Do you know of any methods to get an extra abdominal workout while walking?
You can walk with walking poles to work your abs a bit. Or you can stop periodically and do standing crunches.
Bend forward and put your hands on your thighs. Contract your abdominals as you slide your hands down your thighs slightly. Hold for a few seconds and release.
It’s great because there’s no pressure on your neck, as when you do crunches on the floor. Maintaining excellent posture while you walk, with your shoulders over your hips, will also help to tone the tummy a bit.