Biomechanics in javelin throwing - Hauptseite

Biomechanics in javelin throwing

with special reference to feedback for coaching

Jukka Viitasalo

Research Institute for Olympic SportsJyväskylä, Finland

KIHU

Contents

1. Biomechanical background in javelin throwing

2 C ti b t h d2. Cooperation between research andjavelin throwing in Finland

Run-up speed - radar

Throwing technique - video shooting and motion analysis

Aerodynamics of the javelin - pneumatic javelin gun

Release parameters - photocell gate


Bartlett and Best The biomechanics of javelin throwing : a reviewJ. Sp. Sci., 1988

Hay Javelin throwin The Biomechanics of Sports Techniques, 1978

Hubbard The throwing events in track and fieldin The Biomechanics of Sport II, 1987

Morris and Bartlett Biomechanical factors critical for performancein the men’s javelin throwSports Med 1996Sports Med., 1996

Terauds Biomechanics of the javelin throwA book, 1985

Factors affecting the distance thrown

Release speed


p

Release angle

Release angle of attack

Release angle of yawg y

Release pitching moment

Aerodynamic factors Hay, 1993Morris and Bartlett, 1996


Run-up

Crossover strides

Delivery stride

Final foot strike

AAJavelin velocityvector (RS)

RA

AA = Angle of attackRA = Release angleRS = Release speed

Biomechanical service for theFinnish elite javelin throwers

2. Cooperation between research and javelin throwing in Finland

Selection of methods and variables :

• Importance of the variable on throwing performance and javelin aerodynamics

Finnish elite javelin throwers

performance and javelin aerodynamics

• Demands of coaches and throwers

• Possibility to measure the variables


Variables selected and measured (throwers):

- run-up speed

- biomechanical parameters of the delivery stridebiomechanical parameters of the delivery stride

- biomechanical variables of the thrower during thefinal foot strike (between touch down of the left footand release of the javelin)

- release speed, release angle, angle of attack, distance thrown

Variables selected and measured (javelin aerodynamics):(j y )

- release speed, angle and flight distance

- different javelin types, wind conditions, effects of rotation

- effects of the javelin’s center of mass on flight distanceand landing position

Run-up speed - radar

7

8

JAVELIN THROWING: Run-up speedSpeed (m/s)

1

2

3

4

5

6

RÄTY S

KINNUNEN K

0

1

051015202530Distance (m)



- run-up speed







- effects of the javelin’s center of mass on flight distnaceand landing position

Throwing technique - video shooting and motion analysis

Calibration

Velocity(m/s)

Height of C.M.(cm)

Velocity and displacement of C.M. / Heli Rantanen -96Touch down Take-off

5 .0 m /s

2 .8 m /s

0

1

2

3

4

5

6

-0 ,0 6 -0 ,0 4 -0 ,0 2 0 0 ,0 2 0 ,0 4 0 ,0 6 0 ,0 8 0 ,1 0 ,1 2 0 ,1 4 0 ,1 6 0 ,1 8

8 4

8 6

8 8

9 0

9 2

9 4

9 6

9 8

1 0 0

Ve lo c ity o f C .M .

L o c a tio n o f C .M .

(cm)

Time (s)

Heittokäden liikerata

ReleaseHeli Rantanen - 96

y = 1.77 m

Release

kowx = 0.10 m

30

Linear velocities / Heli Rantanen -96

Touch down Take-offVelocity

(m/s)

25.8 m/s

19.0 m/s

14.4 m/s

8 3 m/s10

15

20

25

Palm

Wrist

0.14 s

0.14 s0.09 s

E lb8.3 m/s

0

5

-0.06 -0.04 -0.02 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18

Shoulder

R. h ip

0.09 s

E lbow

Time (s)

Angle(°)

Angular displacements / Heli Rantanen -96

159

146

171

121

141

132122

120

140

160

180

200

Knee

Hip

(°) Touch down Take-off

77

60

80

100

-0.06 -0.04 -0.02 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18

Elbow

Time (s)

5.0 m /s

4

5

6

94

96

98

100

Velocity of C.M.

Velocity(m/s)

Height of C.M.(cm)

Velocity and displacement of C.M. / Heli Rantanen -96

Touch down Take-off

2 .8 m /s

0

1

2

3

-0.06 -0.04 -0.02 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.1884

86

88

90

92

94

Location of C.M.

Time (s)

113 °

142 °

100

120

140

160

Shoulder

Angle(°)

Angular displacements / Heli Rantanen -96

Touch down Take-off

78 °

52 °

20

40

60

80

100

-0.06 -0.04 -0.02 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18

0.09 s

Pelvis

Time (s)



- run-up speed








AAJavelin velocityvector (RS)


RA

AA = Angle of attackRA = Release angleRS = Release speed



Release parameters- photocell gate


Detection phaseRelease parameters - photocell gate

- two infrared walls ; 2.0 and 2.5 m height300 photocells

Location phase

- 300 photocells

- detection phase :- 50 kHz, fan shape- resolution 1-3 mm

- location phase- 1 kHz- 15 mm resolution

Release speed vs. release angle

• 11 maximal throws• male javelin thrower

Viitasalo and Korjus, 1988

• male javelin thrower• release angles between 18 and 32 deg

Optimum for neuromuscular functioning

optimum for physics of throwing motion

RELEASE PARAMETERS AND RELEASE PARAMETERS AND THROW DISTANCETHROW DISTANCETHROW DISTANCE THROW DISTANCE

IN ELITE JAVELIN THROWINGIN ELITE JAVELIN THROWING

K. K. NorvapaloNorvapalo , H. Mononen and J. Viitasalo , H. Mononen and J. Viitasalo

KIHUKIHU-- Research Institute for Olympic Sports , Research Institute for Olympic Sports , JyväskyläJyväskylä, Finland, Finland

PURPOSE

to investigate the relationship between to investigate the relationship between

the release parameters and throw distancethe release parameters and throw distance

among elite javelin throwersamong elite javelin throwersg jg j

METHODS / MEASUREMENTS

• 159 throws of 26 males

• competitions in Finland

during 1995-1998

98 throws of 15 females

• throw distance range for

women 55.00 - 66.00 m

men 75.00- 87.82 m

METHODS / PARAMETERS

• Release speed (m * s-1)• Release speed, (m * s 1)

• Release angle, (°)

• Angle of attack, (°)

• Official throw distance (m)

RESULTS

RELEASE SPEED - group

32.50

RELEASE SPEED (m* s -1)

20.00

22.50

25.00

27.50

30.00

MEN

R2= 0.50p < 0.001

n= 159

R2 0 51

WOMEN

15.00

17.50

50.00 55.00 60.00 65.00 70.00 75.00 80.00 85.00 90.00

THROW DISTANCE (m)

R2= 0.51p < 0.001

n= 98

RELEASE SPEED - individual

32.50

RELEASE SPEED (m* s -1)

RESULTS

20.00

22.50

25.00

27.50

30.00

2

FEMALE 1

R2= 0.43p < 0.01

n= 23

MALE 1

15.00

17.50

50.00 55.00 60.00 65.00 70.00 75.00 80.00 85.00 90.00

THROW DISTANCE (m)

R2= 0.52p < 0.001

n= 19

RELEASE ANGLE - group

40.00

42.50

RELEASE ANGLE (°)

RESULTS

27.50

30.00

32.50

35.00

37.50

40.00

R2= 0.01

MEN

WOMEN

20.00

22.50

25.00

50.00 55.00 60.00 65.00 70.00 75.00 80.00 85.00 90.00

THROW DISTANCE (m)

nsn= 159R2= 0.02

nsn= 98

RELEASE ANGLE - individual

42.50

RELEASE ANGLE (°)

RESULTS

27.50

30.00

32.50

35.00

37.50

40.00

FEMALE 1 MALE 1

20.00

22.50

25.00

50.00 55.00 60.00 65.00 70.00 75.00 80.00 85.00 90.00

THROW DISTANCE (m)

R2= 0.31p< 0.05n= 19

R2= 0.35p< 0.05n= 16

Number of Men Women

Competitons 6 7

Trowers 63 40

Throws 184 133

Men

Result = 3.52*v + 0.39*ra - 0.14*aa – 29.45 R2 = 0.66

Women

Throws 184 133

Result = 3.82*v + 0.08*ra - 0.11*aa – 31.23 R2 = 0.80

v = release speed (m/s)ra = release angle (deg.)aa = angle of attack (deg.)

Release ReleaseRelease speed and speed, angle and

d l l f tt k

RESULTS

THROW DISTANCE vs RELEASE PARAMETERS - MEN(Regression analyses, R2 )

speed angle angle of attack

Ath 1 (n=11) 0.29 0.50 0.73

Ath 2 (n=13) 0.64 0.76 0.80

Ath 3 (n=15) 0.80 0.80 0.80

Ath 4 (n=16) 0.82 0.82 0.88

Ath 5 (n=18) 0.55 0.55 0.59

Ath 6 (n=23) 0.43 0.57 0.66

• among elite javelin throwers the release speed was the best parameter to predict the throw distanceboth at group and individual level

CONCLUSIONS

both at group and individual level

• the release angle had significant relationshipwith throw distance only at individual level

• the angle of attack did not alone significantlyaffect on the throw distance

• the explanatory power of various release parameters on the official throw distance differed in individual and group levels



- run-up speed





- release speed, angle, rotation around the long axixs and flight distance




Release speed 29 m/s, no wind93

94

Flight distance (m)


88

89

90

91

92

Champion a

Tailwind 90

Champion b

85

86

87

30 31 32 33 34 35 36 37 38 39Release angle (º)

80,00

Flight distance(m)

B

Javelin : Diana 80

Release angle 34 °


60,00

65,00

70,00

75,00 A

-------------------------------------------Javelin

Change of CM Landing to the tip

-------------------------------------------A 0 mm 38 %

B

50,00

55,00

21,00 23,00 25,00 27,00

Release speed (m/s)

B 5 mm 67 %C 15 mm 88 %D 31 mm 95 %-------------------------------------------C

D

There is only one optimal technique for anyparticular thrower but it varies considerablybetween individuals

Some conclusions

Best et al., 1993

What is optimal in respect of throwing physicsis not necessarily optimal in respect of theneuromuscular functioning

The aerodynamic characteristics differ betweenjavelin models/manufacturers as well as betweenindividual javelins

Thank YouJukka Viitasalo

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Biomechanics in javelin throwing - Hauptseite