The Rooboard V Sit-up with a leg lift could be the best exercise ever for total core strength. Firstly the Rooboard creates instability which forces the core muscles to engage to maintain stability.
Secondly, holding the legs in a straight leg position while performing a leg lift promotes a full range of motion through the entire abdominal area. This includes the upper and lower abs regions and the obliques.
If you only have time to perform one exercise for your abs – this is the exercise you need to be doing.
Some More Ab Workouts
Four Plank Exercises For Core Strength and Improved Posture
Improving abdominal and lower back strength is vital for good posture and avoiding lower back pain and injury. The plank exercise and its many variations are the perfect exercise for this. Exercises here.
Four Exercise Upper and Lower Abs Workout
By isolating the abdominis muscle first and then performing targeted exercises for the ‘upper’ and ‘lower’ abs you will build a strong core and if your body fat is low enough – the washboard or six pack abs look.. Full workout here.