Oblique muscles, in case you aren’t entirely sure, are situated at the side of the waist, in the area which most people tend to carry their ‘love handles’.
Anyway, you wanted to know how to perform oblique crunches. Here is how to do them:
1. Take up the crunch position, which entails feet and legs placed on something elevated, or, having the feet flat on the floor with the legs pulled in, knees upwards.
2. Place your hands behind your head, or to the sides of your ears; whichever you prefer.
3. Keeping the small of your back on the floor, rather than crunch straight forward as would normally be done, crunch diagonally as far as you can go, turning your torso into the side being crunched. (You will feel it in your obliques if done correctly.)
4. Repeat for 12 repetitions. Change sides.
5. Repeat for 3 sets.
Oblique crunches are identical to twisting crunches with the only difference being twisting crunches alternate on each repetition whilst oblique crunches do not.
Extra weight may also be added to various oblique crunches by having the weight supported on the side opposite from the one being ‘crunched’ to provide extra resistance.
A few words of warning about oblique crunches:
Old school bodybuilder and coach Vince Gironda stated that he was dead against working the oblique’s because they detracted from the V-Taper by making people look wider in the waist. If, therefore, you want the V-Taper but aren’t the narrowest person at the waist, I would advise against them.
If you are building your body for power and performance, though, and not mere cosmetics, then there is no such thing as a useless muscle. Have at it.