There is a world somewhere between reality and fiction. Although ignored by many, it is very real and so are those living in it. This forum is about the natural world. Here, wild animals will be heard and respected. The forum offers a glimpse into an unknown world as well as a room with a view on the present and the future. Anyone able to speak on behalf of those living in the emerald forest and the deep blue sea is invited to join.
The cursoriality and locomotion topic is a bit convoluted. One can pick one trait of an organism and attribute it to a certain locomotion and sound accurate, but then another similar trait of another organism results in a completely different, unexpected behavior and things stop making much sense.
The extremely sloped back of S. populator and somewhat sloped back of S. fatalis do not seem favorable to much high intensity running in my head, it just seems a bit off balance. Having proportionately longer proximal long bones (humerus, femur, the bone more associated with mass of the body's core) than distal long bones also makes the much running or sprinting less likely, as to be a runner or a sprinter, you'd want more ulna/tibia (the light bones which increase stride), than femur/humerus. Spoor (1986) attributes sloped backs to the assignment of the center of mass, where "In hyenas it is situated more cranial than in other large carnivores due to the heavy musculature of the fore limb, the long neck and the powerful jaws." S. populator has the first two characteristics of the hyena. Maybe it used the frontal center of mass in pinning down prey better, reducing risk to its canines.