Women over 50 are considered seniors in terms of fitness. People's balance and functional ability tends to deteriorate around age 50. Therefore, it is advised that seniors work on doing exercises in a standing position, according to a personal fitness training manual put out by the National Academy of Sports Medicine. Standing exercises require more stabilization work for your abs and increase functional strength.
Front Medicine Ball Oblique Throw
The front medicine ball oblique throw is a standing core exercise recommended by the NASM. This exercise requires a medicine ball and a partner, although you can use a wall to bounce the ball off of instead of having a partner throw the ball back to you. Begin standing with your feet shoulder-width apart, and hold a medicine ball with your arms straight and next to your right hip. Squeeze your abs tight, and hold them in during the exercise. Bend your knees to squat toward the floor, and pull your arms behind you. Then stand up, and bring your arms forward and up to shoulder level. Release the ball, and toss it to your partner. Catch the ball, and bring your arms back toward your left hip. Repeat the exercise by throwing the ball from your left side.
The canoe is an ab exercise that mimics the upper body motion of paddling in a canoe. No equipment is needed, but you can hold a dumbbell between your hands to make the exercise more difficult. To perform the canoe exercise, stand up straight with your feet greater than shoulder-width apart and your toes turned outwards. Soften your knee joints. Clasp your hands in front of your chest, with your arms straight. Then twist your torso to the right, and pull your hands down toward your right hip, as if you were holding a paddle. Let your head follow your arms as you twist. The hips and legs remain facing forward. Return your hands up to chest level, and twist your body back to center. Next, twist to the left.
Knee Cross Crunch
The knee cross crunch exercise requires some additional coordination and balance, as you stand on one leg for brief moments. To begin, stand with your feet shoulder-width apart. Raise your left arm straight toward the ceiling and point your right foot. Then bend your left elbow, and bring your elbow down to meet your right knee as you lift your leg. Lower your toes to the floor, and lift your left arm up again. Do a complete set of your desired number of reps, and then work the other side.