Bear and bigcats anatomy

[brotherbear]

Parvez says:  They instead chose to be omnivores(which is smart, a very good move if you ask me) and retain their body strength through some means like hard work(as @brotherbear said) and feeding on soft tissues.
*No Parvaz; I said that the grizzly's shoulder hump evolved after hundred's of thousand's of years of hard work, mainly digging, as a species. Bears have no problem with retaining their muscle mass.
http://jeb.biologists.org/content/jexbio/215/12/2081.full.pdf 

SUMMARY

Hibernating bears retain most of their skeletal muscle strength despite drastically reduced weight-bearing activity. Regular neural

activation of muscles is a potential mechanism by which muscle atrophy could be limited. However, both mechanical loading and

neural activity are usually necessary to maintain muscle size. An alternative mechanism is that the signaling pathways related to

the regulation of muscle size could be altered so that neither mechanical nor neural inputs are needed for retaining strength. More

specifically, we hypothesized that muscles in hibernating bears are resistant to a severe reduction in neural activation. To test this

hypothesis, we unilaterally transected the common peroneal nerve, which innervates ankle flexor muscles, in hibernating and

summer-active brown bears (Ursus arctos). In hibernating bears, the long digital extensor (LDE) and cranial tibial (CT)

musculotendon masses on the denervated side decreased after 11weeks post-surgery by 18±11 and 25±10%, respectively,

compared with those in the intact side. In contrast, decreases in musculotendon masses of summer-active bears after denervation

were 61±4 and 58±5% in the LDE and CT, respectively, and significantly different from those of hibernating bears. The decrease

due to denervation in summer-active bears was comparable to that occurring in other mammals. Whole-muscle cross-sectional

areas (CSAs) measured from ultrasound images and myofiber CSAs measured from biopsies decreased similarly to

musculotendon mass. Thus, hibernating bears alter skeletal muscle catabolic pathways regulated by neural activity, and
exploration of these pathways may offer potential solutions for disuse atrophy of muscles. Reply