While it's true that situps have gotten a bad reputation over the years as the cause of back and neck pain, those are complex issues, and a healthy individual should be able to perform them pain-free.
Here are a few tips to make sure you are doing situps correctly:
1. Keep your head neutral and chin slightly tucked. Oftentimes, people whip their head back and forth during the situp, which can lead to neck tension or strain. Your neck should stay in line with your spine as you move. It's your abs doing the heavy lifting, not your neck.
2. Speaking of whipping, don't just flail your body up and down. You should use your abs to rise and maintain a contraction as you control your descent.
3. Think of your spine you want to avoid excessive flexion of the lower back. You should have mobility in your upper and mid back, so you can contract at the top like a crunch, but your lower back should stay neutral and not curve into a C-shape.
4. "Quality over quantity" should be your philosophy with all exercise, but pay special attention to it here. You want to make you aren't racing to get the most reps at the expense of proper execution. After all, if you end up flapping like a fish out of water, you aren't working the muscles the situp was designed for anyway. So work on quality reps, and if your form starts to collapse, pause and regroup.
The video above shows 12 different situp variations that will make you a believer again, some with a greater level of difficulty than others. The bent-knee situp and the eccentric situp are great for everyone, however, they are especially good to start with if your core strength needs work since they will allow you to focus on controlling the movement.
If you are a situp champion, the v-up and straight leg situp will challenge your abs and hip flexors, and the bench reverse crunch will enhance core stability. There's a reason Rocky did a hardcore version of these before fighting Drago.
And you don't want to forget your obliques . The twisting situp will bring your them into the mix and contribute to a shredded v-taper.
So if you're looking to get those abs into fighting shape, make sure to include these situps in your regular core routine.
(And if these aren't enough of an ab-burner for you, try Men's Health Anarchy Abs for five intense, fat-burning workouts you can do from home.)