Core Strength

The argument of how to strengthen one's core or how to get abs quickly, is nine times out of ten, the first thing people will ask when beginning a training regimen. In order to properly train someone's core, it's important to break down what that actually means. According to Floyd, we have our inner and outer core. The inner core consists of the diaphragm, transversus abdominis, lumbar multifidus, and the muscles of the pelvic floor. It is important to activate the inner core first, in order to stabilize the spine and trunk. The outer core consists of the rectus abdominis, external obliques, internal obliques, and erector spinae. These muscles help produce force through intra-abdominal pressure and contractile forces.  (Floyd, 2021, pg 360 & Hibbs et al. 2008). 

In an article on optimizing performance by improving core stability and core strength, they reference Lehman, who claims that the transverse abdominis, rectus abdominis, external obliques, internal obliques, erector spinae, quadratus lumborum and latissimus dorsi are very important to look at when analyzing ones core because they have the ability to produce flexion, lateral flexion and rotational movements, which can help control external forces. With that said, it made me think about what abdominal exercise can potentially activate all or most of these muscles, in order to produce the most effective abdominal exercise. Many would argue that because these muscles produce flexion, sit-ups would be the ideal exercise. However, a study by Sports Health proves differently. (Hibbs et al. 2008)

In this study by Sports Health, they took 18 men and women ages 23-45, and had them perform a number of abdominal exercises, while placing electrodes on their upper and lower rectus abdominis, external and internal obliques, rectus femoris, latissimus dorsi, and lumbar paraspinals. They compared the typical crunch and bent knee sit-up with different variations of prone position exercises with and without a stability ball (Swiss ball). Their findings demonstrated that prone position exercises are very effective for core musculature recruitment. Prone position exercises with the stability ball (holding a plank with legs on the stability ball) resulted in similar upper and lower rectus abdominis, internal oblique and lumbar paraspinal activity. Furthermore, there were significant increases in activity of the external oblique, latissimus dorsi, rectus femoris when compared to a crunch. The prone position on the ball with the left hip extended generated 50% more rectus femoris activity compared with the bent-knee-sit-up (Escamilla, 2016). 

When finding the most effective and efficient abdominal exercise for a patient or client, I would have them perform different variations of plank on a stability ball, based on current fitness and stability level. Although the article did not mention the transverse abdominis, this is one of the muscles activated during a plank. As mentioned earlier, it is important to activate the inner core muscles, including the transverse abdominis first to stabilize the spine and trunk. When instructing someone to perform a plank on a stability ball, I would have them start by holding the isometric prone position and then continue to progress with single leg hip extension, while remaining in a plank on the ball. This will not only strengthen the abdominals but also stabilize the pelvis and spine due to isometric abdominal and oblique muscle actions. From there progressions can be made by bringing the body into a pike position and back down to a plank.  If you're dealing with a less active or older population, planking without the stability ball may be necessary at first. However, performing a plank on their elbows and toes can still be more beneficial than a sit-up or crunch for these populations, especially when dealing with osteoporosis and disc pathologies. (Escamilla, 2016)

Floyd, R. T. (2021). Manual of Structural Kinesiology. 21st addition. McGraw-Hill Education. 

Escamilla, R. F., Lewis, C., Pecson, A., Imamura, R., & Andrews, J. R. (2016). Muscle Activation Among Supine, Prone, and Side Position Exercises With and Without a Swiss Ball. Sports health, 8(4), 372–379. https://doi.org/10.1177/1941738116653931

Hibbs, A. E., Thompson, K. G., French, D., Wrigley, A., & Spears, I. (2008). Optimizing performance by improving core stability and core strength. Sports medicine (Auckland, N.Z.), 38(12), 995–1008. https://doi.org/10.2165/00007256-200838120-00004