The QL is often overlooked but critical for spine stability. It prevents your pelvis from dropping during single-leg work and protects your lower back during loaded movements. Weak QL leads to lower back pain and poor posture. Strengthen it with side planks, suitcase carries, and unilateral deadlifts. A strong QL keeps your spine safe and your hips stable. Train it intentionally—it's the unsung hero of core stability.