This advanced exercise works your whole abs. Since the exercise is weighted and requires balance, start easy to acclimate yourself.
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In this exercise analysis (Quicktime, 13.8 MB; Vox, no download), Nancy Arnold and I (Bud) present a dumbbell jackknife, yet another in our abs series. We find variety in the abs exercises helps reduce boredom, and the challenge can be just plain fun. As you might imagine looking at the strip on the right, dumbbell jackknifes work all of the abdominals. Since the exercise is weighted and requires balance on a bench, you should consider it an advanced exercise. Start easy and the movement down before trying to go up in weight.
The exercise requires a dumbbell and a bench. Nancy, a strong woman, used a 20 lb. dumbbell for 15 reps. I used a 40 lb. dumbbell for 15 reps. As illustrated in the strip of photos at the left, the bench should be short enough that, with your head at one end, your knees can extend beyond the other with the ability to bend at a 90 degree angle.
As we show in the video, you get into position by lying back on the bench holding the dumbbell on your chest. You then get in position by carefully placing the dumbbell behind your head as we illustrate in Photos 1 & 3 on the left. Much like BOSU jackknifes, you perform the exercise by simultaneously raising your upper torso and knees. In raising your upper torso, you bring the dumbbell from behind your head and touch it to your knees. You then return to the start position by relaxing your abs in a controlled manner and bringing the dumbbell back behind your head. In the relaxed position, you should maintain tension on your abs by keeping your feet slightly off the floor.
Individual characteristics contribute a lot to how you will perform the exercise. As a man, I have a shorter torso and tighter joints than Nancy, a woman. So, in the up position (Photo 2), you will see that my knees are bent and that I don't have quite the same torso bend as Nancy (Photo 4). Due to her length, Nancy's feet actually touch the floor in the down position (Photo 3).
Additional Links
- Jackknifes are a typical component in weight training programs.
Comments (2)
also while performing this particular exercise amongst most abdominal exercise be sure to maintain correct posture with chin tucked into chest as this will minimise next flexors activating therefore minimising risk of long term headaches, upper-cross-syndrome etc...
Posted by Brett | November 2, 2006 8:40 PM
Posted on November 2, 2006 20:40
Thanks for the additional tip, Brett
Posted by Bud Gibson | November 3, 2006 11:37 PM
Posted on November 3, 2006 23:37