Jack Knife Modifications
This week I’ve got one of our most popular core exercises – the Jack Knife – and a couple of more advanced variations of the movement. We do this exercise plenty in classes, but some of you still may not be familiar with the terminology or some of the advanced modifications. Pretty simple add-ons to the exercise, but they make it much more difficult. On all three movements, focus on keeping your chest up to prevent rounding of the back.
The hands are down for balance purposes on the basic movement here. The less you lean on your hands, the more core activation you will get here.
Advanced Jack Knife
The only difference here, as you can see, is the hands are elevated. This will not only make the movement harder in terms of holding your chest up, but balancing your body, as well.
Situp Jack Knife
This time we’ve added a full situp into the movement. As you can see on the first rep, I touched my feet down to the ground. This allows for a slight break in between reps. For an even tougher challenge, keep your feet off the ground like I have done for the final few reps.