Jefferson Curl

Stand on a low step or block with your feet hip-width apart and your knees soft. Starting from your neck, round your spine forward one vertebra at a time, letting your head lead and your arms hang loose, until you're curled all the way down toward your shins. This is a slow segmental roll, not a hip hinge — your lower back is meant to round here, unlike in most other exercises. Reverse the roll to come back up, stacking your spine from your lower back to your neck in the same unhurried order. Keep your knees soft rather than locked so the stretch loads your spine and hamstrings rather than your knee joints. If any point feels sharp rather than stretched, back off the range you're rounding into.