Transcript Biomechanical Commonalities of the Horizontal Jumps

LA84 Coaching Education
Advanced Clinic
Biomechanical
Commonalities of the
Horizontal Jumps
Cameron T. Gary
Mater Dei Catholic H.S. – Chula Vista, CA
USATF Level 2 - Jumps
Basic Jumping
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How do we jump?
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“Triple extension” of hip,
knee and ankle joints
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Fast & Coordinated
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Until foot release
All three must happen in
order to “jump”
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“Summation of Forces”
Non-extension of any one
joint makes the jump
inefficient
VERY basic movement
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Not “functional”, per se
Concentric Jumping
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Main Characteristics
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Pushing only
Strength-oriented
Overcome inertia - move from a stationary position
Body at rest tends to stay at rest…
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Sprint starts
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Beginning of approach run
We train this attribute through:
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Bodyweight Exercises (e.g., Lunges)
Conventional weight lifting
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squats, power cleans, snatches, dead lifts, etc.
Jumping up onto a surface
Running up stairs
Eccentric & Isometric Strength
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Eccentric Contraction
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Muscle lengthens under tension
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Stronger than Concentric
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One can lower more weight than they can lift
Isometric (“isolate” + “measure”)
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Such as lowering the weight on a Bench Press
Muscle contraction w/o movement of joint
Very brief but very important
These attributes are trained by:
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Lowering and/or holding weight
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“Farmer’s” Carry, etc.
Running/jumping then stopping (“Catching”)
Jumping down (“Sticking”)
Running down stairs
Pre-Recruitment
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Increase tension before concentric contraction
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Eccentric and Isometric
The resulting concentric contraction is
stronger
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Can utilize some of the muscle’s elastic properties
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Analogous to stretching a rubber band
More Functional
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Dorsi-Flexion of foot before planting
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Cocking the arm for a punch
Basic Applied Skills
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Full foot – the most basic skill a jumper must learn
 The same for the Long Jump and Triple Jump
 But not a “dead” foot
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Dorsi-flexion enables pre-recruitment of muscles
Emphasize the middle of the foot striking the ground
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Activates the larger muscles of the upper leg and hip
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NOT heel first
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NOT toe first
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Deliver a Blow to the Runway/Board
“Pawing” – It may encourage dropping the toe (BE CAREFUL!)
Useful verbal cues:
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Squish a bug
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Break a board
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Push a skateboard
Counter-Movement Jumping
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Rapid weight drop
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Temporarily “increase” weight
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Descent is briefly stopped
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Quickly reversed
Isometric strength must be great
Arms increase force into the ground
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W/O increasing mass
Applied downward then upward
Body “lightens” as a result
Energy is “returned” to the body
Increased force into the ground = increased energy return to
the body
Demo Basic CM Jump
Plyometric “Springy” Effect
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Stretch-Shortening Cycle
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RAPID Absorption > Stabilizing > Explosion
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The FASTER the better
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Focus on dynamic power (strength vs. time)
Develop functional tension (within reason)
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Analogy: Bouncing rubber ball
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The harder the ball, the higher the bounce
Maximum speed sprinting
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Shallow knee angles – Fast ground contact
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Multiple “jumps” down the track
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One cannot “push” fast enough
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Sinusoidal movement of pelvic girdle
“Horizontal” jumping really isn’t horizontal
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Transitional vertical impulse – just like sprinting
“Loading” the Plyometric Spring
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Foot strikes are active – “negative foot speed”
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NEVER foot strike toe-down – common issues:
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“Double hit” and/or foot “stammer”
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Encourages reaching far ahead of the COM
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Premature hinged-moment
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This is what you do when you want to stop
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Activates the smaller muscles – think “Proximal-Distal”
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Be VERY careful with the so-called “B-Skip”!
Foot Dorsi-Flexion “loads” the Achilles tendon
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Prepares calf/hamstring muscles for a stronger response
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Be careful of how you drill
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Anything worth doing is worth doing right
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No point in practicing things that weaken athletic skills
You have to get down to get up
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Dwight Phillips LJ video
Hinged-Moment Analogy
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If you imagine a pogo stick w/ wheels, you understand the hinged-moment
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This is what propels a pole-vaulter over the bar
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However, there is stored energy in the flexible pole – same for muscles
Is what allows us to jump vertically while moving horizontally
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The reason for the penultimate/pre-recruitment transition
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Foot contact “checks” horizontal velocity - imparting forward rotation
Effect of Forward Rotation
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The body rotates around the COM
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Parabolic Path is Established at Takeoff
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Can maximize or mess it up…but not extend it
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Minimize excessive forward rotation
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Utilize some forward rotation
Posture
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Upright at take-off (neutral spine)
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Upright during flight
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NOT upright at landing
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Feet land relative to body rotation around COM
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Abdominal strength has NO effect on this
Horizontal Jump Objective
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Project Center of Mass (COM)
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As far as one can, from the board, into the pit
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Path is determined at take-off
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However – there is a constant battle vs. forward rotation
Optimal take-off angles – why?
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18 – 22 degrees – horizontal velocity is main contributor to distance
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Project COM out, not up
COM starts from above the ground
Action-Reaction
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Newton’s Laws…
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Arms relative to Torso
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Every action causes an equal and opposite reaction
Problem manifested – result of what precedes it
Set the pace/tempo
Rear Arm Sweep Example
Horizontal
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Vertical
Legs relative to whole body (flight mechanics)
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Same affect as the arms, but bigger
Hitch-Kick Effect
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Legs push hips forward, arms push torso backward
Triple Jump Demo (Idowu)
Center of Mass
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Mass is NOT weight
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Mass is a function of matter
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Weight is a function of the magnetic
pull of mass toward the earth’s core
Earth vs. Moon
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Body Positions re: COM
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Standing
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Bending
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Front
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Side
Arms play a role – DON’T forget
them!
Relevant to the flight
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Especially landing positions
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Arms forward v. backward
Wall Test
Momentum (Mass x Velocity) –
VERY Important
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Start of approach - main attribute: strength/power
Top speed/end of run - main attribute: speed/reaction
Only necessary for horizontal jumpers to maintain high
running velocities for 10 – 15 meters
 Long interval running is not necessary (may be counterproductive) for
jumpers!
 Use short rest intervals to develop anaerobic power
 However, jumpers must be able to run VERY fast!
 But under control
 Jumpers must convert horizontal to vertical QUICKLY
 Skipping a stone on water – TJ
 Delivering a blow to the board – LJ
Believe it or not…
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It is possible to run even faster
than sprinters at the end of the
approach
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Almost ALL jump distance is
determined at take-off
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The last few strides of the
approach determine take-off
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In-Air movements only obtain
optimal landing positions
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Majority of training should focus on
how to transfer the run into the jump
Can jumpers really run faster than sprinters
in the approach? Edwards v. Conley
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(1993 and 1995 World Championships)
“Biomechanical Team’s Information Bulletins”
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Conley is the faster sprinter, but as one can see – it is
the speed over the last five meters that tells the tale
 Summary
& Questions
Cameron T. Gary
USATF Level 2 - Jumps
www.ctgdevelopment.net
619-895-4699
[email protected]