Fitness Volt
  • Bodybuilding
  • Strongman
  • Powerlifting
  • Workouts
    • Training
    • Exercise Guides
    • Workout Plans
    • Celebrity Workouts
    • Training Programs
  • Nutrition
    • Diet
    • Fasting
    • Diet Plans
    • Nutrition Tips
    • Supplements
    • Food Facts
  • Reviews
  • More
    • CrossFit
    • News
      • 2023 WSM
      • Arnold Classic
      • Mr. Olympia
      • Results
    • Fitness Calculator
    • Mastering The Deadlift
    • Profiles
    • Motivation
    • Videos
    • MMA
No Result
View All Result
Fitness Volt
  • Bodybuilding
  • Strongman
  • Powerlifting
  • Workouts
    • Training
    • Exercise Guides
    • Workout Plans
    • Celebrity Workouts
    • Training Programs
  • Nutrition
    • Diet
    • Fasting
    • Diet Plans
    • Nutrition Tips
    • Supplements
    • Food Facts
  • Reviews
  • More
    • CrossFit
    • News
      • 2023 WSM
      • Arnold Classic
      • Mr. Olympia
      • Results
    • Fitness Calculator
    • Mastering The Deadlift
    • Profiles
    • Motivation
    • Videos
    • MMA
No Result
View All Result
Fitness Volt
No Result
View All Result
Core
Fact Checked
Fact Checked
This article was written by one of our qualified writers, and fact-checked by our experts. The numbers in parentheses (e.g. 1, 2, 3, etc.) throughout the article, are reference links to peer-reviewed studies.
Our team of experts include a board-certified physician, nutritionists, dietitians, certified personal trainers, strength training experts, and exercise specialists.
Read Our Editorial Process

How to Do Jackknife Sit-Ups Exercise Guide and Videos

This is a killer core exercise that doesn't require any equipment. Learn how to do it with tips, variations and more.
Matthew Magnante

Written by Matthew Magnante

Updated by Brad Borland, M.A, C.S.C.S

Last Updated onFebruary 27, 2023

Jackknife Sit Up Exercise

Jackknife Sit Up Exercise

The jackknife sit-up is an intermediate to advanced ab exercise that only requires your body weight and a little more movement than a basic ab crunch or standard sit-up.

It’s a great option if you really want to challenge yourself and will activate the entire group of core muscles.

Learn how to do it with tips, variations, and more in this exercise guide.

In This Exercise:

  • Target Muscle Group: Iliopsoas, rectus abdominis
  • Type: Hypertrophy, function
  • Mechanics: Compound
  • Equipment: Exercise mat
  • Difficulty: Intermediate, advanced

Jackknife Sit-Up Muscles Worked

There are several muscle groups involved in the jackknife sit-up. Here are descriptions of each one. 

Iliopsoas

Iliopsoas has a big role in performing the major flexion of the hip joint. It’s not just one muscle but rather a psoas major and minor and an iliacus which can also function separately. Lifting the legs up will utilize a lot of hip flexor strength. 

Jackknife Sit Up Muscle Worked

Rectus Abdominis

Jackknifes are utilized for their ab building prowess and they, like other similar variations can improve your core development if you do them properly. The rectus abdominis performs a crunching motion at the upper and lower torso which is needed to effectively execute jackknifes. 

Adductor Brevis

The adductor brevis works as the name implies, to adduct or bring the thigh toward the opposite leg or inward. You’ll need to include some activation of these muscles to help keep your legs together as you lift them up and down. 

Adductor Longus

The adductor longus is a strong adductor like its family members, the adductor brevis and magnus. 

Tensor Fasciae Latae

We use muscles that majority of the population would never know of and tensor fascia latae is one of those, however, an important muscle group. With the gluteus medius and gluteus minimus, the TFL internally rotates and abducts the hip but also assists the rectus femoris in the flexion of the hip, and assists in pelvis stability when standing and walking.

How To Do The Jackknife Sit-up

While this isn’t necessarily a complex movement, you might benefit from a few tips to ensure you do it right and get the most from it. 

Here are step-by-step instructions for the jackknife sit-up.

  1. Lie on your back with your arms extended overhead and legs straight out. 
  2. Keeping your legs straight or knee slightly bent, engage your core and simultaneously bring your feet and arms together over the middle of your body. You should try to touch your ankles at the top.
  3. Bring your legs and arms back into the starting position and repeat for the desired number of reps. 

Here’s a video example…

Jackknife sit-up tips

  • You want to make sure to keep your core muscles nice and tight. Simply going through the motions will not engage your midsection as effectively and that defeats the purpose of the movement. 
  • You can bend your knees if you cannot keep your legs straight.
  • The arms and legs should move up and toward each other at the same time. 

Jackknife Sit-up Benefits

There are a few benefits of doing this sit-up variation. 

Improve core development

This is an ab-focused movement which means most exercisers do it because they believe it will help to improve the appearance of their core muscles. 

Well, done right and intensely enough and it can certainly contribute to the development of your abdominal muscles. 

Strengthen your midsection

This exercise also helps to increase your core strength. 

A strong midsection is crucial for all lifting and physical activities as it keeps your body rigid and supportive, stabilizes your spine, and protects your lower back. 

Don’t need equipment

The jackknife sit-up requires no workout equipment to do which means it can be done almost anywhere. 

It’s fun and you can make it more challenging

While the jackknife sit-up is an effective core exercise, it also provides a challenge and is a great option for adding some versatility to your training. 

You can include it in supersets, circuit training, workout challenges, and more.

Not to mention, you can add ankle or wrist weights or hold some dumbbells and make it much more challenging. 

Jackknife Sit-Up Variations

The jackknife sit-up is a great ab exercise but there are similar ones that you may like as much or better, and some are easier which makes them ideal for beginners. 

Cocoons

Cocoons are a similar exercise to the jackknife sit-up but it’s arguably easier to do. The movement resembles insect cocoons when performed properly. 

You could also use it as a progression to jackknife sit-up.

Lying straight leg raise

The lying straight leg raise involves only lifting the legs without moving the arms. Many believe leg lift variations emphasize the lower portion of the abdominals and it may. But you cannot necessarily target the lower abs.

This exercise can help to increase hip flexibility to be able to perform exercises like the jackknife sit-up.

Using The Jackknife Sit-up Into Your Training Routine

It’s not rocket science really. The jackknife sit-up can fit into your routine in many different ways and there are no rules. But we do think a little strategy can make your training more enjoyable and productive. 

For example, you might use this exercise as part of a superset. Or, you could choose several exercises and so a circuit with the jackknife sit-up being thrown in somewhere. 

But you could also do it with other core movements or on its own as a finisher since it’s challenging and intense. 

Sets/reps

The best way to perform bodyweight ab exercises is to train to failure. That’s because, for many, doing more than a few reps is necessary to challenge the muscles. 

We would recommend a minimum of 2 sets for this exercise and reps to failure.

Wrapping Up

The jackknife sit-up is a must-have bodyweight core exercise. It doesn’t require equipment which means you can do it anywhere but it’s also very challenging once you do enough and if you have the mobility and flexibility. 

You can include it in your workouts any way you like but just make sure to do it correctly. 

Stay on top of the latest fitness news and updates by adding Fitness Volt to your Google News feed: Follow us on Google News You can also follow us on Twitter, Facebook, Instagram, and YouTube for even more content.
Facebook Twitter Reddit Flipboard LinkedIn Pinterest
Categories: Core Exercise Guides Legs and Glutes
Previous Post

Josh Silvas And Nicolas Cambi Win America’s Strongest Man And America’s Strongest 105kg Man

Next Post

Powerlifter Tamara Walcott Deadlifts 636lb For All-Time World Record

Matthew Magnante

Matthew Magnante

Matthew is an ACE (American Council On Exercise) certified fitness professional who has had a passion for fitness since elementary school and continues to research and learn how to build muscle effectively through training and diet. He also loves to help others to achieve their fitness goals and spread the knowledge where needed. Matthew's other passions include learning about mindfulness, strolling through nature, traveling, and always working to improve overall.

Related

Band Side Bend Exercise

How To Do The Band Side Bend: Benefits, Common Mistakes, and Variations

When you're bored of those lying and sitting side crunch variations or ran out of options to train your obliques...

Isometric Training Explained

The Science of Isometric Training — Explained!

Can you build a stronger and more aesthetically appealing physique by not moving? Wild idea, but that’s what isometric training...

Arnold Schwarzenegger

Arnold Schwarzenegger Unveils His 3-Tier ‘Hierarchy of Muscle Gains’

Arnold Schwarzenegger is a living legend who credits much of his success to health and fitness. He's a former seven-time...

Rich Gaspari

Rich Gaspari Shares Abs Exercise for Strength & Training Intensity Tip for Hypertrophy: ‘Total Annihilation’

Bodybuilding veteran Rich Gaspari is a strong proponent of using intensity to enhance his package in the gym. Although he...

Best Standing Abs Exercises

The 17 Best Standing Abs Exercises for All Fitness Levels

We love floor-based abs exercises as much as the next guy, but sometimes it’s nice not to have to lie...

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Latest

Liver King Asks for Prayers and Blessings, Doctors Say He’s Going to ‘Lose Eye’ from Recent Injury

Malcolm Cooper Victorious at 2023 WNBF Pro Universe, Claims Mr. Universe Title 

Mitchell Hooper Compares Himself To Prime Hafthor Bjornsson and Eddie Hall

Shawn Ray Says Terrence Ruffin Can Dethrone Chris Bumstead ‘If He Misses His Peak’ at 2023 Olympia 

“I Can Win” — Brandon Curry Talks Prep and 2023 Mr. Olympia Ambitions 

Powerlifter Stanley Odin (+120KG) Sets Huge Squat & Total Raw French Records at 2023 FFForce French Nationals

Reviews

Best Pre Workout Supplements

20 Best Pre-Workout Supplements: Expert Review & Ranked (2023 Update)

Best Foldable Weight Benches

10 Best Foldable Weight Benches for 2023 (Review & Ranked)

Best Treadmills For Heavy User

10 Best Treadmills for a Heavy Person in 2023 (Review & Ranked)

Fitness Volt

At FitnessVolt.com Our mission is to help our readers to achieve their fitness goals, regardless of where you’re at on your journey, we are on a mission to educate You with the latest from strength and fitness space. Read more.

Email: sm(at)fitnessvolt.com

Disclosure: FitnessVolt.com has an affiliate relationship with different brands and is a participant in the Amazon Services LLC Associates Program. However, our reviews are based on well research backed analysis.

Follow Us

Trending Topics

  • Mr. Olympia
  • Bodybuilding
  • Strongman
  • Powerlifting
  • CrossFit
  • At Home Workouts
  • Bodyweight Exercises
  • Best Pre-workout
  • Best Fat Burners
  • Bodybuilding Diet
  • Bicep Workouts
  • Triceps Workouts
  • Chest Exercises
  • Back Workouts
  • Leg Workouts
  • Front Squat Guide
  • Calf Workouts & Exercises
  • Forgotten Exercises
  • Jefferson Deadlift

Calculators

  • Calorie Burning Calculators
  • IF Calculator
  • TDEE Calculator
  • Calorie Calculator
  • Keto Calculator
  • RMR Calculator
  • Macronutrient Calculator
  • Creatine Calculator
  • Wilks Calculator
  • EER Calculator
  • FFMI Calculator
  • IBW Calculator
  • LBM Calculator
  • Fat Intake Calculator
  • Calories Burned Swimming
  • Calories Per Meal Calculator

  • Food Nutrition Analysis
  • Carb Cycling Calculator
  • Weight Gain Calculator
  • Weight Loss Calculator
  • Calories Burned Calculator
  • Strength Standards
  • One Rep Max Calculator
  • Body Fat Calculator
  • EER Calculator
  • Weight Loss Percentage
  • Treadmill Calorie Calculator
  • Body Surface Area Calculator
  • Running Pace Calculator
  • Bench Press Calculator
  • Protein Calculator
  • Water Intake Calculator
  • Body Type Quiz
  • Steps to Miles Calculator
  • Calorie Deficit Calculator
  • Home
  • About
  • Jobs
  • Accessibility
  • Advertise
  • Contact
  • Syndication
  • Sitemap
  • DMCA
  • Copyrights
  • Terms
  • Privacy
  • Cookies
  • Disclaimer

© Copyright 2010 - 2023 Fitness Volt IBC. All Rights Reserved.

No Result
View All Result
  • Bodybuilding
  • Powerlifting
  • Strongman
  • CrossFit
  • Workouts
  • Exercise Guides
    • Arms
    • Back
    • Chest
    • Core
    • Legs and Glutes
    • Shoulders
    • Yoga
  • Training
  • Nutrition
    • Diet
    • Fasting
    • Diet Plans
    • Supplements
    • Nutrition Tips
    • Food Facts
  • Reviews
  • Fitness Calculator
  • More
    • News
    • Mastering The Deadlift
    • 2023 WSM
    • Arnold Classic
    • Mr. Olympia
    • Diet
    • Motivation
    • Videos

© Copyright 2010 - 2023 Fitness Volt IBC. All Rights Reserved.