Primary muscle injury as a result of rapid turns and twists inherent in a sporting dog's lifestyle would be more likely than the typical routine of a companion animal. (veterinaryevidence.org)
Ideally, exercise stations should alternate so that the same primary muscle groups are not used consecutively. (onnit.com)
Primary muscles used in the crunch include rectus abdominis, the six pack muscles, and oblique's, similar muscles used in planks. (fitwirr.com)