Decline Bench Twisting Sit-Up Exercise Guide

The twisting sit-up (oblique sit-up) is a great exercise to target your oblique abdominal muscles. The twisting sit-up is an advanced form of  sit-up. You can either use an incline sit-up bench or perform them on the floor.

The technique is similar to the basic sit-up, but you twist the torso as your raise it to bring in the internal oblique on the side contracted and the external oblique on the other side (as well as the other flexors). While raising and rotating the torso, you also need to bring the ribs and the pelvis closer together. The combination of flexing and rotating the torso may be inadvisable in some cases. Just like the other sit-up variations, make sure you’re performing the exercise correctly.

Exercise Instructions – Proper Exercise Technique

This exercise is a variation of the decline bench sit-up.

Sit on a bench set at an incline of around 20-degree and position (secure) your feet under the roller pad with the backs of your knees on the knee pad. Position your hands behind your head (fingers interlocking) with your elbows pointing outward.

As you sit up, twist your torso, directing your right elbow toward your left knee. Feel the contraction in your right oblique muscles. Hold for one second, then lower back down to the starting position. During the second repetition, direct your left elbow toward your right knee to work your left oblique muscles. Repeat, alternating between left and right sides. As you gain strength, increase the number of reps, or tilt the bench at a steeper angle.

Twisting Sit-Up Tips & Key Points

• Your torso should be vertically upright in the top position, with one elbow almost touching the opposite knee.
• Lower your torso until almost parallel to the floor, about three-quarters of the way down. Do not lean back too far – this releases tension from the abdominals and places unnecessary stress on the lower back.

Target Muscles

This move (twisting sit-up) primarily works your obliques, but half a dozen other muscles are recruited to assist and stabilize your body.

Primary muscles: rectus abdominis, external oblique, internal oblique
Secondary muscles: serratus anterior, hip flexors (sartorius, iliopsoas, rectus femoris)

Exercise Variation

• Twisting Sit-Ups on the Floor. Start flat on your back on an exercise mat or a thick carpet, with your knees bent at least 90 degrees, feet flat on the floor, and hands behind your head. By contracting the abdominal muscles, first bring your head, then your chest off the floor, twisting as you rise so that you can touch one elbow to the opposite knee. Return to the starting position, then repeat, touching the opposite elbow to the other knee.

• Medicine Ball Twists. Lay on the floor with your knees bent and feet on the floor (you can also raise your legs off the floor for variation) while holding a medicine ball to your chest. Raise your body up by using your core muscles so your torso is about a 45 degree angle from the floor. Without dropping your legs or arms bring the medicine ball to one side, twisting as far as you can. Twist to the opposite side as quickly as possible, and repeat.

Replacement Exercises

Try these other exercises targeting the same primary muscle group – internal and external oblique muscles.

• Cross-Over Crunch
• Lateral Crunch
• Lying Oblique Reach
• Broomstick Twist
• Bicycle Crunch Exercise
• Russian Twists

Conclusion

Great care and excellent technique are required to strengthen the oblique abdominal muscles with twisting sit-ups. If you can’t do the basic sit-up with proper form, you probably can’t do any of the other fancy variations with proper form either and you won’t benefit much from them either.

During the twisting sit-up, your main trunk flexor, the iliopsoas muscle, often does the majority of the work while the abs are not optimally recruited. Because the iliopsoas muscle originates on the lower back, the twisting sit-up literally pulls on the lower back with every repetition, especially if your feet are held down or anchored, or the repetitions are performed quickly in a jerky fashion. So for bodybuilders, we recommend twisting crunches (cross-over crunches) over twisting sit-ups. If you decide to perform this exercise than it would be a good idea to rest your legs on a flat exercise bench or other elevated platform to isolate your abdominals from the assistance of your hip flexors during the twisting sit-up exercise.

Adding rotation (twist) to relevant abdominal exercises such as a sit-up (curl-up) will cause greater challenge to the oblique abdominal muscles. When one is performing a straight sit-up, both sides of the external oblique and internal oblique muscles can act with the rectus abdominis. However, when rotation (twisting motion) is added, some of the obliques are antagonists to the movement, and only the internal oblique on the same side as the direction of movement and the external oblique on the opposite side of the direction of the movement can aid with the movement.