October 19, 2026, 3:45 pm | Read time: 3 minutes
The crunch machine comes in many different versions and under various names. From ab press to ab machine to sit-up device. However, the principle is always the same. Below, we explain how to use the machine correctly and why it is so effective for shaping your abs.
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These Muscles Are Trained
The star is the rectus abdominis. These are the muscles most people think of when they envision a six-pack. They provide the typical, striking look. Additionally, the pyramidalis muscle is also trained. It is located in the lower part of the abdominal wall in front of the rectus abdominis. Furthermore, the oblique abdominal muscles are involved. When using the machine, both the internal and external oblique muscles work together. They support the rectus abdominis in bending the upper body and help keep the torso stable during the exercise.
Pay Attention to Proper Execution
Start by sitting upright in the machine. Grasp the designated handles loosely, without pulling with your arms. Clamp your legs under the designated fixture. Your back should not arch too much. Look forward and tense your abs. Then begin the exercise.
Exhale and roll your upper body forward in a controlled manner. Bring your chest toward your pelvis. Important: Do not pull with your arms or push with your legs. Roll forward until you feel a significant tension in your abs, and pause briefly in this position. Then inhale and slowly return to the starting position in a controlled manner. Stop just before setting the weight down to maintain tension in the abs.
Common Mistakes
Basically, the crunch machine is very easy to use. However, there are two things you should pay special attention to:
- Too much weight: Don’t let your ego decide, but your mind. The movement should be controlled from the abdominal muscles and not with momentum from the arms and shoulders. Using too much weight takes some of the work away from the abs, reducing the training effect.
- Leaning back too far: More movement doesn’t automatically mean more here. Lean back only as far as needed to keep the abs under tension. If you fall too far back and arch your back, you unnecessarily shift the load to the lower back.
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It’s Not Just About Looks
Yes, for many, the appearance of a six-pack is motivation enough. But trained abs are useful beyond just looks. They stabilize the entire torso, supporting a healthy posture and the spine. In fact, they also play an important role in coordination and balance, as the torso connects the upper and lower body. Additionally, well-trained core muscles support the pelvic floor and can relieve it, especially during heavy loads like squats or deadlifts.
Also interesting: Ab training only in summer? Here’s why it’s important in winter too
More Effective Than the Regular Crunch?
Crunch machine or classic crunches on the floor? It’s hard to say which is more effective. Both train the abs and have their own advantages. In the end, it also depends on which exercise suits you better.
The advantage of the crunch machine is that the resistance can be specifically adjusted and increased as strength improves. This makes progress in ab training easier to measure.
Classic crunches, on the other hand, don’t require equipment and can also be effective. However, if they become too easy, additional resistance or a higher number of repetitions is needed.