توضیحات:

"Core Strength: Your Ultimate Guide To Core Training!

Strengthen your core muscle to build a better body.

The Complete Step By Step Guide to a Stronger Body & Better Posture for Men & Women.

The best core exercises may surprise you. It's not enough to just do ab crunches and sit ups. To build a strong core you need to exercise a variety of muscles, from your hips to your shoulders.

Develop a stronger core with these beginner, intermediate and advanced exercises."