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analysis of jumping mechanics for each technique and factors influencing
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Biomechanics of Biomechanics of JumpingJumping
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Mechanical FactorsMechanical Factors
Speed at takeoff
Height at takeoff
Angle at takeoff
Balance and rotations that occur
during flight
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Speed at TakeoffSpeed at Takeoff Influenced by 2 distinct forces
from run-up to takeoff Horizontal component Vertical component
To slow horizontal while producing vertical
Gradual acceleration progression Constant increase in both SF and SL
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Speed at TakeoffSpeed at TakeoffProblems of slowing
Negative foot speed
Braking with takeoff foot too far back on heel
Allowing hips to be too slow in running position
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Height at takeoffHeight at takeoff High CG means athlete remains
airborne longer
3 techniques that aid in raising CG
Run as tall and erect as possible
Shortening the last stride
High body velocity at takeoff
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Angle at TakeoffAngle at Takeoff
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Angle at TakeoffAngle at Takeoff
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Angle at TakeoffAngle at Takeoff
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Balance and RotationsBalance and RotationsRotational speed increases or decreases as lever length changes
Lengthening/shortening arms, legs or trunk
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Jumping EventsJumping Events
To obtain a maximum displacement
of CG in a given direction
Long jump
Triple jump
High jump
Pole vault
Horizontal direction
Vertical direction
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Long JumpLong Jump
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Long JumpLong Jump
Consist of 4 consecutive parts
Run-up
Takeoff
Flight
Landing
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Basic ConsiderationsBasic Considerations Takeoff distance
Distance between front edge of takeoff board and CG at takeoff
Flight distance Distance that CG travels
Landing distance Distance between CG at landing and
marks on sand Ratio – 3.5% :88.5% :8%
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Distance
Flight distanceTakeoff distance Landing distance
Height of takeoff
Speed of takeoff
Angle of
takeoff
Air resistance
Accuracy of takeoff
physics Body position at takeoff
Body position at touchdown
Action on
landing
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ApproachApproach To get athlete to optimum position
for takeoff
Length of run-up depends on Sprinting velocity
Ability to maintain stride’s pattern
Last 3-4 strides, change in body
position
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TakeoffTakeoff To obtain vertical velocity while
retaining as much horizontal velocity
as possible
Little flexion to cushion shock of
impact
To position leg for vigorous extension
CG moves forward over and beyond
takeoff foot
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FlightFlight To assume optimum body position
for landing
There are 3 in-the-air techniques
Sail technique
Hang technique
Hitch-kick technique
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Sail TechniqueSail Technique
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Hang TechniqueHang Technique
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Hitch-Kick TechniqueHitch-Kick Technique
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LandingLanding
Correct landing
Incorrect landing
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Triple JumpTriple Jump
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Basic ConsiderationsBasic Considerations Consist of 3 phases
The hop The step The jump
10:7:10 for beginner 10:8:9 for top performers Flat technique (low hop and step,
high jump) 7:6:7
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The HopThe Hop
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The HopThe Hop Flat to lower CG
Load up thigh muscles to provide
supercontraction and to minimize
ground contact duration
Trunk remains upright
Extending arms bw to minimize fw
rotation during flight
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The StepThe Step
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The StepThe Step
To maintain horizontal speed,
balance during flight and landing
To control forward rotations
Using double-arm style
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The JumpThe Jump
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Single arm actionSingle arm action
The arm opposite the free leg
drives forward and up to shoulder
level
The angle at the elbow should be
between 80 and 110 degrees
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Double arm actionDouble arm action The lead arm crosses slightly in front of the
body on penultimate step of approach phase
At the take-off step, arm pauses next to the body
As the take-off foot contacts the ground, both arms drive forward and up to shoulder height
The angle of the arms at the elbows > 90 degrees to create a more powerful impulse forward
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High JumpHigh Jump
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Basic ConsiderationsBasic Considerations
Consists of 3 separate heights
H1 – height at takeoff
H2 – height during flight
H3 – difference between max height
and height of bar
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Height
H2H1 H3
Vertical Velocity at
takeoff
Vertical Velocity at takeoff
Vertical Impulse
Vertical Forces exerted at takeoff
Time of takeoff
Body Position
at takeoff
Physics Body Position at
peak
Movements over bar
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ApproachApproach
There are 3 methods of
performing approach run
Fosbury’s original 8-step curved
J approach
Hook approach
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Fosbury’s Original 8-step Fosbury’s Original 8-step CurvedCurved
Allow to lean away from barBe vertical at takeoff
But ;Unable to produce high speedUnable to show consistency of momentum
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J ApproachJ ApproachEasy to establish momentumConstant tempo accelerationConstant distant and curveExact placement of each footExact takeoff spot with lateral lean away from bar
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Hook ApproachHook Approach Easy, smooth
transition Momentum,
speed and lean happen gradually
But ; May get out too
wide
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TakeoffTakeoffFw and uw swing of
lead legs and arm(s)
Increase magnitude
of vertical force
Impart angular
momentum to body
Increase height of
CG at takeoff
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Bar ClearanceBar Clearance
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bar height cleared
peak heightreached by centerof mass (c.m.)
effectiveness ofbar clearance
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progression of bar clearance effectiveness
(no technique) legs-up
~1800
If a high jumper remains in a straight vertical position aftertaking off from the ground, the height of the bar that thefeet 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.
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progression of bar clearance effectiveness
legs-up scissors
~1874
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progression of bar clearance effectiveness
scissors
~1892
eastern cut-off
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progression of bar clearance effectiveness
eastern cut-off
~1912
western roll
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progression of bar clearance effectiveness
western roll straddle
~1930
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progression of bar clearance effectiveness
straddle dive straddle
~1960
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progression of bar clearance effectiveness
dive straddle
~1967
Fosbury-flop
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straddle Fosbury-flop
bar clearanceon the stomach
bar clearanceon the back
straight run-up curved run-up
strong double-arm actions,and straight lead leg
weaker arm actions, andbent lead leg
fast run-up even faster run-up
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Straddle Fosbury-flop
www.***.netThe double-arm swing and the straight leadleg action are backward (counterclockwise)rotations …
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… so they favor the generation of thecounterclockwise rotation generally neededin the air for the straddle bar clearance.
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However, in the Fosbury-flop this would notbe good, because for the Fosbury-flop youneed to make a clockwise rotation in the air.
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Fosbury-flop
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LandingLanding
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Pole VaultPole Vault
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Basic ConsiderationsBasic Considerations
Consist of 4 separate parts
Height of CG at takeoff – H1
Height of CG raised while on the
pole
Height of CG in airborne
Difference between max height and
height of bar
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Height
H2 H4H1 H3
Velocity at release
Body Position at Peak
Movement over bar
Physics Body Position
at takeoff
Kinetic energy at takeoff
Strain energy at takeoff
Work done during ascent
Mechanical energy losses
Kinetic energy at release
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Energy ChangesEnergy Changes
∆Ep = Ek at takeoff + Estrain at takeoff
+ Work done at takeoff
- mechanical energy losses
- Ek at release
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