neuromechanics of speed development
TRANSCRIPT
SCIENCE OF SPEED!Mike Young, PhD!
Vancouver Whitecaps FC!Vancouver, BC!
HPC - Athletic Lab!Cary, NC!
!
@mikeyoung #speedscience
•Fundamental physics•General concepts•Sprint math•Secrets of the force
•Neuromechanical considerations•Optimizing mechanics•Basic training guidelines
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F=MA
NEWTON’S 4th LAWFat (or any excess body mass) don’t fly
• Force is a vector quantity!
• Magnitude !
• Direction
EXAMINING FORCE
Drag Increases
Exponentially
INERTIA It turns out Sir Isaac was right
GENERAL CONCEPTS OF
SPRINTING
by Hugo Faasta
BACK SIDE MECHANICS
Refers to the motions of the swing leg that occurs BEHIND the body
FRONT SIDE MECHANICS
Refers to the motions of the swing leg that occurs IN FRONT of the body
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SPRINT PERFORMANCE
• Sprint performance is the outcome of nature and nurture!
• There are reflexive and innate components as well as trainable components
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Loren Seagrave
Dr. Ralph Mann
Sprinting fast is an unnatural activity
You can’t polish a turd.
You can’t polish a turd.But you can roll it in glitter.
Sprint Math
*Maximal Velocity: ~12.8 m/s!
!
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*Ground Contact Time: ~0.08 sec!
*40-45 steps for sub 9.80 100m
*Stride Frequency: ~5 Hz!
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*Stride Velocity: ~300 deg / sec!
*Stride Lengths: 2.25-2.7m
MAXIMAL VELOCITY CHARACTERISTICS
It was Once Thought that Stride Length x Frequency = Speed
Because Athletes had higher stride lengths & frequencies at higher speeds, it was thought
that to improve speed, efforts should be focused on these two variables
BUT....
Correlation!D O E S N OT i m p l y !
Causat ion
now we are more enlightened...
• Stride length and frequency are linked...they are a consequence and not a cause of speed
• Speed of movement of limbs varies little and is not a primary determining factor
STRIDE LENGTH & FREQUENCY
To run faster there is only ONE solution
Apply More Mass Specific Force to
the Ground!
Max V Sprinting 101Small Mass
+ Big Force
+ Right Direction
+ Minimal Time
Run Faster
•Gravity....ugh•We work to overcome gravity•Excess mass hurts performance
•More force = more speed
•Air time is comparable across speeds
•Limb speed....meh
•Vertical force is KING
•Stride length correlates with speed
•Horizontal force is critically important
Insert research on French
•CL more effective at applying force•CL produces higher relative net horizontal force •CL velocity component of F-V is higher•CL has shorter contact times •CL has higher stride frequency
CL =
Chr
istop
he L
eMait
re
KINETIC PARAMETERS
• Ground reaction forces approaching 5x bodyweight!
• Muscle forces in excess of 7x bodyweight
• To increase running speed an athlete must increase force to the ground in the appropriate direction and do so over increasingly shorter periods of time!
• Minimize horizontal braking forces*!
• Increase propulsive forces
FORCE DEVELOPMENT & SPRINTING
Horizontal vs Vertical Propulsive Forces....!
Horizontal vs Vertical Propulsive Forces....!and why you don’t have to pick a side
VERTICAL FORCE MATTERS…
Rela%onships,among,jumping,performances,and,sprint,parameters,during,maximum,speed,phase,in,sprinters,,by,Kale,,Asci,,Bayrak,and,Acikada,,in,Journal,of,Strength,and,Condi%oning,Research,,2009!
• Increased vertical propulsive force produces:!
• Greater displacement!
• Stiffer spring!
• Better maintenance of momentum
VERTICAL PROPULSIVE FORCE
from Strength & Conditioning Research
…BUT SO DOES HORIZONTAL FORCE
THE LEG AS A SWINGING SPRING
• Refers of the ability of the leg to act as like a spring
• Momentum is developed during acceleration
• Body will move at same rate unless acted on by unbalanced forces
• Two external forces will cause deceleration
• Leg stiffness increases vertical impulse, shortens ground contact and increases elastic return
INCREASE LEG STIFFNESS
VS
Vertical Displacement?
The path of COM will follow a sinusoidal curve when viewed in the sagittal plane
COM reaches apex in flight
COM low point during support
Vertical force production is the key component of top-end
speed and that in turn influences the ability to
maintain a slight increase in stride length and stride
frequency
Dan Pfaff
Charlie Francis
To go faster, you need more force. The more force you apply, the
higher you will rise off the ground.
Better sprinters may appear to bounce
In reality, flight times are similar and ground contact times are shorter
• Stride frequency is comprised of two components: !
1. Ground contact time !
2. Flight time!
• The best sprinters spend less time on the ground !
◦ Greater frequency
MORE SPRINT MATH
The benefit of greater force application is two-fold:!• Increased stride length • Increased stride frequency
STRIDE LENGTH &
FREQUENCY
Neuromechanical Considerations
Sprinting is an extremely complex motor task involving repeated rapid ‘switching on and off’
of practically every muscle in the body
Hip extensors arecritically important during
late swing and stance
A,kine%c,analysis,of,the,ground,leg,during,running,,by,Mann,and,Sprague,,Research,Quarterly,for,Exercise,and,Sport,,1980!
Ac%vity,of,monoJ,and,biar%cular,leg,muscles,during,sprint,running,,by,Simonsen,,Thomsen,,and,Klausen,,in,European,Journal,of,Applied,Physiology,,1985!
Amplitude,and,%ming,of,electromyographic,ac%vity,during sprinting by Jonhagen, Ericson, and Eriksson,,Scandinavian,Journal,of,Science,in,Sports,,1996!
Hip extensors arecritically important during
late swing and stance
Knee extensors help keepthe spring stiff during
support
A,kine%c,analysis,of,the,ground,leg,during,running,,by,Mann,and,Sprague,,Research,Quarterly,for,Exercise,and,Sport,,1980!
Ac%vity,of,monoJ,and,biar%cular,leg,muscles,during,sprint,running,,by,Simonsen,,Thomsen,,and,Klausen,,in,European,Journal,of,Applied,Physiology,,1985!
Amplitude,and,%ming,of,electromyographic,ac%vity,during sprinting by Jonhagen, Ericson, and Eriksson,,Scandinavian,Journal,of,Science,in,Sports,,1996!
Allow the body to take advantage of its own performance enhancers
Crossed-Extensor Reflexes
Stretch Shortening CyclesReciprocal Inhibition
and facilitate V
Optimizing
Mechanics
•Better sprinters are front-side
dominant
•Better sprinters have shorter
contact times
•Full extension neither needed
nor beneficial
•Ideal touchdown characterized
by swing knee even with
support knee
POS TU URE
The first most important
aspect of speed is posture.
Tom Tellez
Posture is like the mast and rudder for the limbs
Posture
Trunk Erect
Head Level
Hips Tall
Posture
• Movements of the limbs originate from the core of the body!
• Proper stabilization and alignment of the core ensures appropriate movements of the limbs
POSTURE
• Postural Stabilization!
• Postural Alignment!
• Relaxation!
• Freedom of movement!
• Elastic energy production
POSTURE
• The pelvis should rotate in all three planes
PELVIC MOTION
Postural Test!
PELVIC TILT
Posterior Tilt = less hamstring tension, more QFM tension!
Anterior Tilt = more hamstring tension, less QFM tension
EFFECT OF POSTURE ON SPEED
EFFECTIVE GROUND CONTACT POSITION
• Decreases horizontal velocity!
• Caused by excessive step length and positive foot and leg speed at ground contact
MINIMIZE BRAKING FORCES
Vertical Stack
High Knee Recovery
Neutral Ankle
Congruent ContralateralJoint Angles
Fix posture Emphasize vertical pushes
“Push up” High hips
“Run tall” Step over and down
Max Velocity Technical Points
Basic Training Guidelines for Developing Speed
Building a Bigger Engine
THE REAL REASON WE TRAIN
Almost every physical quality relevant to speed & power falls under the umbrella of (neuromuscular)
coordination
!
By considering physical qualities as outcomes of inter & intramuscular coordination we simplify the training method and place stimuli on a continuum
rather than in different bubbles
To Sprint Faster.... Sprint!
Maximum Velocity Sprinting•Means:
•Flying Sprints
•Variable Speed Sprints
•Short Speed Endurance
•Length (in MaxV): 10-40m / rep
•Rest: 20-60 sec / 10m
•Volume: 200-300m
DOWNHILL RUNNINGminimal grade. overspeed. supra-maximal eccentric.
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RESISTANCE TRAINING
Strength ≠ Speed
“...there is sufficient evidence for strength training programs to
continue to be an integral part of athletic preparation.”
“Do I really need to lift?”
OLYMPIC LIFTS1-4 reps / set. 5-10 sets.
Exercise Absolute Power (Watts)100kg Male 75kg Female
Bench Press 300
Back Squat 1100
Deadlift 1100
Snatch 3000 1750
Snatch 2nd Pull 5500 2900
Clean 2950 1750
Clean 2nd Pull 5500 2650
Jerk 5400 2600
POWER DEVELOPMENT
*Total pull: Lift-off until maximal vertical velocity
**2nd pull: Transition until maximal vertical barbell velocity
Exercise Absolute Power (Watts)100kg Male 75kg Female
Bench Press 300
Back Squat 1100
Deadlift 1100
Snatch 3000 1750
Snatch 2nd Pull 5500 2900
Clean 2950 1750
Clean 2nd Pull 5500 2650
Jerk 5400 2600
POWER DEVELOPMENT
*Total pull: Lift-off until maximal vertical velocity
**2nd pull: Transition until maximal vertical barbell velocity
Even if use of Olympic lifts are inappropriate due to lack of equipment, low teaching expertise, or athlete inexperience; the basic principals should still be incorporated (externally
loaded, multi-joint, lower body explosive movement)
SQUATSall variants. full depth. 2-6 reps / set. 4-7 sets.
I like STRONG butts and I can not lie....
TRAIN THE CHAIN (THE POSTERIOR CHAIN)
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ECCENTRIC OVERLOAD110-120% MAXIMAL LOAD. NOT FOR NOVICES.
COMPLEXESwork downstream on F-V curve. rest between sets. low volumes
PLYOS
DEPTH DROPSlow drops. minimize amortization. low volumes.
DEPTH JUMPSextreme heights unnecessary. low volumes.
VERTICAL EMPHASIS PLYOSemphasize vertical displacement of the COM not the feet
STIFFNESS JUMPSminimal amortization. short contact.
MECHANICS & PHYSICAL CAPACITY ARE INTIMATELY INTERTWINED
SPRINTING FASTER IS ALL ABOUT PUTTING AS MUCH FORCE IN TO THE GROUND AT AS LITTLE BODY MASS AS POSSIBLE
OPTIMIZING MECHANICS ENSURES MAXIMAL GENERATION OF FORCE IN THE DESIRED DIRECTION
POSTURE IS THE CORNERSTONE FOR OPTIMAL MOVEMENT
HIP EXTENSORS PLAY A CRITICAL ROLE IN SPRINT SPEED
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