momentum can be affected by
the arm and lead leg actions.
• Wide swings of the arms and of the lead leg can help the athlete to
jump higher, but they also generally imply backward rotations of
these limbs, which can reduce the forward somersaulting angular
momentum of the body.

2. Lateral somersaulting angular momentum (HL)
• During the takeoff phase angular momentum is also produced
about a horizontal axis in line with the final direction of the run-
up.
• From a rear view of an athlete who takes off from the left leg,
this angular momentum component appears as a clockwise
rotation.
• If the jumper made use of a straight run-up, in a rear view the
athlete would be upright at touchdown and leaning toward the
bar at the end of the takeoff phase. The production of angular
momentum would thus cause a reduction in the vertical range of
motion of the center of gravity during the takeoff phase.
• However, if the athlete uses a curved run-up, the initial lean of
the athlete is toward the left at the end of the takeoff phase.
• This favors a large vertical range of motion of the center of
gravity during the takeoff phase and thus permits greater lift
than if a straight run-up were used.
• One of the main purposes of the curve of the approach run is to
achieve this lateral lean at the end of the run-up, i.e., at the start
of the takeoff phase.

Adjustments in the air
• other factors that can also have some effect
on the rotation:
• By speeding up the rotation of some parts of
the body, other parts of the body will slow
down as a compensation, and vice versa.
• Another way in which rotation can be
changed is by altering the “moment of
inertia” of the body.

Technical Analysis
• Approach Phase
Tan and Yeadon (2004) Suggest that a tightening curve towards the end of the approach
will lead to an increased inward lean velocity. This is important as the greater the
velocity before takeoff the more chance of success.
Backward lean angle and inward lean angle are the
angles made with the vertical by projections of the foot – centre of mass line FG
on vertical planes parallel and perpendicular to the horizontal velocity v.

Technical analysis
Several coaches
have suggested
that the curved
approach is useful
in developing this
somersaulting
motion during
the take-off
phase.
Tan and Yeadon
(2004) suggest that
on approach the
inward lean angle
should be
approximately 300
then decreased to 00
by the final foot take
off. The tightening of
this approach curve
leads to an inwards
lean rotational
velocity which helps
develop the
somersaulting
motion.

Approach Phase
SuccessfulUnsuccessful
On approach both attempts shows very little difference in inward lean angle
although the successful jump has a larger lean angle therefore can create a
larger angular velocity which will develop a more efficient somersault motion.
This may be the reason the jump is successful.
27.5 31.8

Technical Analysis Takeoff
• Depena (1980) suggested that the main purpose of the inward lean on approach is
so, the performers are positioned leaning away from the bar. This will create a
successful attempt.
• Tan and Yeadon (2004) recommend that at take off the inward lean angle should
decrease from 300 to 00. This will create a vertical takeoff velocity and slight
anglular velocity to travel up and over the bar.

Technical analysis
• Take-off
Lees et al (2000) suggest that the arms in the take-off phase have a greater influence
on performance than the lead leg.
The inside shoulder should not drop in towards the bar and both arms should be
swung upwards with the free leg (Mac 1997).
Grieg and Yeadon (2000) explain from their
research that at leg plant (before take off) The
greater the angle at the knee the higher the
jump height.
Leg plant vs. Jump Height

Takeoff Phase
Unsuccessful Successful
In both attempts at immediate toe off, Stefan Holm converts his
inward lean to a near vertical takeoff. This is supported by Tan and
Yeadon (2004) as a successful takeoff.
4.7 4.9

Takeoff Phase 2
Unsuccessful Successful
After immediate takeoff in the unsuccessful jump, Stefan Holms lowers his
shoulder therefore his arm bends making his approach angle to the bar a
lot greater. This makes his overall attempt lower and consequently he hits
the bar making it an unsuccessful jump.
The successful jump demonstrates what the literature suggests. Stefan
keeps his vertical angle by not dropping his shoulder and has a greater
angular velocity which creates height and a well developed somersault
rotation. The arms are one of the most important aspects and this is the
key difference between the two techniques which allows Stefan to
succeed.
8.2 2.7

Kinematic and kinetic of high jump

• The high jumper’s takeoff occurred too far out
from the bar but he adjusted his projection angle
to peak over the bar.
• The high jumper’s CM was at its apex during bar
clearance. The CM passed 18 cm below the
2.28 m bar height.
• The jumper utilized a hip hike- hip drop
maneuver to facilitate leg clearance

HIGH JUMP ANALYSIS
• First stage: a run along a straight line. During the first
stage, the athlete runs along a straight line (or linear
trajectory).
• It’s important for the athlete to control their horizontal
velocity and other factors: During running and jumping…
forces must be applied to and from a stable base to
produce efficient movement.
• Note that average length of this segment of the high
jump is about 11 meters. That is,
𝑣 = 𝑑/𝑡 or 𝑣 = 11/𝑡
where 𝑣 is the athlete’s speed, 𝑑 is the distance (taken
here to be 11 meters as explained above), and 𝑡 is the
time.

• Second stage: a run along an arc of a circle. The athlete
changes his or her trajectory during the second stage.
• Instead of running along a straight line, the athlete runs
along a trajectory that we approximate by an arc of a circle.
• Here, the centrifugal force plays a critical role. This force
allows the jumper to clear the bar horizontally. The
centrifugal force is calculated using the following equation
𝐹 = 𝑚 𝑣2/𝑟
where 𝑚 is the athlete’s mass, 𝑣 is his/her speed, and 𝑟 is
the radius of the trajectory
• The athlete may jump high enough, but if the angular
momentum is off during the second stage of the jump, then
the athlete will either (a) hit the bar off during the upward
ascent or (b) hit the bar off during the descent.

• Third stage: projectile motion of a jump. The third stage of the high
jump is the actual jump that we model as a projectile motion.
• During this stage, the jumper ascends over the bar, reaches his or hers
maximum height, and then begins the descent onto the high jump mat.
The trajectory of this jump is a parabola.
• The equation we use to model the athlete’s trajectory is
𝑦 = 𝑦0 + 𝑣𝑖𝑡 +𝑔 𝑡2/2
where 𝑦0 is the initial distance of the athlete’s center of mass from the
ground, 𝑣𝑖 is the initial velocity, 𝑔 is the standard gravity, and 𝑡 is time.
• The initial velocity in the above formula can be determined using the
equation
𝑣𝑖2 = 𝑣ℎ2 + 𝑣 𝑣2
where 𝑣ℎ are the horizontal velocity and 𝑣 𝑣 is the vertical velocity of the
athlete before the jump.

• Analysis suggests that during the first two stages
of the jump, the athlete should attain the correct
angular momentum to clear the bar during the
jump.
• Thus the jumper should not try to be at his or her
full velocity.
• A high velocity of the run is good as long as it is
controllable and paired with an even greater
vertical velocity generated by the jump.
• Another important recommendation for high
jumpers is to kick their feet up after they reach
the maximum height.

COMMON INJURIES IN HIGH JUMP
The most frequently injured parts of the body with
the top male and female high jumpers

Causes of injury
Foot
• the activities that caused ankle eversion or excessive
dorsal flexion movement
• frequent walk, run or skips on tiptoes, especially with
an excess load
• extreme stretching of the Achilles tendon
• insufficient/exaggerated pronation of the sole arising
from the unbalanced part of the LL
Shank
• injured calf muscle
• overuse fracture

Knee
• Acute inflammation of bursa in the area above or
below the kneecap as well as a chronic strained knee
• Tendinitis
• Injuries during fitness activities – mainly repeated half
knee bends and knee bends, often with a heavy load
Spine
• injuries to discs caused by repeated overload
• the spondylolisthesis (the shift of the last lumbar
vertebra against the sacral bone forward as a
consequence of the action of mechanical tensions)

Causes of injury
• high values of reaction forces at the take-off,
• inadequate training load,
• unbalanced fitness training (especially with
the high jumpers who are beginners),
• imperfect technique of the take-off,
• anatomical disposition to injuries.

High value of reaction forces
• In the high jump the LL are burdened with a time
variable force that results from contact with the
ground (the influence of weight and inertial
forces) and from the action of muscles.
Inadequate training load
• The athlete makes efforts to achieve higher
performances, which means a constant increase
of the training stress. In this way the volume1 and
particularly, with advanced high jumpers, the
intensity of the demanding kinetic activities
increases.

 Unbalanced fitness training
• experienced high jumpers have specific parts of their bodies that
are prone to injuries and augment harmful influence or vice versa;
certain parts of their bodies are prone to injuries far less than the
other parts of their bodies.
• It is assumed that the only alternative and the only possibility of
preventing injuries or improving performance constantly is to
enhance the overall fitness level.
 Imperfect take-off technique
• The primary element of the take-off is to step on the forepart of the
sole of the take-off leg quickly.
• Therefore, during the studies, the demanding technique of placing
the sole on the ground in the absorption phase (amortization) was
followed closely and the total time of contact of the foot with the
ground was analysed in detail.
• The talented beginner high jumpers consider the high jump to be a
natural activity. The augmented volume of repetitions will show
that the takeoff leg is the main part of the demanding dynamic
explosive kinetic activity.

Anatomical predisposition to injuries
• Following the take-off, top-level high jumpers have a
specific anatomical structure, often power unbalanced.
Some parts of their bodies are less supple, flexible and
elastic – all of which leads to a predisposition to
injuries.
• In general, differently balanced parts of the LL, e.g. the
foot (namely the foot sole turned inward excessively
relative to the longitudinal axis of the foot), the one-
sided lowering of the pelvis, the wrong anterior-
posterior attitude of the pelvis or the differently
flexible Achilles tendons, belong to anatomically
questionable parts.
• the pronation of the foot causes many problems.
• An inflexible Achilles tendon may be the primary cause
of the LL problems.

Long jump
• The long jump (historically called the broad
jump) is a track and field event in which
athletes combine speed, strength, and agility
in an attempt to leap as far as possible from a
take off point.
Men's records
World Mike Powell 8.95 m (29 ft 41⁄4 in) (1991)
Olympic
Bob Beamon 8.90 m (29 ft 21⁄4 in) (1968)
Women's records
World
Galina Chistyakova 7.52 m (24 ft 8 in)
(1988)
Olympic Jackie Joyner 7.40 m (24 ft 31⁄4 in) (1988)

• The basic technique used in long jumping has remained unchanged
since the beginning of modern athletics in the mid-nineteenth century.
• The athlete sprints down a runway, jumps up from a wooden take-off
board, and flies through the air before landing in a pit of sand.
• A successful long jumper must, therefore, be a fast sprinter, have strong
legs for jumping, and be sufficiently coordinated to perform the
moderately complex take-off, flight, and landing maneuvers.
• To produce the greatest possible jump distance the athlete must reach
the end of the run-up with a large horizontal velocity and with the take-
off foot placed accurately on the take-off board.
• During take-off the athlete attempts to generate a large vertical velocity
while minimizing any loss of horizontal velocity, and in the flight phase
the athlete must control the forward rotation that is produced at take-
off and place their body in a suitable position for landing.
• During the landing the athlete should pass forward of the mark made
by their feet without sitting back or otherwise decreasing the distance
of the jump.

Phases of long jump
• Approach
• Take‐off
• In the Air
• Landing

Approach / Run-up
• The run-up phase is crucial in long jumping; it is
impossible to produce a good performance
without a fast and accurate run-up.
• The three main tasks of the athlete during the
run-up are:
• to accelerate to near-maximum speed, lower the
body during the final few steps
• bring it into position for take-off, and
• place the take-off foot accurately on the take-off
board.

Run-up velocity
• In long jumping, the distance achieved is strongly determined by
the athlete’s horizontal velocity at the end of the run-up.
• To produce a fast run-up, most long jumpers use 16–24 running
strides performed over a distance of about 35–55 m.
• By the end of the run-up the athlete reaches about 95–99 per cent
of their maximum sprinting speed.
• Long jumpers do not use a longer run-up length that gives 100 per
cent sprinting speed because the advantage of a faster run-up
speed is outweighed by the increased difficulty in accurately hitting
• the take-off board.
• Faster athletes tend to use a longer run-up because it takes them
longer to build up to their maximum sprinting speed.
• Most long jumpers start their run from a standing position with one
foot forward of the other.
• Some athletes prefer to take several walking strides onto a check
mark before accelerating. However, this technique is believed to
produce a less consistent velocity profile and hence a less accurate
run-up.

Run-up accuracy
• To produce the best possible jump distance, a long jumper must place
their take-off foot close to, but not over, the take-off line that is marked by
the front edge of the take-off board.
• The long jump run-up has two main phases;
• an acceleration phase during which the athlete produces a stereotyped
stride pattern; and
• a ‘zeroing-in’ phase during which the athlete adjusts their stride pattern to
eliminate the spatial errors that have accrued during the first phase.
• During the last few strides before take-off, the athlete uses their visual
perception of how far away they are from the board as a basis for
adjusting the length of their strides.
• Top long jumpers start using a visual control strategy at about five strides
before the board and are able to perform the stride adjustments with only
a small loss of horizontal velocity.
• Athletes of lesser ability tend to have a greater accumulated error and
anticipate their stride adjustment later than highly-skilled jumpers.
• Many long jumpers use a checkmark at 4–6 strides before the board so
that their coach can monitor the accumulated error in the first phase of
the run-up.

Transition from run-up to take-off
• Skilled long jumpers maintain their normal sprinting action up until about
two to three strides before take-off.
• The athlete then begins to lower their centre of mass (COM) in
preparation for the take-off.
• A low position into the take-off is necessary to give a large vertical range
of motion (ROM) over which to generate upwards velocity.
• The athlete lowers their COM to the required height and tries to keep a
flat trajectory in the last stride before take-off.
• This ensures that the athlete’s COM has minimal downward vertical
velocity at the instant of touchdown and so the upwards vertical impulse
exerted by the athlete during the take-off produces the highest possible
vertical velocity at the instant of take-off.
• The entry into the take-off is usually performed using a ‘pawing’ action,
where the take-off leg is swept down and back towards the athlete.
• The take-off foot has a negative velocity relative to the athlete’s COM, but
the velocity of the foot relative to the ground is not quite reduced to zero
(about 4–5 m/s).
• This ‘active’ landing technique is believed to reduce the braking force
experienced by the athlete during the initial stages of the take-off.

Take-off
• Although long jump performance is determined primarily by the athlete’s
ability to attain a fast horizontal velocity at the end of the run-up, the
athlete must also use an appropriate take-off technique to make best use
of this run-up velocity.
• Long jumpers place their takeoff foot well ahead of their COM at
touchdown to produce the necessary low position at the start of the take-
off.
• The jumper’s body then pivots up and over the take-off foot, during which
time the take-off leg rapidly flexes and extends.
• Long jumping is essentially a projectile event, and the athlete wishes to
maximize the flight distance of the human projectile by launching it at the
optimum take-off velocity and take-off angle.
• In launching the body into the air, the athlete desires a large horizontal
velocity at take-off to travel forward and a large vertical velocity to give
time in the air before landing back on the ground.
• In the long jump, the optimum take-off technique is to run up as fast as
possible and plant the take-off leg at about 60–65˚ to the horizontal.

Take-off mechanism
• Just before touchdown the athlete pre-tenses the muscles of the take-off leg.
The subsequent bending of the leg during the take-off is due to the force of
landing, and is not a deliberate yielding of the ankle, knee, and hip joints.
• Flexion of the take-off leg is unavoidable and is limited by the eccentric strength
of the athlete’s leg muscles.
• Maximally activating the muscles of the take-off leg keeps the leg as straight as
possible during the take-off. This enablesthe athlete’s COM to pivot up over the
foot, generating vertical velocity via a purely mechanical mechanism.
• The knee extension phase makes only a minor contribution to the generation of
vertical velocity, and the rapid plantar flexion of the ankle joint towards the end
of the take-off contributes very little to upward velocity.
• Long jumpers spend a lot of time on exercises to strengthen the muscles of their
take-off leg. Greater eccentric muscular leg strength gives the athlete a greater
ability to resist flexion of the take-off leg, which enhances the mechanical pivot
mechanism during the take-off and hence produces a greater take-off velocity.

• The stretch-shorten cycle, where the concentric phase of a
muscle contraction is facilitated by a rapid eccentric phase,
does not play a significant role in the long jump take-off.
Rather, fast eccentric actions early in the take-off enable the
muscles to exert large forces and thus generate large gains in
vertical velocity.
• In long jumping, the gluteus maximus is active isometrically at
first and then concentrically; the hamstrings are active
concentrically throughout the take-off; rectus femoris acts
either isometrically at first then eccentrically or eccentrically
throughout the take-off; and the vasti, soleus, and
gastrocnemius act eccentrically at first and then
concentrically.
• The explosive extension of the hip, knee, and ankle joints
during the last half of the takeoff is accompanied by a
vigorous swinging of the arms and free leg.

Take-off angle
• It is well known that take-off angles in the long jump are substantially less than the 45˚
angle that is usually proposed as the optimum for a projectile in free flight.
• Video measurements of world-class long jumpers consistently give take-off angles of
around 21˚.
• The notion that the optimum take-off angle is 45˚ is based on the assumption that the
take-off velocity is constant for all choices of take-off angle. However, in the long jump,
as in most other sports projectile events, this assumption is not valid.
• The take-off velocity that a long jumper is able to generate is substantially greater at low
take-off angles than at high take-off angles and so the optimum take-off angle is shifted
to below 45˚.
• From a mathematical perspective the athlete’s take-off velocity is the vector sum of the
horizontal and vertical component velocities, and the take-off angle is calculated from
the ratio of the component velocities.
• A take-off angle of 45˚ requires that the horizontal and vertical take-off velocities are
equal in magnitude.
• The maximum vertical velocity an athlete can produce is about 3–4 m/s (when
performing a running high jump), but an athlete can produce a horizontal take-off
velocity of about 8–10 m/s through using a fast run-up.
• By deciding to jump from a fast run-up, the athlete produces a high take-off velocity at a
low take-off angle.

Take-off forces
• During the take-off the athlete experiences a ground reaction force (GRF) that tends to
change the speed and direction of the athlete’s COM.
• The horizontal force during the take-off is predominantly a backwards braking force, and
only for a very short time at the end of the takeoff does it switch over to become a
forwards propulsive force.
• Because the braking impulse is much greater than the propulsive impulse, the athlete’s
forward horizontal velocity is reduced during the take-off (by about 1–3 m/s).
• The vertical GRF exerted on the athlete produces the athlete’s vertical take-off velocity.
The vertical force initially acts to reverse the downward velocity possessed by the
athlete at touchdown, and then accelerates the athlete upwards.
• The athlete always experiences a slight reduction in upwards velocity in the last instants
before take-off. This decrease occurs because the vertical force must drop down to zero
at the instant of take-off.
• For a short time before take-off the vertical GRF is less than body weight and is therefore
not enough to overcome the gravitational force on the athlete.
• Both the horizontal and vertical components of the GRF display a sharp impact peak at
touch down when the takeoff leg strikes the ground and is rapidly reduced to near zero
velocity.

The flight through the air
• During the flight phase, most long jumpers either adopt a ‘hang’
position or perform a ‘hitch-kick’ movement (a modified running-in-
the-air action).
• In both techniques the athlete’s actions are designed to control the
forward rotation that is imparted to the body at take-off and hence
allow the athlete to attain an effective landing position.
• Long jumpers choose their flight technique according to the
amount of angular momentum they generate during the take-off
and the time they have available before landing.
• Many coaches recommend the hang technique for athletes of lesser
ability, who usually generate a lower angular momentum during the
take-off and spend less time in the air.
• The hitch-kick is recommended for better athletes, who usually
generate a higher angular momentum during the take-off and have
a longer flight time.

Long Jump Styles
The Stride Jump
• In the stride jump style the athlete maintains the take off
position for as long as possible and only as the athlete comes
into land does the take off leg join the free leg for a good
landing position.

The Hang Style
• On take off the athlete drops the free leg to the vertical which
is then joined by the take off leg. The arms go overhead to
slow down the rotation about the athlete's centre of gravity.
The legs are then lifted upwards and forwards whilst lower
the trunk. The arms swing past the legs during the landing
phase to ensure a good leg shoot.

The Hitch-Kick
• Following take off the free leg is straightened and swung back
and down as the take off leg folds up beneath the hips and
comes forward bent. The take off leg then continues forward,
straightening for landing. The free leg completes its backward
swing behind the hip and then folds up and comes forwards
bent, to join the take off leg ready for landing.

Landing
• Towards the end of the flight phase the athlete
prepares for landing by lifting their legs up and
extending them in front of the body.
• The goal of the landing is to create the greatest
possible horizontal distance between the take-off
line and the mark made by the heels in the sand.
• The landing technique should not result in the
athlete falling backwards into the pit or otherwise
producing a mark that is closer to the take-off
board than that made by the heels.

• The athlete’s jump distance is measured from the take-off line to
the nearest mark made by the athlete in the landing area.
• Jump distance may be considered as the sum of the take-off
distance, the flight distance, and the landing distance:
djump = dtake-off + dflight + dlanding
• During the flight phase of the jump the effects of gravity are
much greater than those of aerodynamic forces and so the
jumper may be considered as a projectile in free flight.
• The trajectory of the athlete’s COM is determined by the
conditions at take-off, and the flight distance is given by:
• where v is the take-off velocity, θ is the take-off angle, and g is the
acceleration due to gravity.
• Here, the relative take-off height, h, is given by:
h = htake-off – hlanding
Flight distance equation

Kinematic and kinetics of long jump
• The two most important factors in the long jump are speed
and elevation. This is exemplified by the fact that two of the
greatest long jumpers in history, Jesse Owens and Carl Lewis,
were also the greatest sprinters of their times.

Optimum launch angle
• It is well known that, in the absence of air resistance, the
optimum launch angle of a projectile for maximum range on a
horizontal plane is 45.
• However, this is not applicable to the long jump, where the
jumper has to launch himself at the expense of a part of his
translational kinetic energy before takeoff.

• Let v0 be the initial speed of the jumper before takeoff;
v1 the launch speed; and the launch angle of the
jumper. The total energy before takeoff is then
E0 = ½mv0 2, which is of translational kinetic form.
• A fraction gamma γ of this energy is wasted as heat
and sound.
• Another part, E, is converted into the energy of vertical
motion: E = ½mv1 2 sin2.
• The translational kinetic energy of the jumper after
take off is E1 = ½mv1 2. By the law of conservation of
energy, we have E1 = E0 – γE0 – E
• simplifying, we obtain
• The range R of the projectile on a horizontal plane is
obtained from elementary kinematics:

• Differentiating twice:
• Setting dR/d = 0, we obtain the optimum
launch angle on a horizontal plane:
αm = ½ cos–1(1/3) =35.26degree
• If is the angle of landing, then h = a – bsinβ. In
this situation, the distance of the long jump is
given by:
where L = bcosβ
• On substituting v1
with B = h/A.

Common injuries in long jump
• There are many types of jumping injuries which may cause the
athlete pain, and these could include:
• Stress fracture of feet or shins
• Achilles tendinitis
• Plantar fasciitis
• Anterior compartment syndrome
• Medial shin splints
• Chondromalacia patella
• Patella tendinitis
• Spondylolysis
• Spondylolisthesis
• Annular bulge

Cause of Jumping Injuries
• high ground reaction forces,
• overuse (especially in elite athletes),
• poor physical preparation (especially in novice
athletes),
• poor technique and
• anatomical predisposition

High Ground Reaction Forces
• This will cause anatomical structures such as fascia,
ligaments, tendons and bones to bear the load during
high stress activities such as jumping. Whilst the
efficient use of higher ground reaction forces are useful
in a performance aspect, in an injury prevention
viewpoint, excessive amounts of jumping on a hard
surface will eventually lead to injury.
Overuse
• To get an athlete to perform at the highest level, it is a
common coaching practice that high intensity jumping
activities are performed in high volume.

 Poor Physical Preparation
• The novice athlete is at an increased risk of developing jumping
related injuries, as their conditioning level is typically too low for
frequent high intensity jumping.
 Poor Technique
• Landing on a flat foot in most jumping exercises is essential to avoid
injury. You may have already noticed however, that the athlete has
shorter contact times when landing on the ball of the foot during a
depth jump, but doing this type of jump with any volume will cause
injury. For this reason, it is imperative that the coach ensures that
good technique is used before a large of number of repetitions are
attempted.
 Anatomical Predisposition
• Some athletes may have a particular anatomical structure, muscle
imbalance or inflexibility that will predispose them to injury. For
example, an athlete may have a congenitally fused intervertebral
disc that will tend to cause back problems, or an athlete may have
some form of foot structure which may predispose the athlete to a
navicular stress fracture.

Injury rehabilitation
 Ankle
• Using theratubing to perform ankle inversion, eversion and
dorsiflexion exercises
• Using an ankle board to perform various exercises
• Walking sideways across a hill
• Walking on the toes, heels, inside and outside of the feet
• Stretching the achilles tendon and strengthening the
plantarflexors
 Knee
• squatting : it is not just a strength building exercise, but it
could be an injury prevention exercise as well. By
controlling the downward (eccentric) phase of the squat
the patella tendon is strengthened.
• VMO activity is increased by squatting to around parallel.

Hip and Back
• Hip Abductors, that is the middle gluteal muscles
(gluteus medius and minimus) act to stabilise the
pelvis against excessive lateral pelvic whilst in
single limb weight bearing.
• Hip abduction exercises using theraband and
maybe even pulleys in the gym will exercise these
muscles.
• To prevent back injuries such as spondylolysis,
spondylolisthesis and annular bulge the back and
abdominals musculature needs to be well
conditioned.

Jumping Injuries
• Achilles Tendonitis / Tendinitis
• Anterior Ankle Impingement
• Bursitis Knee
• Degenerative Disc Disease
• Femoroacetabular Impingement
(FAI)
• Gluteal Tendinopathy
• High Ankle Sprain
• Stress Fracture Feet
• Knee Arthritis
• Neck Arm Pain
• Hip Labral Tear
• Plantar Fasciitis
• Plica Syndrome
• Severs Disease
• Sprained Ankle

Injury prevention tips
• Avoid training when you are tired
• Increase your consumption of carbohydrate during periods of heavy training
• Increase in training should be matched with increases in resting
• Any increase in training load should be preceded by an increase in
strengthening
• Treat even seemingly minor injuries very carefully to prevent them becoming
a big problem
• If you experience pain when training STOP your training session immediately
• Never train hard if you are stiff from the previous effort
• Pay attention to hydration and nutrition
• Use appropriate training surfaces
• Check equipment is appropriate and safe to use
• Introduce new activities very gradually
• Allow lots of time for warming up and cooling off
• Check over training and competition courses beforehand
• Train on different surfaces, using the right footwear
• Monitor daily for signs of fatigue, if in doubt ease off.

Biomechanics of Jumping

Recomendados

Recomendados

Más contenido relacionado

La actualidad más candente

La actualidad más candente (20)

Similar a Biomechanics of Jumping

Similar a Biomechanics of Jumping (20)

Último

Último (16)

Biomechanics of Jumping