Decline Bench Sit-Ups Exercise Guide

Sit-ups and crunches are isolation exercises that target the upper abdomen.

Difference Between Crunches and Sit-Ups

Sit-ups and crunches are sometimes used interchangeably, but there are some noticeable differences between these two exercises. Sit-ups are generally a larger movement compared to crunches because you are raising your torso until you reach a semi-seated position. When you perform crunches, you are raising only your head and shoulders to move your ribcage toward your pelvis, without lifting your lower back.

The crunch exercises involves only the abdominal muscles, while the full sit-up involves both the abdominals and other stabilizing muscles – in the chest, neck and low-back as well as hip flexors and lower-leg muscles (if you hook your feet). Sit-up is therefore less specific than the crunch.

How To Perform Decline Bench Sit-Ups?

STARTING POSITION (SETUP): Sit on a bench set at an incline of around 45º with your feet under the rests and your hands touching (but not holding) your head or across your chest. Initially, sit upright on the bench so that your torso is upright and perpendicular to the floor.

MOVEMENT (ACTION): Lower your torso backward until it is almost parallel to the floor. It is not necessary to lower your torso farther than horizontal to the floor or raise it beyond 90º. Return to the upright position by bending at the waist. In other words, lift your torso in a longer movement than the crunch by contracting your abdominal muscles while trying to shorten the distance between the pelvis and the chest. Raise the torso while slightly rounding the back to better focus on the rectus abdominis.

Decline Bench Sit-Ups Common Mistakes

• Too short and/or rapid movements.
• Keeping the torso rigid throughout the movement, which uses the hip flexors more than the abdominal muscles (raise the torso by rounding the back).
• Avoid jerking or accelerating through any part of the movement.

Muscles Engaged in Decline Bench Sit-Ups

• Main muscles: rectus abdominis
• Secondary muscles: external and internal obliques, psoas, quadriceps (front), transverse
  abdominal, (pyramidal)
• Antagonists: spinal erectors, longissimus dorsi and other muscles along the spinal column, lower
  back muscles, gluteus maximus

Do It Harder

As you gain strength, you can:

• increase the number of reps
• tilt the bench at a steeper angle
• hold a small weight plate on your chest

Exercise Variations

1. The Classic Sit-Ups (Floor Sit-Ups). Lie on your back with both feet flat on the floor and your knees bent to reduce stress on your spine. Place your finger tips behind your ears. Engage your core muscles and raise your torso upwards by rounding the back, leaving just your buttocks and feet on the floor. Pause at the upright position, than slowly lower your upper body to the floor back to the start position. Avoid swinging yourself up.

2. Gym Ladder Sit-Ups. Lie face-up on the ground and position the feet between two bars in the ladder, with the thighs vertical (lower legs are perpendicular to the floor), and hands behind the heat or across your chest. You can also place your finger tips behind your ears. Follow the same exercise instructions given earlier.

3. Swiss Ball Sit-Ups. Lie on your lower back on the exercise ball and place your hands (fingertips) behind your ears. Raise your upper body up from the ball and lower it back down after a short pause. Since the abdominal muscles attach the rib cage to the pelvis, your movement should focus on pulling these two body parts closer together.

4. Vertical Bench Sit-Ups. Some ab benches suspend the legs vertically. This makes the workout much more intense, but it also involves a risk of using the hip flexors too much. These benches are therefore better used only by advanced athletes whose strength and technique are up to it. Raise your torso, trying to bring the head to the knees while rounding the spine.

Summing Up

Although the sit-up is one the most popular exercise in the world for the abdominals, what most people don’t realize is that the sit-up is not a true abdominal exercise. During a 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 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. This is why too many sit-ups can lead to a strength imbalance between the iliopsoas and abdominals, as well as poor posture and lower back pain. You need to raise your torso upwards by rounding the back.