Dead bugs are the finest core-strengthening workouts for ladies. This is a great core exercise.
It also aligns your pelvis so you can work out properly and maintain excellent lower back posture.
A decent plank will strengthen your abs and teach you to breathe through your nose while maintaining proper posture.
Side planks engage your transverse abdominis, the deepest core muscle that protects your lower back throughout daily activities and strenuous exercise.
Instability from exercise balls increases core muscle demand. A "body saw" increases lever length, which elevates your workout.
This technique uses the exercise ball to produce instability from all directions, strengthening your core in several ways.
It encourages you to move your arms while strengthening your core, which applies to many daily tasks.
Conventional crunches strain your neck as you bend forward to finish each exercise. Rounding shoulders worsens posture.
Do the reverse crunch to work your external obliques and "tuck" your pelvis for proper posture.