Selecting the Appropriate ‘Core’ or Abdominal Exercise

https://www.youtube.com/watch?v=WMvyrrqolJw

External Oblique

The biggest and thickest abdominal muscle is this one. As it wraps around the trunk from the bottom eight ribs, it creates the abdominal aponeurosis (fascia), which connects to the linea alba. When the external oblique is contracted in unison, it causes the trunk to flex in one way, whereas unilateral contraction causes the same side’s trunk to flex in the other direction (different to the internal oblique).

Internally oblique

The transverse abdominis aponeurosis and the iliac crest (hip) are the sources of the internal oblique (fascia). It connects to the cartilage of the bottom four ribs in the front of the chest at a right angle to the external oblique. Bilateral contractions result in trunk flexion and abdominal compression for functions like breathing, while one-sided contractions produce rotation and/or lateral flexion to the same side.

Transverse abdominis

Of the three layers, this muscle creates the deepest layer. The abdominal muscle that is most horizontally positioned is this one. This muscle arises from the hip, the iliac crest, and the transverse processes of the spine in the back. It curves around the trunk and joins the anterior abdominal wall aponeurosis. When both sides contract at the same time or when a unilateral contraction occurs, the transverse abdominis causes trunk rotation.

Rectus abdominis muscles

Rectus is the 6-pack muscle that all the men in the gym spend their whole lives trying to sculpt. The rectus muscle was first developed to support the pubic symphysis and crest. It is attached to the xiphoid process and cartilage of ribs 5 to 7. The ab crunch action is produced by it (trunk flexion). The linea alba divides the muscle’s left and right sides as it travels vertically.

This site also mentions the Psoas Major/Minor, Quadratus Lumborum, and Erector Spinae, which are not abdominal muscles.

Describe EMG

When a muscle contracts, an electrical signal is released. The science of monitoring these electrical impulses coming from the muscles is called electromyography, or EMG. More muscle fibers are recruited when a muscle creates force, which results in an increase in the electrical activity of the contracting muscles. When this is measured, we see that the signal’s amplitude has increased (see picture below). Specialized surface electrodes placed on the skin over the muscles detect this electrical output (1). We can identify which workouts produce greater electrical activity in each muscle and, therefore, which muscle is more selectively recruited or targeted when applied to several muscles during exercise.

Particular exercise should I do to work which muscle?

Let’s now pair up this limited, carefully chosen collection of exercises with the muscle or muscles that they have been demonstrated via EMG research to stimulate most strongly.

Bend your knee and curl it, then bend your knee and sit up.

Dynamic side bridges and isometric side bridges are internal obliques.

External Obliques: side bridges and sit-ups (both types)

Sit-ups and side bridges for the transverse abs

Straight leg lift with Psoas Major/Minor

Straight leg raise and straight leg sit-up for the Rectus Femoris

Dynamic and isometric side bridges for the erector spine

Quadratus Lumborum: side bridge in isometric

Please be aware that there are many techniques to target your abdominal muscles, and the exercises I’ve included above are only a small selection for which I was able to find scientific support.