A team from the Faculty of Kinesiology and Rehabilitation Science has used advanced laser technology to measure and analyse Olympic Champion Usain Bolt's speed during his 9.76-second performance in the 100m sprint at the Van Damme Memorial on 16 September. It was the first time the technology has been put to use in competition. The new data will provide insights into improving the training regimens of world-class sprinters.
The team from K.U.Leuven is currently putting their expertise to work at elite training centres in China (Nanjing), South Africa (Stellenbosch) and the Netherlands (Papendal). "Biomechanically, the sprint is much more complex than one might expect at first glance," Professor Christophe Delecluse said. "The position and speed of the runner changes during the race and there are also a number of phases in the race, each with differing performance-deciding factors."
"With the laser, we can accurately measure an athlete's performance at each phase of the race. From this data, we can determine where the possible weaknesses are. Bolt's race times provide perfect phase-by-phase reference points from which to base our analyses of our own sprinters."
Bolt in 2009 versus Bolt in 2011
The K.U.Leuven team was able to measure Bolt's speed 300 times per second. Bolt finished the 100 metres in a time of 9.76 seconds. His top speed was 43.99 km/h (12.22 m/s), which he achieved after 67,13 metres. So what made the difference between his time at the Memorial and his world-record time of 9.58 seconds, run in Berlin in 2009?
According to the K.U.Leuven team's findings, Bolt lost ground in three zones:
1. He lost the most time during the first 4 strides of the race in Brussels. In the first 5 meters (approximately 4 strides) Bolt achieved a speed of 21.4 km/h, while in Berlin he reached 25 km/h in the same distance. In the following 3 strides, he made up for the lost speed and performed comparably to his world-record race.
2. In Brussels, Bolt's speed peaked at the 65m15 mark while in Berlin he accelerated for another pace before his speed decreased. His average speed in the first 75 metres was approximately 0.5 km/h higher in Berlin than in Brussels. His top speed in Berlin was 44.5 km/h. In Brussels it was 'just' 43.99 km/h.
3. In the last 10 meters, Bolt's speed was 0.5 km/h faster in Berlin than it was in Brussels.
Yohan Blake: new challenger?
Even if Usain Bolt's performance at the Memorial was a touch 'weaker' than in Berlin, his phase-by-phase scores remained high. Christophe Delecluse explains: "His only 'weak point' is his start, a logical consequence of his long body. His start at the Memorial wasn't stellar either. But that's relative: if you compare Bolt to previous top sprinters, he scores between 'good' and 'excellent' in every phase while Ben Johnson, for example, shined in the acceleration phase [but less so in other phases], and Carl Lewis could rely on his phenomenal top speed."
Meanwhile, a new sprint phenom has arrived on the scene. Yohan Blake, Bolt's 20 year-old training partner, clocked a 200m time of 19.26 seconds at the Memorial, just a fraction behind Bolt's outdoor world record. "Blake had another awful start," Delecluse said. "With better reaction speed, he would have come in under Bolt's record."
"After Bolt I thought the top sprinters would fit one mould: runners with long legs who managed nonetheless to achieve high speeds. But Yohan Blake is far from tall. That's why our research remains so interesting: the elite sprinters in the men's events tend to have very different body types. The differences between each sprinter can only be revealed through a detailed analysis of each phase of their race."
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