You're right that achieving a lean midsection can be challenging for many women. While men and women's muscles are not significantly different, there are some anatomical differences that can make it harder for women to get flat, firm abs. Women generally have a wider pelvis and a longer waist, which can affect the appearance of the abdominal area.

To achieve visible abdominal muscles, it's important to go beyond standard sit-ups and incorporate a well-rounded approach to your fitness routine. Here are some tips that can help:

1. Full-body strength training: Engaging in strength training exercises that target various muscle groups, including the core, can help build overall muscle tone and increase your metabolic rate. Compound exercises like squats, deadlifts, lunges, and push-ups are effective for developing core strength.

2. Cardiovascular exercise: Incorporating cardiovascular exercises such as running, swimming, cycling, or HIIT (high-intensity interval training) workouts can help burn calories and reduce overall body fat, including in the abdominal area.

3. Planks and variations: Plank exercises are excellent for engaging the entire core, including the deeper muscles. Try variations such as side planks, plank jacks, or mountain climbers to challenge your core from different angles.

4. Pilates and yoga: These disciplines focus on core strength, stability, and flexibility. Practicing Pilates or yoga can help improve your posture, strengthen your core, and create a longer and leaner appearance.

5. Balanced diet: No matter how much you exercise, it's essential to maintain a balanced diet to support your fitness goals. Focus on consuming nutrient-dense foods, including lean proteins, whole grains, fruits, vegetables, and healthy fats. Limit processed foods, sugary drinks, and excess sodium intake, as they can contribute to bloating and water retention.

6. Consistency and patience: Building visible abdominal muscles takes time and consistency. Stick to your exercise routine and make healthy choices consistently, and over time, you will start to see progress.

Remember, it's important to listen to your body, work within your capabilities, and consult with a healthcare professional or fitness expert before starting any new exercise program, particularly if you have any underlying health conditions or concerns.

The exercise you're describing is commonly known as a Swiss Ball crunch or stability ball crunch. It is indeed an effective way to target the upper abdominal muscles. Here's a step-by-step guide on how to perform this exercise:

1. Start by positioning the Swiss Ball on the floor and sit on it with your feet flat on the ground.
2. Slowly walk your feet forward while leaning back, until your lower back is resting comfortably on the ball. Your thighs and torso should be parallel to the floor, forming a 90-degree angle at your hips and knees.
3. Place your hands behind your head, elbows pointing out to the sides, or lightly touching your temples. This will support your neck throughout the movement.
4. Engage your abdominal muscles and gently curl your torso upward, lifting your shoulder blades off the ball. Exhale as you perform this movement.
5. Focus on contracting your upper abdominal muscles, avoiding excessive neck strain or pulling with your arms.
6. Pause briefly at the top of the movement and then slowly lower your torso back down to the starting position while inhaling.
7. Repeat the exercise for the desired number of repetitions, usually 10-15 for beginners, and gradually increase as you become more comfortable and stronger.

Remember to maintain a slow and controlled movement throughout the exercise, avoiding any jerking or sudden motions. It's essential to listen to your body and adjust the difficulty by either changing the position of your feet on the ball or adding more repetitions rather than compromising your form.

As always, it's a good idea to consult with a healthcare professional or certified fitness instructor before starting any new exercise routine, especially if you have any pre-existing medical conditions or concerns.