Core Exercises: Sit-ups as Targeted Approach to Decreased Abdominal Adiposity?

The sit-up exercise, through many years, has been chosen by many as a “spot reducing” exercise for the mid-section. When you walk into fitness facilities, you would see dozens of people on the floor, crunching away, thinking that they would get nice, tight abs by doing repetition-after-repetitions of the sit-up exercise. However, many research suggests that energy balance is still the key to weight loss and decreasing risk factors for obesity, (4).

Direct training of the mid-section/ abdominals has been shown to have no significant effect on measures of abdominal fat (measured by DXA, waist circumference, and skinfold); however, the same study shows increase in abdominal musculature endurance after a 6-week training of direct abdominal exercises, (5). Different sit-up variations also did not appear to activate significant level of abdominal musculature, (2).

LumbarFlexion-1
Lumbar Flexion can lead to disc herniation (bulge) over time! As repeated loading occurs, tissue tolerance slowly decrease, increasing risk for injury.

Image-2-repeated-load

 

 

Nevertheless, if muscle hypertrophy is the lone goal, the abdominal sit-up exercise has been shown to have a higher rectus abdominus (RA) activation than its safer counter-part, the curl-up, (1). However, if overall health and longevity is the main premise of an exercise routine, the abdominal sit up exercise has been shown to cause excessive lumbar flexion and extreme intervertebral shear forces, which in the long run can cause a barrage of lower back problems, such as lumbar disc herniation (2).

An article published in the International Sport Science Association investigating U.S Military personnel (where this exercise is used as a fitness assessment protocol) suggests that the abdominal sit-up exercise work against the natural curvature of the spine, which can, overtime, lead to chronic low back injuries.  A statistic survey reports that 56% of the soldier’s injuries relating to “old fitness test” has been linked to this said exercise. (3)

  1. Anderson, EA, Nilsson, J., Ma, Z., Thoestensson, A.(1997). Abdominal and hip flexor muscle activation during various training exercises. European Journal of Applied Physiology and Occupational Physioogy. 75(2); 115-123. DOI: 10.1007/s004210050135
  2. Axler, C.T., McGill, S.M., (1997). Low back loads over a variety of abdominal exercises: searching for the safest abdominal challenge. Medical and Science in Sports and Exercise, 29(6): 804-811.
  3. Baker, C. (2016). Are sit ups bad for you? the U.S. military seems to think so… International Sport Sscience Association. Retrieved from: https://www.issaonline.edu/blog/index.cfm/2016/are-sit-ups-bad-for-you-the-us-military-seems-to-think-so
  4. Luke, A., Cooper, R.S., (2013). Physical activity does not influence obesity risk: time to clarify the public health message. International Journal of Epidemiology, 42 (6): 1831-1836. doi: 10.1093/ije/dyt159
  5. Vispute, SS., Smith, J.D., LeCheminant, J.D., Hurley, K.S., (2011). The effect of abdominal exercise on abdominal fat. Journal of Strength and Conditioning Research, 25(9), 2559-2564.

 

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