There are lots of reasons to strengthen your abs. Here are 3 big ones:
1. Abs protect you. Having a strong core is crucial to avoiding injury.
2. Abs prevent back pain. If you are weak in your abs, your leg and glute muscles have to compensate, and things really start getting out of whack.
3. Abs help you excel. Whether it's golf, tennis, basketball, baseball, or any other sport, a stronger core will give you better performance. Think of how your core muscles are involved in your golf swing. If you have good strength and stability, it'll improve your swing and your distance. You can find an application for any sport.
Exercise 1: Plank on elbows
Assume a pushup position, but with your elbows bent and your weight resting on your forearms. Your body should form a straight line. Now brace your abs as if someone were about to punch you in the gut. Hold for 30 seconds. Rest 30 seconds, and repeat once.
Exercise 2: Mountain climber with hands on bench
In pushup position with your hands on a bench, brace your abs and slowly lift your left knee toward your chest. Pause 2 seconds, lower it slowly, and then raise your right knee. Alternate for 30 seconds, rest 30, and repeat once.
Exercise 3: Side plank
Lie on your left side and prop your upper body up on your left forearm. Raise your hips until your body forms a straight line from ankles to shoulders. Now brace your abs and hold for 30 seconds. Roll over onto your right side and repeat. Rest 30 seconds, and do 1 more set.
2. Intermediate Workout
Exercise 1: Plank with feet elevated
Use the guidelines for the beginner version of the exercise, but with both of your feet on a bench.
Exercise 2: Mountain climber with hands on Swiss ball
Follow the beginner instructions, but place your hands on a Swiss ball instead of a bench.
Exercise 3: Side plank with feet elevated
Do this the same way as the beginner version, but with both of your feet on a bench.
3. Advanced Workout
Exercise 2: Swiss-ball jackknife
Exercise 3: Single-leg side plank