By Michael J. Rudolph, Ph.D.
Having a well-defined midsection with impressive abdominal muscles is the goal for many individuals who work out. Unfortunately, I still see so many people sitting in the matted area of my gym, busting their tails doing sit-up after sit-up, with the expectation of developing a leaner waistline with ripped abs. Sit-ups have also been utilized traditionally to develop the strength and stability of the other core muscles. Since the core is central to the body, a stronger core is able to transfer force more efficiently throughout the body during exercise, supporting greater strength production and lean muscle. Furthermore, the core’s muscles are activated while performing many different athletic movements— meaning a stronger core also enhances performance on the athletic field, representing one more reason to want a stronger core.
While the sit-up may intuitively seem like the best way to cultivate shredded abs and greater core strength, there are better training modalities that more effectively activate all of the core muscles. The other training modalities ultimately result in better development of the abdominal muscles and that sought-after six-pack, as well as core strength, for better overall body strength and athletic performance.
Another advantage of a stronger core is a decreased risk of injury. This evidently occurs because a stronger core has a greater capacity to stabilize the joints and soft tissue within the core, while also promoting better movement patterns that altogether reduce the likelihood of injury. Yet, in addition to the relative inability of the sit-up to improve the core muscles, performing sit-ups may actually damage the spine. The potential injury to the spine occurs, in part, from the activation of the hip flexors (a muscle group that runs from the top of the thigh bone to the vertebrae in the lower back) during the initial phase of the sit-up, putting a substantial amount of compressive force on the spinal disks within the compressed region of the spine. The greater compressive forces on the disk increase the risk for disk herniation that may cause the disk to pinch a nearby nerve, producing considerable pain. Another injury concern associated with sit-ups use is the repeated bending of the spine that occurs during the sit-up that could deteriorate the spine over time, causing chronic pain and injury.
As a result of the many shortcomings associated with the sit-up, you should probably rethink your entire approach to core training— incorporating some of the more effective, and relatively safer, exercises that will be mentioned within this article. The exercises I describe will generate superior core muscle activation, providing a greater training stimulus that generates a much stronger and more ripped core.
Better Abdominal Exercises
Two alternative core exercises that were shown to trigger significantly greater activation of the abdominal and oblique muscles than the sit-up, and therefore should be done in lieu of the ineffective sit-up, are the power wheel roll-out and the hanging knee-up (or hanging knee-raise). The power wheel roll-out starts with your knees on the floor and your hands holding the power wheel on the floor directly in front of your body, very close to the knees. From this position, the subject straightens out the body by rolling the wheel forward in a straight line, while maintaining a straight spine and pelvis throughout the entire movement. When full extension is reached, the subject simply reverses direction back toward the body until the wheel is in its original position, immediately in front of the knees.
The hanging knee-up exercise begins with the body hanging in a vertical position with the trunk, hips and knees in full extension. From this position, the subject simply flexes the hips slowly, pulling the knees up while keeping the legs together, resulting in about 125 degrees of hip and knee flexion. At the top position, pause for a second and then slowly lower your knees back to the starting position.
One study showed that the power wheel roll-out and hanging knee-up were superior to the sit-up. Researchers attached electrodes to the core muscles of 21 subjects to measure muscular activity of the core, while performing 12 different abdominal muscle exercises including the sit-up, power wheel roll-out and the hanging knee-up. The data showed that the power wheel roll-out most strongly activated the upper and lower abdominal muscles, while the hanging knee-up movement induced the highest muscular activity within the internal and external oblique muscles. On the other hand, the sit-up performed rather poorly— activating the abdominal muscles to only one-half the level of the power wheel roll-out, and the oblique muscles to one-half the activity triggered by the hanging knee-ups. Taken together, these results show that the sit-up is a poor choice for overall abdominal training, while the power wheel roll-out should be utilized, especially if you are focusing on abdominal development— and the hanging knee-up should be employed to more precisely target the oblique muscles.
Deadlifts Activate the Entire Core
While the deadlift is customarily known for its unparalleled capacity to pack on muscle mass and strength, it is also very good at building core strength by directly activating all of the major muscle groups responsible for core strength. In fact, the deadlift actually enhances core strength and development more effectively than many of the popular core-training techniques used today, including the sit-up.
The ability of the deadlift to potently activate the entire core was demonstrated in a study by Hamlyn et al., which investigated the level of activation of various core muscles while performing the deadlift and two well-known core-training exercises, the superman and side-bridge. In this study, 16 subjects performed either deadlifts with 80 percent of their one-repetition maximum (1RM), the superman or the side-bridge, while having their core muscle activity measured. The results showed that deadlifts activated certain core muscles 70 percent more than either the superman or side-bridge exercises. Since the superman and side-bridge exercises are better at activating core muscles than the sit-up, the deadlift is also more effective at triggering core muscle function than the sit-up. As a result, the deadlift is an often overlooked, yet apparently essential component of any training regimen for core development, whereas the use of the sit-up seems to be relatively ineffective at hitting the core muscles.
In conclusion, while many still utilize the sit-up to improve abdominal development and core muscle performance, the scientific evidence clearly shows that alternate training methods such as the power wheel roll-out and hanging knee-raise, along with the deadlift, generate superior activation of the primary muscle groups within the core. The greater ability of these different training modalities to activate core muscle groups promotes a superior training adaptation that more potently enhances core development and strength, ultimately leading to improved performance in the weight room and that highly sought-after six-pack.
1. Kibler WB, Press J and Sciascia A. The role of core stability in athletic function. Sports Med 2006;36, 189-198.
2. McGill SM. Low back disorders: evidence based prevention and rehabilitation. Human Kinetics Publishers 2007.
3. Callaghan JP and McGill S.M. Intervertebral disk herniation: studies on a porcine model exposed to highly repetitive flexion/extension motion with compressive force. Clin Biomech 2001 (Bristol, Avon);16, 28-37.
4. Tampier C, Drake JD, et al. Progressive disc herniation: an investigation of the mechanism using radiologic, histochemical, and microscopic dissection techniques on a porcine model. Spine 2007 (Phila Pa 1976);32, 2869-2874.
5. Escamilla RF, Babb E, et al. Electromyographic analysis of traditional and nontraditional abdominal exercises: implications for rehabilitation and training. Phys Ther 2006;86, 656-671.
6. Hamlyn N, Behm DG and Young W.B. Trunk muscle activation during dynamic weight-training exercises and isometric instability activities. J Strength Cond Res 2007;21, 1108-1112.