He's broken the 100m world record three times and the 200m world record twice - but can Usain Bolt run even faster? Judging by the way he slowed down at the Olympic 100m final 10m from the finish, there's room for improvement.
His form, according to his coach Glen Mills, isn't perfect. Bolt needs to eradicate lateral movement of the torso when he's pumping his arms. If he sorts this out, what is his potential? "I've heard that the fastest man can go is 9.4 seconds for 100m," says Bolt. "I think it's possible for me to run that."
The perfect form
RW contributing editor and coach Nick Anderson (runningwithus.com) explains how you can achieve the perfect running form (and high speeds) when sprinting:
Keep your shoulders down and relaxed, and your head upright in line with the rest of the body. Keep the shoulders straight and avoid lateral rotation.
Pretend you're being pulled upwards by a string at the top of your head to achieve hip height. A strong mid-section is needed to keep them there and prevent collapse on impact.
Push your knees forwards and up high. This will generate more power, encourage a longer stride and cover more distance.
When the foot is coming towards the ground, lift the toes up towards the shin so your foot is horizontal. You should land on the midfoot, with the foot underneath the body, not in front.
Arms should be loosely held at right angles and driven back at the elbow as far as possible. On the swing back forwards, pump your hands to shoulder level.
These should come off the floor and travel high in an arc towards the bum, almost flicking it, before travelling through to the front.