9.69 is the magic number
Words were barely required by anyone watching Usain Bolt break Asafa Powell’s world record whilst winning the 100m in Beijing last month. A gasp or yell as he blew away the field and cruised across the line, arms spread wide, was as eloquent as anything else. Seeing, on that unforgettable night, was believing.
But if words were superfluous, what about numbers? Only one figure really counted, of course, and that was 9.69. But captured within it was the story of Bolt’s run, and now, after some analysis by Elio Locatelli of the IAAF, that story can be told.
First, Bolt’s run was broken down into 10 metre increments. Three figures - his reaction time from the block, his time over the first 10 metres and over the last 10 - were measured officially, whilst the distances inbetween were expertly simulated to produce a theoretical speed distribution for Bolt’s run. The breakdown was (in seconds):
Reaction time 0.165
0-10m 1.70
10-20m 1.00
20-30m 0.90
30-40m 0.87
40-50m 0.85
50-60m 0.84
60-70m 0.82
70-80m 0.83
80-90m 0.85
90-100m 0.86
Final time 9.685
Some astonishing data came out of the analysis, most notably the speed at which Bolt was travelling as he crossed the finish line. Although he visibly slowed down as he celebrated his win, his momentum was such that he still covered the final 10 metres more quickly than any 10 metre stretch in the first 40 metres of the race. In fact, had he crossed the line a thousandth of a second earlier, his actual time of 9.685 would have been rounded down to 9.68 rather than up to 9.69. Overall, Bolt covered 10”32 metres per second during the run, and 11”49 metres per second after the first 10 metres of the race.
The analysis also studied the number of strides Bolt took to cover 100 metres – 41.05. Although height has never been considered particularly beneficial to a sprinter, Bolt’s length of stride, combined with speed of foot, offered a considerable advantage. Asafa Powell’s previous world record of 9.74, set in Rieti, Italy, saw him take 43.5 strides to cover 100m. In the Olympic final, where he clocked 9.95, Powell required an additional stride – 44.5 – to cover the ground.
The figures also indicate that Bolt could run considerably faster in the future. His reaction time at the gun of 0.165 compared unfavourably to Powell’s, both in Rieti (0.137) and Beijing (0.134). Also, had Bolt continued running flat out to the tape, he would have recorded a time in the low 9.6s. It’s such a time that Asafa Powell has vowed to run to reclaim the record.
Stats like these serve to show how remarkable Usain Bolt is. At 22 years of age, his best years lie ahead and yet he has already redefined the boundaries of sprinting. The true joy, though, remains in watching rather than counting.