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Page 1: HSE311 - Performane Analysis of 100m sprint

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Mero,  Komi  and  Gregor  (1992)  identify  reaction  time,  force  production  by  acceleration  

(through  stride  frequency  and  length)  and  overall  force  production  as  being  some  of  the  key  

components  that  dictate  success  in  sprinting  performance.  As  such,  these  will  be  the  focus  

of  this  analysis  of  Johan  Blake’s  100  metre  sprint  performance  at  the  London  Olympics  final  

in  2012.  

 

Reaction  time  

 

Reaction  time  was  measured  from  the  first  initial  movement  of  the  athlete  until  their  lead  

leg  leaves  the  ground  at  the  beginning  of  the  race.  Usain  Bolt’s  reaction  time  was  measured  

at  .36  of  a  second,  whereas  Johan  Blake’s  reaction  time  was  measured  at  .40  of  a  second.  

 

 

 

Stride  frequency  

 

Usain  Bolt  completed  41  strides  across  100m,  whereas  Johan  Blake  completed  46  strides  

across  100m.  This  was  determined  by  counting  the  number  of  strides  of  each  athlete  from  

their  first  stride  at  the  start  to  the  final  stride  within  the  100  metre  distance.  Stride  length  

was  measured  from  the  athlete’s  toe  of  their  back  foot  to  the  toe  of  their  front  foot  during  

the  last  10  metres  of  the  race,  ascertained  by  the  lines  of  measurement  on  the  track.  

 

 

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Stride  length  

 

At  the  same  point  in  the  race  (14.02  metres  to  go  before  the  finish  line),  Usain  Bolt’s  stride  

length  was  2.17  metres,  whereas  Yohan  Blake’s  stride  length  was  1.63  metres.  This  was  

calibrated  according  to  the  IAAF’s  track  measurements  (IAAF,  2015).  Based  on  stride  

frequency,  Bolt’s  average  stride  length  (taking  into  account  a  short  first  stride)  was  2.43  

metres,  whereas  Johan  Blake’s  average  stride  length  was  2.17  metres.  

 

 

 

Time  per  stride  

 

Usain  Bolt’s  time  was  9.63  seconds  for  100m,  whereas  Johan  Blake’s  time  was  9.75  seconds  

for  100m.  Based  on  total  time  and  stride  number,  Usain  Bolt  made  a  stride  every  0.23  

seconds,  whereas  Yohan  Blake  made  a  stride  every  0.21  seconds.    

 

Height  and  weight  of  the  athletes  

 

According  to  ESPN  (2015),  Yohan  Blake  is  180cm  and  weighs  84  kilograms.  The  same  source  

(ESPN)  states  Usain  Bolt’s  height  as  196cm  and  weight  as  86kg.  

 

In  terms  of  this  analysis,  reaction  time,  stride  frequency,  stride  length  and  time  per  stride  

are  considered  the  key  components  of  such  a  short  race  duration  as  mentioned.  Through  

analysis,  apart  from  these  variables,  there  was  little  to  distinguish  the  performances  of  Blake  

and  Bolt.  Considering  the  advantages  that  Bolt  had  with  these  key  variables  during  the  race,  

the  result  was  quite  close  between  the  two  runners.  

 

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Summary  table  of  results:  

  Yohan  Blake   Usain  Bolt  

Reaction  time   0.4  seconds   0.36  seconds  

Stride  frequency   46  strides   41  strides  

Stride  length  (last  10m)   1.63  metres   2.17  metres  

Time  per  stride   0.21  seconds   0.23  seconds  

Height  +  Weight   180cm  +  84kg   196cm  +  86kg  

 

Key  information  for  Yohan  Blake’s  coach:  

 

• In  a  race  that  was  decided  by  0.12  of  a  second,  Blake’s  reaction  time  of  0.4  seconds  

as  opposed  to  his  counterpart  Bolt’s  reaction  time  of  0.36  is  an  area  for  

improvement.  Blake’s  reaction  time  at  the  beginning  of  a  race  needs  to  be  quicker  to  

get  at  least  an  even  start  with  his  competitors,  or  ideally  a  head  start.  This  needs  to  

be  achieved  using  whichever  means  available  to  him  (music,  caffeine,  pre-­‐race  

routine  etc)  

• Having  a  height  advantage  and  thus  a  greater  stride  length,  Bolt  is  always  going  to  

have  an  advantage  over  Blake.  A  greater  stride  frequency  means  he  is  making  

contact  with  the  ground  more  frequently  than  Bolt,  and  thus  decreasing  the  time  

where  he  is  moving  forward  towards  the  finish  line.    

• The  increased  stride  length  of  Bolt  over  Blake  is  also  an  advantage  as  he  is  making  

contact  with  the  ground  for  less  time  than  Blake  and  thus  is  making  more  forward  

progress  towards  the  finish  line.  There  is  a  maximum  stride  length  that  an  athlete  

can  reach  due  to  the  length  of  their  limbs,  however  Blake  should  aim  to  reach  this  

maximum  length  consistently  throughout  a  race,  particularly  at  the  beginning.  This  

will  decrease  his  stride  rate  and  time  making  contact  with  the  ground,  which  will  be  

advantageous.  

• As  already  mentioned,  Blake’s  height  differential  to  his  competitors  means  his  stride  

length  is  decreased  and  his  stride  rate  is  increased,  and  he  also  weighs  less  than  

Bolt.  He  obviously  cannot  increase  his  height,  however  he  can  potentially  diminish  

this  disadvantage  by  weighing  more  than  his  competitor  –  specially  increasing  cross-­‐

sectional  area  and  muscle  mass  of  his  lower  body  to  increase  strength  and  power  

output.  By  doing  this,  he  could  potentially  increase  the  power  generated  as  he  

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makes  contact  with  the  ground,  resulting  in  more  forward  momentum  and  a  better  

race  performance.  

 

Limitations  of  the  analysis:  

• Due  to  the  camera  angles,  it  was  difficult  to  get  a  good  view  of  the  two  athletes  

together  at  the  same  point  in  the  race,  particularly  for  the  purpose  of  comparing  

stride  length  and  calibrating  a  distance  on  the  track,  

• The  presence  of  other  competitors  on  the  track  often  obscured  the  analyst’s  view  of  

Johan  Blake  during  the  race,  making  accurate  analysis  quite  difficult,  and  

• The  resolution  of  the  footage  is  grainy  in  some  parts,  making  limbs  of  the  athletes  

blurred  which  made  it  difficult  to  locate  anatomical  points  on  athletes  to  provide  

accurate  measures  of  variables  such  as  stride  length  and  reaction  time.  

 

Link  to  annotated  video:  

http://air.deakin.edu.au/public/media/HSE311+Performance+Analysis+Video+-­‐

+Samuel+Ryan+-­‐+211338161/0_bhy46igf.    

 References:    ESPN  2015,  retrieved  28  May  2015,  <http://espn.go.com/olympics/summer/2012/athletes/_/athlete/52386/usain-­‐bolt>.    ESPN  2015,  retrieved  28  May  2015,  <http://www.iaaf.org/athletes/jamaica/yohan-­‐blake-­‐208640>.    Mero,  A,  Komi,  V,  &  Gregor,  R  1992.  ‘Biomechanics  of  sprint  running’,  Journal  of  Sports  Medicine,  vol.  13,  no.  6,  pp.  376-­‐392.    IAAF  2015,  retrieved  28  May  2015,  <http://www.iaaf.org/about-­‐iaaf/documents/technical>.>