Sit with both legs straight out in front of you, feet flexed toward you. Hinge forward from your hips, reaching toward your shins or feet while keeping your back long rather than rounding it to close the gap faster. Your knees can have a soft bend if fully straight legs pull too hard on your lower back. You'll feel this along the back of both thighs, from behind your knees up toward your glutes. Let your head and neck relax rather than craning to look at your feet — where your eyes point doesn't change how far your hamstrings stretch.