Sprinters 'built like cheetahs'
Competitive human sprinters are built like cheetahs and greyhounds, a study has found.
Bones in the front portion of their feet are longer than those of non-sprinters, research has shown.
Their ankle joints also rotate differently due to a shorter plantarflexor moment arm (pfMA), a measurement of leverage.
Similar characteristics are found in the world's fastest sprinting animals, such as the cheetah and greyhound.
US scientists at Pennsylvania State University studied two groups of eight male volunteers, one of which consisted of sprinters who took part in regular training and races.
All the sprinters had undergone at least three years of continuous training. Six had personal best times for the 100 metre dash ranging from 10.5 to 11.1 seconds.
Magnetic resonance imaging scans were carried out of the right foot and ankle of each participant.
Author Josh Baxter and colleagues wrote: "The results ... show that there are differences in the skeletal structure of the foot and ankle between two groups of healthy subjects with different levels of locomotor performance and which also vary in the functional demands they place on their limbs.
"Sprinters were found to have significantly longer forefoot bones and shorter pfMA than those of non-sprinters..."
The research is reported in the journal Proceedings of the Royal Society B.