HSE311 - Performane Analysis of 100m sprint
Transcript of 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>.>