Bird dog to hip and spinal flexion ("Bird dog" Core/pelvic floor stabilization, with hip/trunk flexion, LBP)

Start on your hands and knees, with your hands under your shoulders, and knees under your hips.
Tighten the abdominal and pelvic floor muscles.
Straighten your opposite leg and opposite arm simultaneously, making sure your maintain good control in your torso.
Do not allow your body or hips to rotate.
Hold this position, then bring both the elevated arm and leg in towards your belly button, aiming to touch your knee to your elbow.
Allow your back to bend to do this.
Extend your arm and leg again to repeat the movement.