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Wha
t You
Nee
d to
Kno
w A
bout
th
e Sp
rint S
tart
Ral
ph M
ann,
Ph.
DR
alph
Man
n, P
h.D
.. R
alph
Man
n, P
h.D
Ral
ph M
ann,
Ph.
D..
Bio
mec
hani
csB
iom
echa
nics
In
Mem
oriu
m
Jam
es H
ay
C. H
arm
on B
row
n B
ert L
yle
The
Goa
l G
et to
the
finis
h lin
e fir
st!
Und
erst
andi
ng T
he S
prin
t Pe
rfor
man
ce
Und
erst
andi
ng T
he S
prin
t Pe
rfor
man
ce
Gen
erat
e as
Muc
h Pr
oduc
tive
Forc
e as
G
ener
ate
as M
uch
Prod
uctiv
e Fo
rce
as
Poss
ible
in a
s Litt
le T
ime
as P
ossi
ble
Poss
ible
in a
s Litt
le T
ime
as P
ossi
ble
Gen
erat
e as
Muc
h Pr
oduc
tive
Forc
e as
G
ener
ate
as M
uch
Prod
uctiv
e Fo
rce
as
Poss
ible
in a
s Litt
le T
ime
as P
ossi
ble
Poss
ible
in a
s Litt
le T
ime
as P
ossi
ble
Gra
nd U
nific
atio
n Sp
rint T
heor
y
1.1.Fo
rce
Can
Onl
y B
e G
ener
ated
on
the
Gro
und
Forc
e C
an O
nly
Be
Gen
erat
ed o
n th
e G
roun
d 2.2.
Bod
y C
ente
r (C
OG
) Pos
ition
is C
ritic
al
Bod
y C
ente
r (C
OG
) Pos
ition
is C
ritic
al
Gen
erat
e as
Muc
h G
ener
ate
as M
uch
Prod
uctiv
ePr
oduc
tive
Forc
e as
Fo
rce
as
Poss
ible
in a
s Litt
le T
ime
as P
ossi
ble
Poss
ible
in a
s Litt
le T
ime
as P
ossi
ble
Gen
erat
e as
Muc
h G
ener
ate
as M
uch
Prod
uctiv
ePr
oduc
tive
Forc
e as
Fo
rce
as
Poss
ible
in a
s Litt
le T
ime
as P
ossi
ble
Poss
ible
in a
s Litt
le T
ime
as P
ossi
ble
Gra
nd U
nific
atio
n Sp
rint T
heor
y
The
Vel
ocity
Pro
file
in th
e 10
0m
Sprin
t Per
form
ance
1
0 1 2 3 4 5 6 7 8 9 10
11
12 0
10
20
30
40
50
60
70
80
90
100
Dis
tanc
e (m
)
Velocity (m/sec)
Vm
ax
Hor
izon
tal V
eloc
ity P
rofil
e
THE
PHA
SES
OF
SPR
INTI
NG
Sprin
ting:
Hor
izon
tal V
eloc
ity
024681012
Velocity (meters/sec)
Hor
izon
tal V
eloc
ity
Sprin
ting:
Hor
izon
tal V
eloc
ity
024681012
Velocity (meters/sec)
Hor
izon
tal V
eloc
ity
St
art
Sprin
ting:
Hor
izon
tal V
eloc
ity
024681012
Velocity (meters/sec)
Hor
izon
tal V
eloc
ity
80
%
Star
t
Sprin
ting:
Hor
izon
tal V
eloc
ity
024681012
Velocity (meters/sec)
Hor
izon
tal V
eloc
ity
80
%
St
art
Tran
sitio
n
2
Sprin
ting:
Hor
izon
tal V
eloc
ity
024681012
Velocity (meters/sec)
Hor
izon
tal V
eloc
ity
80
%
St
art
Tran
sitio
n M
ax V
eloc
ity
The
Phas
es o
f Spr
intin
g �
Rea
ctio
n Ti
me
(gun
to fi
rst m
ovem
ent*
) �
Acc
eler
atio
n
a.
Sta
rt
1. T
wo
Leg
Driv
e
2. O
ne L
eg D
rive
3.
Firs
t Ste
p
4. S
econ
d St
ep
b. T
rans
ition
�
Max
imum
Vel
ocity
a.
Atta
in
b. M
aint
ain
The
Phas
es o
f Spr
intin
g �
Rea
ctio
n Ti
me
(gun
to fi
rst m
ovem
ent*
) �
Acc
eler
atio
n
a.
Sta
rt
1.
Tw
o Le
g D
rive
2.
One
Leg
Driv
e
3. F
irst S
tep
4.
Sec
ond
Step
b.
Tra
nsiti
on
�M
axim
um V
eloc
ity
a. A
ttain
b.
Mai
ntai
n
The
Phas
es o
f Spr
intin
g �
Rea
ctio
n Ti
me
(gun
to fi
rst m
ovem
ent*
) �
Acc
eler
atio
n
a.
Sta
rt
1.
Tw
o Le
g D
rive
2.
One
Leg
Driv
e
3. F
irst S
tep
4.
Sec
ond
Step
b.
Tra
nsiti
on
�M
axim
um V
eloc
ity
a. A
ttain
b.
Mai
ntai
n
Theo
ry D
evel
opm
ent
�R
esea
rch
Sinc
e 19
82 (U
SATF
Fun
ded)
�
Top
Sprin
ters
in C
ompe
titio
n �
Bio
mec
hani
cal/S
tatis
tical
Ana
lysi
s �
Scie
ntifi
c M
etho
d Em
ploy
ed
–O
pini
on
–H
ypot
hesi
s –
Theo
ry
�O
n-Tr
ack
App
licat
ion
Focu
s �
Sprin
ting
�10
0 M
eter
s �
Mal
e A
thle
tes
�St
art
�U
nder
stan
ding
the
Even
t
3
The
Star
t
?? S
econ
ds??
Sec
onds
Diff
eren
ce B
etw
een
9.5
& 1
0.5
Diff
eren
ce B
etw
een
9.5
& 1
0.5
Diff
eren
ce B
etw
een
9.5
& 1
0.5
Diff
eren
ce B
etw
een
9.5
& 1
0.5
Intro
duct
ory
Que
stio
n: T
he S
tart
Set P
ositi
on
Firs
t Mov
emen
t
3 M
eter
Mar
k
Hea
d H
its L
ine
Slow
est:
1.02
sec
Fa
stes
t: 0
.72
sec
0.30
Sec
onds
to th
e 3
Met
er
0.30
Sec
onds
to th
e 3
Met
er
Mar
k (~
3 St
eps)
Mar
k (~
3 St
eps)
Diff
eren
ce B
etw
een
9.5
& 1
0.5
Diff
eren
ce B
etw
een
9.5
& 1
0.5
Diff
eren
ce B
etw
een
9.5
& 1
0.5
Diff
eren
ce B
etw
een
9.5
& 1
0.5
Intro
duct
ory
Que
stio
n: T
he S
tart
Hor
izon
tal V
eloc
ity P
rofil
e
0 1 2 3 4 5 6 7 8 9 10
11
12 0
20
40
60
80
100
Vm
ax
V2n
d St
ep
4
Hor
izon
tal V
eloc
ity P
rofil
e
0 1 2 3 4 5 6 7 8 9 10
11
12 0
20
40
60
80
100
Vm
ax
V2n
d St
ep
Tim
e Lo
st ~
0.7
sec
0.30
Sec
onds
to th
e 3
Met
er
0.30
Sec
onds
to th
e 3
Met
er
Mar
k (~
3 St
eps)
+ 0
.70
Seco
nds
Mar
k (~
3 St
eps)
+ 0
.70
Seco
nds
to th
e 60
Met
er M
ark
to th
e 60
Met
er M
ark
Diff
eren
ce B
etw
een
9.5
& 1
0.5
Diff
eren
ce B
etw
een
9.5
& 1
0.5
Diff
eren
ce B
etw
een
9.5
& 1
0.5
Diff
eren
ce B
etw
een
9.5
& 1
0.5
Intro
duct
ory
Que
stio
n: T
he S
tart
0.30
Sec
onds
to th
e 3
Met
er
0.30
Sec
onds
to th
e 3
Met
er
Mar
k (~
3 St
eps)
Mar
k (~
3 St
eps)
Diff
eren
ce B
etw
een
9.5
& 1
0.0
Diff
eren
ce B
etw
een
9.5
& 1
0.0
Diff
eren
ce B
etw
een
9.5
& 1
0.0
Diff
eren
ce B
etw
een
9.5
& 1
0.0
Intro
duct
ory
Que
stio
n: T
he S
tart
100
Met
ers M
en: S
tart
Mod
el-A
100
Met
ers M
en: S
tart
Mod
el-B
Set P
ositi
on
5
Two
Leg
Driv
e
Sing
le L
eg D
rive
Step
One
Step
Tw
o
A g
ener
al k
ey (1
) to
over
all s
prin
t sta
rt pe
rfor
man
ce is
to m
axim
ize
the
amou
nt o
f ava
ilabl
e fo
rce
prod
uctio
n.
Sprin
t Stre
ngth
Em
phas
is
Sprin
t Stre
ngth
Em
phas
is
Sta
rt Fo
rces
6
Hor
izon
tal V
eloc
ity
Expe
cted
Hor
izon
tal F
orce
H
oriz
onta
l Blo
ck F
orce
s
0
200
400
600
800
1000
1200
0 0.
05
0.1
0.15
0.
2 0.
25
0.3
0.35
Horizontal Force (Newtons)
Tim
e (S
econ
ds)
Fron
t Leg
B
ack
Leg
200
Lbs
100
Lbs
0 L
bs
Hor
izon
tal B
lock
For
ces
0
200
400
600
800
1000
1200
0 0.
05
0.1
0.15
0.
2 0.
25
0.3
0.35
Horizontal Force (Newtons)
Tim
e (S
econ
ds)
Fron
t Leg
B
ack
Leg
Tota
l
200
Lbs
100
Lbs
0 L
bs
Ver
tical
Vel
ocity
Ex
pect
ed V
ertic
al F
orce
Min
imal
7
0
200
400
600
800
1000
1200
0 0.
1 0.
2 0.
3
Vertical Force (Newtons)
Tim
e (S
econ
ds)
Fron
t Leg
B
ack
Leg
200
Lbs
100
Lbs
0 L
bs
Ver
tical
Blo
ck F
orce
s
Star
t Fo
r the
eac
h st
ep, t
he V
ertic
al V
eloc
ity C
hang
e (�
Vv)
is:
�Vv �
.94
m/s
ec
Verti
cal F
orce
= 7
7.5
kg *
�V
v /.1
50 se
c
Verti
cal F
orce
= 4
85 N
(110
lbs)
Verti
cal B
lock
For
ces
0
200
400
600
800
1000
1200
0 0.
1 0.
2 0.
3
Vertical Force (Newtons)
Tim
e (S
econ
ds)
Fron
t Leg
B
ack
Leg
Bot
h
200
Lbs
100
Lbs
0 L
bs
Ave
rage
Ver
tical
Blo
ck F
orce
s
The
Gra
vity
Pro
blem
St
art
The
verti
cal e
ffort
is st
ress
ed fu
rther
due
to
the
Gra
vity
Han
dica
p:
Rev
ised
Ver
tical
For
ce =
485
N +
750
N
Verti
cal F
orce
= 1
235
N (2
77 lb
s)
Verti
cal B
lock
For
ces
0
200
400
600
800
1000
1200
0 0.
1 0.
2 0.
3
Vertical Force (Newtons) Ti
me
(Sec
onds
)
Fron
t Leg
B
ack
Leg
Bot
h
200
Lbs
100
Lbs
0 L
bs
200
Lbs
Wei
ght
Ave
rage
Ver
tical
Blo
ck F
orce
s
8
Ph
ase
L
ater
al
Hor
izon
al
Verti
cal
Tot
al
Star
t
0 lb
s
205
lbs
277
lbs
35
0 lb
s Tr
ansi
tion
0 lb
s M
ax V
eloc
ity
0
lbs
5
0 lb
s 3
67 lb
s
370
lbs
Sprin
t For
ces
The
Rea
lity
The
Stre
ngth
/Mec
hani
cs P
robl
em
The
Stre
ngth
/Mec
hani
cs P
robl
em
A g
ener
al k
ey (2
) to
Star
t per
form
ance
im
prov
emen
t is t
o m
axim
ize
strid
e ra
te b
y m
inim
izin
g bo
th g
roun
d co
ntac
t tim
e an
d ai
r tim
e.
Star
t Tur
nove
r Em
phas
is
Star
t Tur
nove
r Em
phas
is
Met
hods
To
Incr
ease
Stri
de L
engt
h
�Ju
mp
high
er (i
ncre
ase
verti
cal v
eloc
ity a
nd a
ir tim
e)
�Ex
tend
farth
er a
t Tak
eoff
(inc
reas
e gr
ound
tim
e)
�R
each
farth
er a
t Tou
chdo
wn
(incr
ease
gro
und
time)
�
Run
fast
er (i
ncre
ase
horiz
onta
l vel
ocity
)
Strid
e R
ate
vs. S
tride
Len
gth
9
Met
hods
To
Incr
ease
Stri
de R
ate
�
Jum
p lo
wer
(dec
reas
e ve
rtica
l vel
ocity
and
air
time)
�
Exte
nd le
ss a
t Tak
eoff
(dec
reas
e gr
ound
tim
e)
�R
each
less
at T
ouch
dow
n (d
ecre
ase
grou
nd ti
me)
�
Pull
grou
nd le
g th
roug
h fa
ster
(de
crea
se g
roun
d tim
e)
Strid
e R
ate
vs. S
tride
Len
gth
Met
hods
To
Incr
ease
Stri
de R
ate
�
Jum
p lo
wer
(dec
reas
e ve
rtica
l vel
ocity
and
air
time)
�
Exte
nd le
ss a
t Tak
eoff
(dec
reas
e gr
ound
tim
e)
�R
each
less
at T
ouch
dow
n (d
ecre
ase
grou
nd ti
me)
�
Pull
grou
nd le
g th
roug
h fa
ster
(de
crea
se g
roun
d tim
e)
Met
hods
To
Incr
ease
Stri
de L
engt
h
�Ju
mp
high
er (i
ncre
ase
verti
cal v
eloc
ity a
nd a
ir tim
e)
�Ex
tend
farth
er a
t Tak
eoff
(incr
ease
gro
und
time)
�
Rea
ch fa
rther
at T
ouch
dow
n (in
crea
se g
roun
d tim
e)
�St
art f
aste
r (in
crea
se h
oriz
onta
l vel
ocity
)
Strid
e R
ate
vs. S
tride
Len
gth
Met
hods
To
Incr
ease
Stri
de R
ate
�
Jum
p lo
wer
(dec
reas
e ve
rtica
l vel
ocity
and
air
time)
�
Exte
nd le
ss a
t Tak
eoff
(dec
reas
e gr
ound
tim
e)
�R
each
less
at T
ouch
dow
n (d
ecre
ase
grou
nd ti
me)
�
Pull
grou
nd le
g th
roug
h fa
ster
(de
crea
se g
roun
d tim
e)
Met
hods
To
Incr
ease
Stri
de L
engt
h
�Ju
mp
high
er (i
ncre
ase
verti
cal v
eloc
ity a
nd a
ir tim
e)
�Ex
tend
farth
er a
t Tak
eoff
(incr
ease
gro
und
time)
�
Rea
ch fa
rther
at T
ouch
dow
n (in
crea
se g
roun
d tim
e)
�St
art f
aste
r (in
crea
se h
oriz
onta
l vel
ocity
)
Strid
e R
ate
vs. S
tride
Len
gth
Star
t: St
ride
Leng
th
0
0.51
1.52
2.5 Step 1
Step 2
Step 3
Step 4
Step 5
Step 6
Step 7
Step 8
Step 9Step 10Step 11
Max Velocit
y
Stride Length (meters)
Step
Len
gth
Star
t: St
ride
Leng
th
0
0.51
1.52
2.5 Step 1
Step 2
Step 3
Step 4
Step 5
Step 6
Step 7
Step 8
Step 9Step 10Step 11
Max Velocit
y
Stride Length (meters)
Step
Len
gth
Goo
d
Bad
Star
t
Star
t: St
ride
Rat
e
012345
Stride Rate (steps/sec)
Stri
de R
ate
Goo
d
Bad
10
Star
t: St
ride
Rat
e
012345
Stride Rate (steps/sec)
Stri
de R
ate
Goo
d
Bad
St
art
Star
t: A
ir an
d G
roun
d Ti
me
0
0.050.
1
0.150.
2
0.250.
3
0.350.
4
Time (seconds)
Air
Gro
und
Star
t: A
ir an
d G
roun
d Ti
me
0
0.050.
1
0.150.
2
0.250.
3
0.350.
4
Time (seconds)
Air
Gro
und
St
art
How
Do
They
Do
It?
Und
erst
andi
ng T
he S
prin
t Pe
rfor
man
ce
Und
erst
andi
ng T
he S
prin
t Pe
rfor
man
ce
THE
MEC
HA
NIC
S O
F TH
E ST
AR
T Th
e G
olde
n St
art P
ositi
on
11
5.0
met
ers/
seco
nd
0.42
seco
nds f
rom
Sta
rt
0.5
met
ers St
ep O
ne: K
nee
Cro
ss
Spec
ific
Mec
hani
cs
Des
crip
tors
The
Star
t
Set P
ositi
on F
oot P
lace
men
t
60%
10
0%
-0.3
5
-0.3
-0.2
5
-0.2
Poor
Poor
Goo
d
Distance (m)
CO
G D
ista
nce
at S
tart
(m)
Set P
ositi
on A
ngle
s
12
Blo
ck C
lear
ance
Ang
les
Step
One
Pos
ition
s
Step
Tw
o Po
sitio
ns
The
Bre
akth
roug
h C
once
pt
Und
erst
andi
ng T
he S
prin
t Pe
rfor
man
ce
Und
erst
andi
ng T
he S
prin
t Pe
rfor
man
ce
Prop
er sp
rint m
echa
nics
are
requ
ired
to g
et
the
mos
t out
of t
alen
t and
dev
elop
men
t. •
Max
imiz
e “F
ront
Sid
e M
echa
nics
” •
Min
imiz
e “B
ack
Side
Mec
hani
cs”
Sprin
t Mec
hani
cs D
eman
ds
Sprin
t Mec
hani
cs D
eman
ds
Sprin
t Mec
hani
cs D
eman
ds
Fron
t Sid
e Fr
ont S
ide
Bac
k Si
de
Bac
k Si
de
13
0
200
400
600
800
1000
1200
0 0.
1 0.
2 0.
3
Vertical Force (Newtons)
Tim
e (S
econ
ds)
Fron
t Leg
B
ack
Leg
200
Lbs
100
Lbs
0 L
bs
Fron
t Sid
e
Fron
t Sid
e
Bac
k Si
de
Bac
k Si
de
Ver
tical
Blo
ck F
orce
s
Wha
t You
Nee
d to
Kno
w A
bout
th
e Sp
rint S
tart
Ral
ph M
ann,
Ph.
DR
alph
Man
n, P
h.D
.. R
alph
Man
n, P
h.D
Ral
ph M
ann,
Ph.
D..
Bio
mec
hani
csB
iom
echa
nics
14
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