This is probably one of the hardest exercises to work your core as it focuses in on both the top and bottom portions of your abdominals. With the ab wheel on the floor, get on your hands and knees and grab the handles of the ab wheel and extend straight out so that core is parallel to the floor and then return to the beginning position. Like most bodyweight exercises, you can this one slightly easier or harder by pulling your knees off the floor or keeping them on the floor. To work the obliques, you can curve the path of the wheel slightly to the right or left and target those sides.
Ab wheels come in different sizes. The one from the video below is a bit larger than many of the smaller ab wheels you'll typically see in the gym, but they all work the same way.
I´m not a big fan of infomercial gadgets, especially the really fancy ones, and I really don't recommend them. The only one I really recommend is the ab wheel. You can pick one up at Walmart for under 20 bucks, and it works your abs hard without crunches.
But do other ab gadgets hold up?
Researchers (from the Mayo Clinic, of all places) tested the "Ab-Slide" device and compared it to the ab crunch, the supine double leg thrust (seated knee tuck-in), and side plank.
Reference:
J Strength Cond Res. 2008 Nov;22(6):1939-46.
For those of you science junkies like myself here is the abstract
AB Youdas, JW, Guck, BR, Hebrink, RC, Rugotzke, JD, Madson, TJ, and Hollman, JH. An electromyographic analysis of the Ab-Slide exercise, abdominal crunch, supine double leg thrust, and side bridge in healthy young adults: implications for rehabilitation professionals. J Strength Cond Res 22(6): 1939-1946, 2008-The purpose of this study was to examine the effectiveness of a commercial abdominal machine (Ab-Slide) and three common abdominal strengthening exercises (abdominal crunch, supine double leg thrust, and side bridge) on activating abdominal and minimizing extraneous (nonabdominal) musculature-namely, the rectus femoris muscle. We recruited 10 males and 12 females whose mean (+/- SD) percent body fat was 10.7 +/- 4 and 20.7% +/- 3.2%, respectively. Electromyographic (EMG) data were recorded using surface electrodes for the rectus abdominis, external oblique, internal oblique, and rectus femoris. We recorded peak EMG activity for each muscle during each of the four exercises and normalized the EMG values by maximum muscle contractions (% MVIC). A two-factor repeated-measures analysis of variance assessed differences in normalized EMG activity among the different exercise variations (p < 0.05). Post hoc analyses were performed using the Bonferroni-adjusted [alpha] to assess between-exercise pair comparisons (p < 0.002). Gender did not affect performance; hence, data were collapsed across gender. We found a muscle x exercise interaction (F9,189 = 5.2, p < 0.001). Post hoc analyses revealed six pairwise differences. The Ab-Slide elicited the greatest EMG activity for the abdominal muscles and the least for the rectus femoris. The supine double leg thrust could be a problem for patients with low-back pathology due to high rectus femoris muscle activity. (C) 2008 National Strength and Conditioning Association.
Ten young men and twelve young women did all the exercises.
Tests showed that the Ab-Slide, a contraption fairly similar to the Ab Wheel, worked the abs the hardest.
On the other hand, the seated knee tuck-in required a lot of hip flexion, and the doctors believed it could cause BACK PROBLEMS in people prone to low back injury.
Personally, I'm going to stick with the Ab Wheel, but as usual, I'm going to keep crunches out of my program, and add the Seated Knee Tuck-in to my list of ab exercises to avoid.
Stick to the exercises in the Turbulence Training for Abs program.
Click here for more ab exercises and workouts:
=> http://tinyurl.com/ykojy5z
Train hard and eat healthy
Craig Ballantyne, CSCS, MS
Turbulence Training for Abs
modified by JP
PS – Just say NO to crunches.
Not only are crunches hard on your low back, they are also useless
for helping you get a flat stomach.
Instead, stick to interval training, the ab exercises in Turbulence
Training for Abs, and Isabel De Los Rios’ advanced ab nutrition
guidelines if you want to transform your body.