Usain Bolt could run the 100m dash in 9.44s, given the right legal conditions, claims Cambridge mathematician, Professor John Barrow…if only he could get off the starting blocks a little bit quicker.
The Acceleration Phase (0-30m)
Unfortunately for Bolt, the sprint start and the acceleration phase account for 64% of the total result in the 100m dash. This creates a major disadvantage for taller sprinters, who are often poor starters.
Bolt’s reaction times are generally much slower than the 0.1s allowed and physics noticeably hampers him during the acceleration phase.
The acceleration is proportional to the force produced when pushing off the blocks but there is an inverse relationship between acceleration and body mass.
This means that height is a disadvantage because the force also has to overcome the drag produced by a bigger body.
Sprinters with well-developed, strong muscles attached to shorter limbs promote more rapid movements and a greater force, which gives them an initial advantage.
Maximum Velocity Phase (30-60m)
During this phase the runners are upright, well away from the blocks and are attempting to reach their top speed, which is achieved through a combination of stride length and stride rate.
This is where a taller sprinter has the potential to catch up – long limbs and good flexibility alone achieve half of the speed formula.
Bolt’s gangly limbs suddenly become an advantage, meaning he can reach 44km/h during this phase and can pull ahead, despite his poor start.
It also explains why Bolt does not achieve the same kind of success in the 60m dash as he does at longer sprint races: he is still catching up at the beginning of this phase!
Speed Maintenance Phase (60-100m)
The final phase is all about speed maintenance and Bolt himself has stated that if he is ahead at 60m, the other contenders simply don’t stand a chance.
Bolt is able to maintain his pace exceptionally well and in the Olympic 100m final Bolt completed the race in just 41 steps, compared to Blake’s 46 steps.
In the 200m final Bolt’s poor start will be even less of a factor…Thursday 9th at 8.55pm BBC1