August 19, 2025, 4:22 pm | Read time: 5 minutes
When it comes to choosing the right exercise for abdominal training, sit-ups and planks are particularly popular. While sit-ups are often seen as a classic exercise for strengthening the abdominal muscles, planks have emerged in recent years and proven to be superior. FITBOOK trainer Alina Bock explains why planks should be preferred over sit-ups when it comes to strengthening the core and specifically the abdominal muscles.
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Which Muscles Are Trained
Sit-ups have long been considered the standard exercise for training the abdominal muscles. However, it has now been shown that the forearm plank is considered superior due to its strengthening of the entire core muscles and promotion of coordination and stability. Like the forearm plank, sit-ups train the abdominal muscles. Nevertheless, the two exercises differ in the extent of muscle activation.
Muscle Activation – Sit-ups
Sit-ups primarily train the straight and thus visible abdominal muscles (rectus abdominis). Additionally, the oblique (obliquus abdominis) and partially the deep (transversus abdominis) muscles are activated and strengthened. If the hands do not stabilize the cervical spine, the neck muscles take on this task and strengthen the spine in the process.
Muscle Activation – Plank
In addition to the straight, oblique, and deep abdominal muscles, the plank also strengthens the muscles around the spine, the large back muscle, the shoulder muscles, the lower back muscles, and their interaction. With proper tension, the entire core is effectively strengthened. It is essential to ensure that the navel is pulled firmly inward and the pelvis is tilted toward the floor during execution. This way, the aforementioned muscles can be activated.
Advantages of Planks Over Sit-ups
Planks are more effective than sit-ups in several respects. The following section explains which factors these are.
Full-Body Activation
As previously mentioned, sit-ups primarily train the straight and thus visible abdominal muscles, while planks promote the entire core muscles and their cooperation. By activating the deep muscles, the entire abdominal muscles, the muscles around the spine, as well as the back and shoulder muscles, are activated and strengthened. Thus, the plank is an exercise for the entire body, while sit-ups only strengthen the visible abdominal muscles.
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Involvement of the Pelvic Floor
In addition to the abdominal, back, and shoulder muscles, an important part of the body consisting of several muscles, the pelvic floor, is also activated during the activation of the deep muscles. With proper tension, it can be effectively trained. Thus, the plank is an effective exercise for preventing pelvic floor problems or restoring healthy pelvic floor function.
Unlike sit-ups, which are not suitable after a certain month of pregnancy due to the risk of the straight abdominal muscles separating, planks can be performed throughout pregnancy and even after childbirth–they also promote the restoration of pelvic floor function in a healthy way.
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Improved Stability and Coordination
The activation of numerous muscles not only strengthens their power but also improves their interaction. Regularly performing the exercise enhances coordination and leads to noticeably better balance. Improved coordination and balance further prevent back problems or, in the case of existing issues, provide relief. Thus, the forearm plank is a prioritized exercise by trainers when it comes to training a client’s back and core muscles after a herniated disc.
Lower Risk of Injury
The plank is an isometric exercise where the joints remain unmoved. The muscles work by holding the position for an extended period.
Sit-ups, among other things, move the spine. If performed incorrectly over a long period, this can lead to injuries–for example, if the cervical spine is hyperextended and held in an unfavorable position during execution.
Variation Options
Both exercises offer variations to increase intensity. For example, sit-ups can be performed negatively or with additional weight, increasing the load. The plank, however, is much more versatile: targeted variations can not only adjust the intensity but also involve a larger number of muscle groups. An example is rowing during the held plank position–this effectively trains the upper back muscles, core muscles, and their interaction.
Other variations derived from the plank include:
- Plank with rowing motion
- Plank Up and Downs
- Plank Knee to Elbow
- Plank with leg lift
- High Plank
- High Plank with shoulder tap
- Reverse Plank
- Plank Jacks
Conclusion
When comparing sit-ups and planks in terms of muscle activation, promotion of coordination and stability, and variation options, the plank proves to be superior. Sit-ups are not ineffective–however, the forearm plank covers more muscle groups and leads to an upright posture by targeting the deep muscles. Thus, it helps alleviate back pain and prevent back issues.
The plank is suitable for almost everyone–such as pregnant women, people with back conditions, or pelvic floor issues–and can generally be performed without concern. However, it is crucial to always work with the correct body tension to make the exercise as effective as possible.