Health and fitness: A case against crunches
November 27, 2013
The core can be a controversial and mysterious topic. Recent research suggests that crunches and situps may place undue stress on the spine that might actually be dangerous. However, many coaches and trainers say that the benefits outweigh the potential risks. But are crunches and situps really the best core exercises to target the core?
One study published in the Journal of Orthopedic & Sports Physical Therapy examined which exercises targeted the core the best. The researchers tested seven different commercial abdominal machines and two classic bodyweight abdominal exercises: the crunch and the bent-knee situp. Most of the exercise machines were similar to the crunch and situp motion, however, two of the machines forced the abs to produce a different motion similar to a plank where the core is actually not moving at all. So how can to work a muscle without moving it? The plank and ab rollout exercise do just that. The ab rollout exercise uses the classic ab wheel or Swiss ball where you start in a plank position and "rollout" without bending the spine, this forces the core to resist gravity and uses your own body weight. Think about a game of tug-of-war. Even though no one is moving, both teams are still working very hard.
Based on the results of this study, "The Ab Slide and Torso Track exercises produced the highest activation of the abdominal and upper extremity muscles while minimizing low back and hip flexion activity." These are the same machines that didn't involve a crunch or situp motion, but instead a plank or ab rollout-type motion was used.
In a separate study published in 2010, the crunch and bent-knee situp were tested against several Swiss ball exercises, including the Swiss ball rollout, the same motion as the two core machines which produced the highest core activation in the previous study. This study once again found out the crunch and the situp didn't hit the core as hard as the rollout movement; "The roll-out and pike were the most effective exercises in activating upper and lower rectus abdominis, external and internal obliques, and latissimus dorsi muscles, while minimizing lumbar paraspinals and rectus femoris activity." What this saying is that these exercises made the core workout harder and took pressure off the low back and groin muscles. With an epidemic in American of low back pain, this once again, shows evidence in favor of switching situps with rollouts and planks.
In other words, abdominal rollouts may not only be safer on the spine, but more effective at activating the core than crunches or situps. Planks and rollout are not only safer, but according to these and several other studies the superior exercise for most people. This does not mean you have to throw out crunches completely. With almost every exercise, there is a time and place for everything, but, like the authors point out, "Because the Ab Slide and Torso Track exercises produced the greatest activation of both abdominal and upper extremity musculature, these exercises may be beneficial for individuals with limited … The greater relative intensity and number of muscles used during the Ab Slide and Torso Track exercises implies that these exercises may also achieve a greater energy expenditure compared to the other exercises." The more calories you burn, the faster you will be able to see your abs.
Although the Ab Slide and Toro Track are infomercial products, don't let that mislead you. Hust think of them as rollouts using the Swiss ball or planks, exercises that don't flex the spine and force the core to stabilize and work really hard. Once again, I don't think you are going to blow your back out with a few sets of situps, but if rollouts work the core more and without the potential danger of putting the spine in a dangerous position, why not switch them up?
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— Kyler Crouse, BS, CSCS, FMS is a personal trainer and strength coach that trains at Sierra Athletic Club and a training center instructor at Barton Memorial Hospital. Kyler specializes in performance enhancement and post rehabilitation. Visit http://www.KCstrength.com for more information.