Field Methodsfor Sprint Profiling

Methods - Advantages - Limitations

Prof. J-B Morin, PhD

@jb_morin

jbmorin.net

April 2020

Conflict of InterestScience and Research Consultant

jb morin

MACROSCOPIC APPROACH: BIG PICTURE FIRST

R. McNeill Alexander(1934-2006)

University of Leeds (UK)

Pietro E. di PramperoUniversità Degli Studi di

Udine (Italy)

The simpler the model, the clearer it is which of its features is essential

to the calculated effect (performance)

Underlying mechanisms not studied first…

but NOT NEGLECTED

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PARSIMONY and SIMPLICITY

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"Entities should not be multiplied without necessity"

"the simplest solution is most likely the right one"

Pr Aaron Coutts, UTS Sydney

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MODELS OF SPRINT « PERFORMANCE »

Credit: ALTIS

Running speed = Step Length x Step Frequencyeg 4 Steps/s x 2.5 m = 10 m/s

Newtonian dynamicsCauses of our movements

Acceleration Max speed

KINETICS - DYNAMICS (Center of mass)

KINEMATICS (Segments)

HOW WE SEE THINGS

Credit: High Performance Traing for Sports, in Press, Human Kinetics

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Ground Reaction Force

Sprint pattern / form

Category: Coaching

2011

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Kugler & Jahnsen 2009JB Morin 2011, 2012-2019G Rabita 2015R Nagahara, 2017 - 2020S Colyer, 2018

PRODUCE TRANSMIT

Sprint acceleration performance

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Methods

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1 second….10 to 12-m

Matt Cross(Univ Savoie & Nice

AUT, Auckland)@MattCrossNZ

Two (im)possibilities

INSTRUMENTED SPRINT TREADMILLSt-Etienne, FranceDoha, Qatar

FORCE PLATESINSEP, Paris, France (7m)Kanoya, Japan (50m+)

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vmax

t

v(t) = vmax.(1-e(-t/t))

Furusawaetal.,1927Henry,1954Volkov&Lapin,1979diPrampero etal.,2015

RunningSpeed(m/s)

Distance(m)Morin Jr.3yrs

Charles Eugster

96yrs

2016: P. SamozinoOK, How can we do with field devices??

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Newtonian dynamicsPosition/Speed -> GRF

v(t) = vmax.(1-e(-t/t)) Furusawaetal.,1927Henry,1954Volkov&Lapin,1979diPrampero etal.,2015

OK, How can we do with field devices??

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A.V. Hill

v(t) = vmax.(1-e(-t/t)) Furusawaetal.,1927Henry,1954Volkov&Lapin,1979diPrampero etal.,2015

OK, How can we do with field devices??

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2016 AND 2019: VALIDATION AGAINST FORCE PLATES

jb morinRyu Nagahara

2016 AND 2019: VALIDATION AGAINST FORCE PLATES

Simple inputs (body mass, running velocity or time)

High reliability

In practice…1 acceleration up to Vmax

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jbmorin

@MySprintApp

2016: P. Jiménez-Reyes

SIMPLER THAN SIMPLE…

Iphone / iPad:

240 frames/s

EJ Marey, 1885, 24 fps

Pedro JIMENEZ-REYESURJC, Madrid

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1. Sprint acceleration with no resistance

Time (s)

Velo

city

(m

/s)

Raw Velocity

Exponential Fitting

2. Computation of Velocity, Force and Power

Time (s)

Velo

city

(m

/s)

and

HZT

Fo

rce

(N/k

g)

Velocity

PowerHZT Force

HZT

Pow

er (W

/kg)

3. F-V and P-V profiles

Velocity (m/s)

HZT

Pow

er (W

/kg)

Velo

city

(m

/s)

F0

V0

Pmax

Vopt

4. Main mechanical outputs: Individualized

Max HZT force F0 and Velocity V0

Pmax and associated Vopt

F-V Profile orientation

Mechanical effectiveness

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Example:1080Sprint data

FORCE-VELOCITY-POWER outputs of Usain Bolt’s World Record

RunningSpeed(m/s)

Distance(m)

FieldMeasurementsIncompetitionconditions

Computing

MaxPowerOutputof30W/kgreachedafterabout1s…

Power=ForcexSpeed…Specific,FieldSprintForce-Velocity-Powerprofile

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5. Individual linear load-Vmax relationship4. Sprints: increasing resistances

Velo

city

(m/s

)

Time (s)

Max VelocityPhase or 5-m split

6. Calculate the load for targeted FV zone

Load at which Vmax = Vopt = 0.5V0

Example: 50%Vdec = 3.6m/s => 1080Sprint Load= 30kg

Specific Spreasheet

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LOAD-Velocity individual profilePROGRAMMING

RESISTED SPRINT WORK?%BM %Vdec

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Sprint Kinematics

Mendiguchia et al. In preparation

60 !Nagahara et al. 2014

Iphone / iPad:

240 frames/s

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2D Basics

Johan Lahti(Univ Nice)

@lahti_johan

High ResistanceAcute changes

Reference Framework

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APPLICATIONS TESTING & TRAINING

« Strong »atLow Velocity « Strong »atHighVelocity

14 sports >500 athletes Leisure to elite levelNo correlation overall, same sub-group outcome for each level and each sport, SAME RESULTS FOR SPRINTING

NOTthereality Thereality

MoremaximalforceMoremaximalvelocity

« Stronger = Faster »

Red: F0-V0 correlationBlue: Individual FV profiles

Jimenez-Reyes et al.Peer J, 2018

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TYPICAL EXAMPLE:Player is « slow »……but has high velocity capabilities !

40-m test : 6.21 vs 6.37 s

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Same 30-m time, very different mechanical profiles…

EXAMPLE: ELITE RUGBY UNION TEAM FOLLOW-UP

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What training input(s) for what component(s)

of the FV spectrum?

Towards Individualized Sprint Training…

Morin et al. 2017 IJSPPCross et al. 2018 IJSPPCross et al. 2019 PLoS OneMorin et al. 2020 JSCRLahti et al. In revisionLahti et al. In preparation

EXPLORING120%BM sleds to 10% OVERSPEED

entire spectrum !

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« Toothpaste Tube Theory »

Don’t do the same betterDo something ELSE

SUMMARY…

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LIMITATIONS

MODEL? METHOD? DEVICE? SUBJECTS? PROTOCOL? ANALYSIS?

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« ACTIONABLE SIMPLIFICATON »

MODEL? METHOD? DEVICE? SUBJECTS? PROTOCOL? ANALYSIS?

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Credit: ALTIS

1. Not all sources of power

35 !« Internal » and intra-step

Is it related to performance?What source of « power » is key?

RADARMODEL? METHOD? DEVICE? SUBJECTS? PROTOCOL? ANALYSIS?

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2. Initial speed data

Credit: Springer, Morin & Samozino 2018

1080 Sprint

CLEAR START

No « pre-GO » movement

Single all-out push

Familiarization?

SPLIT TIMES

Major influence on F and P outputs

MODEL? METHOD? DEVICE? SUBJECTS? PROTOCOL? ANALYSIS?

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3. Familiarization

BEFORE ANY TESTING, TRAINING or RESEARCH protocol…

WHATEVER the LEVEL

∼8 weeks – 2 times per week (2-4 sprints)

Progressive increase in load ➫ 100% BM or 50%Vdec

Progressive increase in distance per sprint ➫ Vmax

Progressive increase in # of loaded sprints

Same approach with assisted sprints

Or….high risk of

meaningful data

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SUMMARY

Acceleration individual FVP and load-V profiles bring novel, key informations

Possible with field devices (very good feasability-validity ratio)

Important methodological « non-negotiables »

BUT BUT

Keep assumptions and limitations in mind

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THANK YOU !