Weighted Decline Crunch

The Sit-Up is a “classic” abdominal exercise (see technique). The exercise contains two important elements: rounding the back and raising the upper body.

The rectus abdominis (the basis of the “six-pack”) pulls the sternum toward the pelvis by rounding the back.

The rectus femoris brings the thigh toward the pelvis and the lower spine, and vice versa. It is a so-called hip flexor and, in a standing position, brings the thigh forward from the hip joint. In the lying position of the Sit-Up, this brings the entire upper body toward the legs. The weaker sartorius assists the rectus femoris. Shorter muscles that connect the pelvis to the thigh, the psoas major and iliacus, also play an important role in flexion from the hip.

The oblique abdominal muscles on the sides stabilize the core throughout the exercise by braking lateral tilting and rotation. The transversus abdominis (beneath the obliques) pulls the abdominal wall inward and thus acts as a natural weightlifting belt to stabilize the core.

The reclined position ensures that tension is maintained longer throughout the movement. In this variation, you add extra weight by holding a weight plate. This can be done with your arms extended, or with the plate held high on your chest.

Weighted Decline Sit-Up execution

Remove any dumbbell from the rack.

Lie down with the weight plate on the decline bench and ensure that your lower legs are firmly secured between the leg pads.

Place the weight plate as high as possible on your chest. This is your starting position.

Bring your chest toward your pelvis by tightening your abdominal muscles. Focus on curving the spine (rounding the back). Keep looking upward to prevent the neck from curving as well. Your upper back has now lifted off the bench.

In one smooth movement, continue raising the rest of your upper body until you feel little resistance.

Slowly return your upper body downward and backward.

Stretch your back until you almost touch the bench.

Weighted Decline Sit-Up

Active muscles:

Abdomen:

Rectus abdominis
Obliquus externus abdominis (external oblique)
Obliquus internus abdominis (internal oblique)
Musculus transversus abdominis (transverse abdominal muscle, or “corset muscle”)

Pelvis:

Psoas major
Iliacus

Legs:

Rectus femoris
Sartorius

Weighted Decline Sit-Up technique

For a six-pack or injury prevention?

Strong abdominal muscles are indispensable for a strong core and preventing, among other things, lower-back pain. In practice, many people do abdominal exercises mainly for a better-looking abdomen. Often, a tight abdomen or six-pack is the ultimate goal. In most cases, you do not need abdominal exercises for a flat stomach or six-pack. These are mainly caused by a low body-fat percentage. You cannot specifically burn fat in the abdominal region, including through abdominal exercises. So, as the old saying goes, you mainly make a six-pack in the kitchen.

At a low body-fat percentage, abdominal exercises can make a visual difference. Thicker muscle bellies in the rectus abdominis then create deeper lines in the abdomen. However, the abdominal muscles are used and therefore trained during many different exercises and daily activities. For most people, a low body-fat percentage is therefore enough for a six-pack. In some exceptional cases, the muscle bellies (the “blocks”) in the rectus abdominis are so flat that they are barely visible, even at a low body-fat percentage. Very superficial intermediate tendons and a linea alba that divide the muscle bellies can also contribute to this. In those cases, it may be useful to do abdominal exercises for appearance.

Sit-Ups or Crunches?

As mentioned, you can divide the Sit-Up into two movements. In the second part of the movement, the aforementioned muscles in the legs and pelvis play an important role. Sit-Ups are often performed for stronger or better-looking abdominal muscles. However, the Sit-Up also places a greater load on the spine while the abdominal muscles themselves work less hard than during a Crunch. In this case, “a classic exercise” therefore partly means “outdated.” Sit-Ups have lost considerable popularity in favor of the Crunch, which is effectively only the first part of the Sit-Up.

At a glance