Abdominal exercise

Abdominal exercises are those that affect the abdominal muscles (colloquially known as the stomach muscles or "abs").

Effects

Abdominal exercises are useful for building the abdominal muscles. This is useful for improving performance with certain sports, back pain, and for withstanding abdominal impacts (e.g., taking punches). According to a 2011 study, abdominal muscle exercises are known to increase the strength and endurance of the abdominal muscles.^[1]

It has been highly disputed whether or not abdominal exercises have any reducing effect on abdominal fat. The aforementioned 2011 study found that abdominal exercise does not reduce abdominal fat; to achieve that, a deficit in energy expenditure and caloric intake must be created—abdominal exercises alone are not enough to reduce abdominal fat and the girth of the abdomen.^[1] Early results from a 2006 study found that walking exercise (not abdominal exercise specifically) reduced the size of subcutaneous abdominal fat cells; cell size predicts type 2 diabetes according to a lead author. Moderate exercise reduced cell size by about 18% in 45 obese women over a 20-week period; diet alone did not appear to affect cell size.^[2]

Functions of abdominal muscles

Abdominal muscles have many important functions, including in breathing, coughing, and sneezing, and maintaining posture and speech in a number of species.^[3] The anterior abdominal wall is made up of four muscles—the rectus abdominis muscle, the internal and external obliques, and the transversus abdominis."The two internal muscles, the internal oblique and the transverse abdominis, respond more to increases in chemical or volume-related drive than the two external muscles, the rectus abdominis and external oblique; the basis for this differential sensitivity is unknown".^[3]

Core training

Not only can one-sided preference for abdominal muscles (lack of exercise focused on other core muscles) result in creating muscle imbalances, but the effectiveness of exercise is also far from what could be achieved with a balanced workout planning. Core training frequently utilizes balance exercises. These are characterized by unstable position that requires involvement of a wide range of muscles which help balance oscillation of the centre of gravity. We can balance both in static positions and while performing dynamic movements.

The goal of core training is definitely not to develop muscle hypertrophy but to improve functional predispositions of physical activity. This particularly involves improving intra- and intermuscular coordination or synchronization of participating muscles.

Involvement of the core means more than just compressing abdominal muscles when in crouching or seated position. The role of the core muscles is to stabilize the spine. Resisting expansion or rotation is as important as the ability to execute movement.

Types of abdominal exercises and effectiveness

The abdominal muscles can be worked out by practicing disciplines of general body strength such as Pilates, yoga, T'ai chi, and jogging among others. There are also specific routines to target each of these muscles.

Momentaneous activity

One way to estimate the effectiveness of any abdominal exercise is in measuring the momentaneous activity by electromyography (EMG), with the activity generally being compared to that of the traditional crunch. However, an exercise of lower activity performed during a longer time can give at least as much exercise as a high-activity exercise, with the main difference being that a prolonged duration results more in aerobic exercise than strength training.

The following tables rank abdominal exercises from highest to lowest in terms of activity as determined by the EMG measures:^[4]

Activity in rectus abdominis exercise mean activity^1 Bicycle crunch 248% Captain's chair 212% Exercise ball 139% Vertical leg crunch 129% Torso track 127% Long arm crunch 119% Reverse crunch 109% Crunch with heel push 107% Ab roller 105% Hover 100% Traditional crunch 100% Exercise tubing pull 92% Ab rocker 21%

Activity in obliques exercise mean activity^1 Captain's chair 310% Bicycle crunch 290% Reverse crunch 240% Hover 230% Vertical leg crunch 216% Exercise ball 147% Torso track 145% Crunch with heel push 126% Long arm crunch 126% Ab roller 101% Traditional crunch 100% Exercise tubing pull 77% Ab rocker 74%

¹Compared to traditional crunch (100%)

Bicycle crunch

The bicycle targets the rectus abdominals and the obliques. Also, the rectus abdominals can be worked out with the basic crunch, the vertical crunch, the reverse crunch, and the full vertical crunch, and when at a low enough body fat percentage (10-12% for males, 15-18% for females) the individual parts of the muscle become visible; many refer to this visible separation as a six pack. By exercising the internal and external obliques the stomach can be flattened while the waist line can be reduced.^[5] The long arm crunch, in which arms are straightened behind you, adds a longer level to the move and emphasizes the upper part of the abs. The plank exercise not only strengthens the abs but also the back and stabilizes the muscles.^[6]

Gadgets

Abdominal exercises can also be performed with the help of some machines and the captain's chair is one of the most popular machines used in gyms and health clubs. Other machines are the Ab Roller, the Ab Rocket Twister, the Chin-up bar in conjunction with Ab Straps and the Torso Track. The exercise ball is also a tool that helps strengthen the abs. It may be more effective than the crunches on the floor because the abs do more work as the legs are not involved in the exercise.^[7] With respect to the Ab-Slide, the study performed by Bird et al. showed greater muscle activation in the upper rectus abdominis, lower rectus abdominis, and external oblique when compared to the standard abdominal crunch. The Ab-Slide has proven to be an effective tool in strengthening the abdominal muscles from a concentric muscle action perspective. However, this research does not support replacing the traditional crunch exercise with the Ab-Slide gadget due to the lack of proven effectiveness in the eccentric loading of the abdominal muscles and the greater postural control.^[8][9] Potentially the most effective equipment for abdominal strengthening are those that offer the least stability. Examples include the CoreFitnessRoller, bodyweight suspension training such as TRX and stability balls with or without the Halo.

Safety of abdominal exercises

Abdominal exercises also put some degree of compressive force on the lumbar spine, putting unwanted stress on the lower back. In addition, exaggerated abdominal exercise can cause respiratory problems.^[10] A study of twelve exercises concluded that no single exercise covered all abdominal muscles with high intensity and low compression.^[11]

High challenge-to-compression ratio Crunch with feet anchored Crunch with feet free Bicycle crunch Hanging straight leg raise	Low compression, lower challenge Crunch with feet anchored Crunch with feet free
High challenge, higher compression Straight-leg sit-up Bent-leg sit-up	Low challenge-to-compression ratio (not recommended!) Supine straight-leg raise Supine bent-leg raise Hanging bent-leg raise Static cross-knee crunch

The benefit of focused training on the "deep core" muscles such as the transversus abdominis has been disputed, with some experts advocating a more comprehensive training regimen.^[12]

See also

• Abdomenizer
• Abdominal fat
• Chin-up bar
• Core (anatomy)
• Crunches
• Pilates
• Roman chair
• Situps
• Spot reduction

References

1. Vispute, Sachin S; Smith, John D; Lecheminant, James D; Hurley, Kimberly S (2011). "The Effect of Abdominal Exercise on Abdominal Fat". Journal of Strength and Conditioning Research 25 (9): 2559–64. doi:10.1519/JSC.0b013e3181fb4a46. PMID 21804427.
2. You, T; Murphy, K M; Lyles, M F; Demons, J L; Lenchik, L; Nicklas, B J (2006). "Addition of aerobic exercise to dietary weight loss preferentially reduces abdominal adipocyte size". International Journal of Obesity 30 (8): 1211–6. doi:10.1038/sj.ijo.0803245. PMID 16446745. Lay summary – ScienceDaily (August 7, 2006).
3. Iscoe, S (1998). "Control of abdominal muscles". Progress in Neurobiology 56 (4): 433–506. doi:10.1016/S0301-0082(98)00046-X. PMID 9775401.
4. Anders, Mark (2001). "New Study Puts the Crunch on Ineffective Ab Exercises" (PDF). ACE fitnessmatters: 9–11. Archived from the original (PDF) on August 18, 2007.
5. "Abdominal Muscle Anatomy". Archived from the original on 27 July 2010. Retrieved 2010-07-13.
6. "Top 10 Most Effective Ab Exercises". Archived from the original on 11 August 2010. Retrieved 2010-07-13.
7. "Top 10 Most Effective Ab Exercises". Archived from the original on 11 August 2010. Retrieved 2010-07-13.
8. Michael Bird, Kate M. Fletcher, and Alex J. Koch. Electromyographic Comarison of the Ab-Slide and Crunch Exercises. Journal of Strength and Conditioning Research. 20(2), 436–440, 2006.
9. "Top 10 Most Effective Ab Exercises". Archived from the original on 11 August 2010. Retrieved 2010-07-13.
10. Verges, Samuel; Lenherr, Oliver; Haner, Andrea C.; Schulz, Christian; Spengler, Christina M. (2006). "Increased fatigue resistance of respiratory muscles during exercise after respiratory muscle endurance training". American Journal of Physiology. Regulatory, Integrative and Comparative Physiology 292 (3): R1246–53. doi:10.1152/ajpregu.00409.2006. PMID 17068160. INIST:18626671.
11. CT Axler; SM McGill (1997). "Low back loads over a variety of abdominal exercises: Searching for the safest abdominal challenge". Medicine & Science in Sports & Exercise 29 (6): 804–810. doi:10.1097/00005768-199706000-00011. PMID 9219209.
12. Reynolds, Gretchen (2009-06-17). "Is Your Ab Workout Hurting Your Back?". New York Times. Archived from the original on 20 June 2009. Retrieved 2009-06-19.