The oblique muscles sit adjacent to your main abdominal muscles, and are often simply referred to as ‘side abdominals’.
These muscles are what allow you to bend sideways and to twist your torso.
If you develop strong obliques, not only will you have a slimmer waist, you will improve your posture and help avoid lower back problems.
A fairly standard exercise used by many gym instructors in abdominal strengthening routines is the oblique crunch.
This movement requires repeated contraction of the oblique muscles, forcing them to grow.
Lie on the ground as if you were to do a normal crunch. Bend your knees and fold them to one side, keeping the top knee in line and stacked on top of the bottom knee.
Put your fingers on your temples, and slowly raise your torso off the ground. You should be trying to ‘crunch’ your ribs towards your pelvis. Slowly return to the ground.
Do three sets of five (beginner), three sets of ten (intermediate), or three sets of fifteen (advanced).