Reach across, tap the toe, light up your obliques.
Lift your shoulder blade off the floor, do not yank your neck to reach.
Reaching one hand across your body to a raised opposite toe combines a crunch with rotation, so the obliques fire alongside the upper abs on every rep. Only one leg is up and one arm is reaching, which makes each side earn its reps separately and exposes any left-right gap in your trunk. The controlled lower back down is half the work, resist it instead of flopping.
Yes, the crunch and reach are the exercise, the touch is just a target. Reach as high up the leg as you can with your shoulder blade off the floor, the range will come.
A soft bend is fine if your hamstrings are tight, it keeps the leg from creeping toward your face mid-set. Straighten it over time as your flexibility improves.
The regular version reaches both hands to both raised legs, straight up the middle. The opposite-side reach adds rotation, which pulls the obliques into what is otherwise an upper-ab move.
