LONDON, Sept 9: Researchers have discovered that the cheetah, known to accelerate to record-breaking speeds, gets its special propulsion power from its hindlimb muscles.
Japanese researchers have mapped the distribution of muscle fibre across the whole of the cheetah’s body for the first time and discovered that a sprinting cheetah is like “a rear-wheel-drive car”.
By comparing the muscles of the world’s fastest land mammal with those of a domestic cat and dog, the team identified the propulsion power of its hindlimb muscles, the BBC Nature reported.
The findings are published in the journal Mammalian Biology.
Different types of muscle fibre are suited to different activities, Dr Naomi Wada, the study’s co-author and Professor in System Physiology at Yamaguchi University in Japan, said.
In all the animals studied, so-called Type I fibres produced a small force output but were resistant to fatigue, making them best suited to maintaining posture and slow walking.
Type IIa fibre performance was best suited to fast walking and trotting whereas Type IIx or “fast” fibres created a high force output but had low endurance and were key to fast running or galloping.
“The forelimb muscles in the cheetah included [the] most Type I muscle fibres of all three animals… While the muscle of hind limb muscles have many Type IIx fibres,” Wada said.
“The functional difference between forelimb and hindlimb is the most remarkable in the cheetah,” Wada was quoted as saying by the BBC.
The team’s results suggested that the power comes from the cheetah’s hind legs, in the same way as a rear wheel-drive car, according to Wada.
The digits of the cheetah’s hindlimbs contained no fast fibres, but the digits on the front legs contained many of them.
This is because the cheetah controls its balance by using its forefeet to turn and slow down, Wada said.
With long, flexible limbs, a sprinting cheetah spends more than half its time airborne.
In order to maximise this effect, it arches and contracts its spine, and Wada and colleagues found muscle fibres that supported this technique.
The cat had a high percentage of fast fibres running along its back and middle, suggesting that it could produce a quick, strong extension of the backbone. (PTI)
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