The straight-arm cable pulldown is an underappreciated lat exercise. Maybe you've tried but just didn't "feel it" in the right places. Let's fix that.
The wrists are bent in extension, the neck and low back are in extension too, and the elbows are locked. These positions aren't great for engaging the lats. They really just light up the triceps, posterior shoulder muscles, and low back.
Straighten the wrists and think of pointing the knuckles forward as if you're throwing a punch. Bring the upper ribs down and engage your abs to keep your lumbar spine neutral. Slightly tuck your chin and pull your head back to keep a long, straight neck.
Bend your elbows slightly and lead with them to bring the bar toward your upper thighs. These simple adjustments will completely change the way you feel this exercise.