Brown Bear Muscle fibres and Energy Intake

[Granolah]

I’ll add info about the opposing title

[Granolah]

Muscle fibres

www.researchgate.net/publication/23261451_Enzyme-_and_Immunohistochemical_Aspects_of_Skeletal_Muscle_Fibers_in_Brown_Bear_Ursus_arctos

^ While this paper only provided Muscle Fiber properties for only 3 muscle groups (forelimb, back, and hindlimb), it does at least give us some ideas of fiber properties in Bears. As you can see, adult Bears (B3) have about 55-63% of slow Type I fiber and about 37-45% of fast Type II fiber. So while the percentage of fast twitch fiber in Bears may not be as high as that of Big Cats, it's not as low as what your source suggests.

www.researchgate.net/publication/23261451_Enzyme-_and_Immunohistochemical_Aspects_of_Skeletal_Muscle_Fibers_in_Brown_Bear_Ursus_arctos

Percentages of muscle fiber types in individual muscles of all three bears Type I (MHC-I) Type IIC (MHC-I/IIa) Type IIA (MHC-IIa) Type IIAX (MHC-IIa/x) Type IIX (MHC-IIx)

Henry Harlow and his colleagues at the University of Wyoming found that the bears lost only 22 per cent of their muscle strength during hibernation , and only 10 to 15 per cent of their protein ( Nature , vol 409 , p 997 ) .

www.newscientist.com/article/mg16922794-300-let-sleeping-bears-lie/

[Granolah]

Here’s some from the BoldChamp

Another study on the fast twitch of Lions:

open.uct.ac.za/bitstream/handle/11427/24478/thesis_hsf_2016_feldmann_daneil.pdf?sequence=1



Compare it to the bear data.

[OldGreenGrolar]

There are two types of muscles. The fast twitch and slow twitch muscles.

[arctozilla]

The muscle fibers you posted are those in the locomotor muscles, which are used for speed, not in the upper body muscles, which are used for physical strength. Even polar bears and black bears, who have pound for pound weaker limbs than brown bears due to lacking shoulder hump, have great amout of fast twitch fibers in the upper body.