The three interior layers of the Earth: the crust, the mantle, and the core | Britannica

What is the Inner Core Unit? and which muscles are included

Inner Core of the Earth | Composition, Characteristics & Facts

Training the inner core is VERY important if you want to prevent low back issues, pelvic floor problems, s*xual problems, and more... - Many people have an imbalance between their outer core muscles (like the abs) and these inner core muscles because they train their outer core not the inner core. - The bad thing is people usually only become aware of and start training the inner core muscles once they start having issues like above. - An ounce of prevention is worth a pound of cure as they say.

Earth's Layers: Crust, Mantle & Core, Seismic Discontinuities - PMF IAS

The Three Layers of the Earth | Crust, Mantle & Core