You don’t have to do situps to get abs or be fit. But it’s also not the worst exercise either. STOP doing situps like this! The key is focusing on moving upwards instead of going forwards. Sit tall! This way your hips & shoulders drive the movement instead of your spine. This exercise is also best performed at slower speeds, especially on the eccentric or lowering phase. Take 3-5 seconds going down for best results.
Start with your bodyweight or a light med ball. Exhale through the mouth going up. Inhale through the nose going down. Then hold a dumbbell in 1 hand to strengthen imbalances between sides & increase the stability demands. Hold a dumbbell in both hands for more of a strength building stimulus.
My favorite variation is the double press situp where you do 2 floor presses, situp and then do 1 overhead press. Repeat this complex for time. This is one of the best arms, abs & shoulders workouts you’ll ever do. Finally, the situp getup, where you move from ground to stand and back, is also the ultimate full-body abs exercise.