Jackknife Exercise - Target the Abs and Lower Back

Jackknife Exercise – Target Your Abs and Lower Back

One of the best ways to get in shape is by trying new exercises. The Jackknife exercise is a brilliant choice, and it’s even better when you combine it with sit-ups. Jackknifes work your core muscles and train your lower back muscles, often neglected in workouts.

However, jackknives require more than just a suitable form: you must be dedicated and do daily exercises for maximum benefits!

The Jackknife exercise comes as one of the most exhilarating workout routines. The sit-ups, in and outs, and crunch exercise does core some justice, but the jackknife is a more challenging workout. The jackknife puts focus on the whole body and primarily targets the abs.

The jackknife exercise is beneficial for both abs and the lower back. After a few weeks of the jackknife exercise, you will see significant results.

The optimum position for the movement is when you keep your legs straight during the activity. You can achieve significant results once you consistently perform the exercise daily.

How to do the jackknife exercise?

Start doing the jackknife exercise as you lie on the ground. Outstretch your arms and take them behind your head. Make sure your legs and arms raise upward as you do the movement.

This movement is quite simple to understand. You need to make sure you contract your abs and then fold in two. Bring your legs and arms together and meet above the midriff before moving them back towards the ground.

Keep your limbs straight as much as you can. However, only the most flexible people can maintain straight legs.

Therefore, make sure you don’t focus on bending your legs too much as they rise. Instead, try building a jackknife in a circuit session to ensure your core does not get off light.

The jackknife exercise is challenging. Therefore, don’t worry if it gets a bit too difficult initially. A more straightforward movement modification will work your muscles with lesser strain on your back. Thus this is the modified V-sit.

Also, you need to make sure you lie on your back and raise your feet. However, make sure that your arms stay at your sides this time.

Next, you must bend the knees and draw them towards your chest. Next, sit up and keep your arms straight so that your hands touch your feet. Finally, unfold slowly and return to the start point.

Physical skills improved

The jackknife exercise is perfect for engaging your core and making it more stable. It helps you perform activities well, such as running, rowing, and swimming. If you want to learn more about the exercise, you can keep reading below. With a stronger core, you can also create a well-balanced body.

Muscles worked

The jackknife’s primary muscles include the internal oblique, rectus abdominis, and external oblique. The side jackknife trains the outer and inner oblique muscles. Another name for it is the oblique V-up.

Incorrect form

Many people put all their stress on their necks when doing the jackknife exercise. Stressing your neck will not result in more benefits.

However, it will cause a strain on your neck. Also, this is because your arms don’t have a connection with this exercise. It is more about the rectus abdominis muscle than anything else.

You need to keep your arms beside you and not let them hover over the ground. Thus this is to prevent a neck-pulling habit. Also, you can bring the arms up in a crunch state if you don’t feel that crunch as you exercise.

Imagine that there is a tennis ball between your chest and chin. It would help if you kept the ball in shape as you performed the exercise.

Your neck will experience an intense force if you put your chin towards the palate of your mouth. Thus this will cause a sore neck that can lead to a headache.

You also need to ensure that your pelvis and spine stay neutral as you exercise. Also, this will help to engage your core.

Also, place the hip and pubic bones in a plane parallel to the ground. As you reach the pelvis in a neutral position, you will note the spine is creating a natural curve. As a result, you will maintain it as you do the crunch exercise.

Some people roll up towards the thoracic vertebra around the shoulder blades. Also, keep the pelvic region in a neutral position as you do the exercise.

Also, this will help you crunch up in a roll. However, don’t curl your neck and head forward; it will not keep your ab muscles in a proper position.

Some people do not expand their elbows wide enough to the side. As a result, the arms do not help you perform the jackknife exercise better.

So, engaging your pectoral muscles during the training is no use. It will only preoccupy your mind and prevent you from doing the correct form and engaging all the abs.

Make sure you move slowly and steadily as you perform the exercise. Getting too speedy will only lead to a strain. You do not have to go fast; instead, you need to go slow and in a more controlling position not to use any momentum.


1. Supine leg raise

For this variation, you need to lie on the ground and keep your core tight. Bring your legs from the floor to a vertical position over your hips. Go back down once again. Grip something so you can make sure your core is stable. You can bend your knees up to 90 degrees.

2. Ab station leg raise

You will need to bend your knees in this exercise and don’t go down. In addition, you need to make sure that your shoulders stay tight.

3. Pullup bar leg raises

The pullup bar leg raise is an exercise variation, including grip strength limitation. You must do a small movement arc and bend your knees.

However, don’t try doing this after or before any other exercise, which may tax your grip. Also, this includes deadlifts, rows, and pullups.

You can also start in a plank position and keep the legs and the torso tight. Now, bend right at the hip and lift your hips. Also, this will be the plank to the down-dog position.

4. Forearms in plank

Make sure your elbows are right under your shoulders. Clasp the hands together and do the same movement. It is the more extreme variation of abdominal exercise.

The arms stay in an external rotating position because of the forearms. The forearms will stretch your lats and your shoulders. You may keep the hands in a joining position.

Also, your arms will not be rotating externally to such an intense degree. Release the arms to sustain a broad supporting base and improve stability in the shoulders.

5. Gym ball exercise variation

You must keep your body forming a straight line from your head to your feet. Also, your hands need to be beneath your shoulders. Then, roll your feet over the gym ball. Finally, draw the knees towards your chest.

The Last Word on the Jack Knife Exercise

The jackknife is one of the best ways to get in shape. It works your core muscles and trains your lower back muscles, which you often neglect in workouts, and they’re exhilarating!

You can’t beat these exercises if you want to try something new that will impact your fitness routine.

However, it requires more than a suitable form – you must do it daily for maximum benefits. So what has been your experience with this exercise? Let us know in the comments below!

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