Isolating muscles in the gym may be great for hypertrophy of that specific muscle, but it's not so great for getting better at functional movements. Why? Because muscles work together. Joints do to. Even the simple act of tilting your pelvis anteriorly, or top forward, and posteriorly, or top backwards, requires the coordinated and rhythmic movement of dozens of joints. The next time you're out on the dance floor remember that even uncoordinated dance moves need coordinated joint movements.