Sit-Up

When we think of a great set of abs, one exercise always comes to mind — the sit-up. It is a tried and tested bodyweight exercise that is great for carving out a ripped set of abs.

But what makes this movement so effective?

This article discusses why the sit-up is such a powerful ab exercise. It covers how to do it, anatomy, and expert tips to help you reveal a lean set of abs.  

How To Do

  1. Place a mat on the floor and lie down on your back.
  2. Bend your knees at a 90° angle and place your feet flat on the floor; hip-width apart.
  3. Place your hand behind your head, with your fingers interlocked, and elbows out to the side.
  4. Begin by tensing your core, and lifting your back off the ground.
  5. Lift until your torso is vertical, and your head is over your knees.
  6. Once you reach the top, slowly lower yourself back to the floor, until you reach the starting position.

Tips From Expert

  • Tense abdominals — Before each repetition, tense your core and curl yourself off the ground. This will engage your abdominal muscles and help you create a great mind-muscle connection, which has been shown to improve results. 
  • Focus on breathing — Concentrate on your breathing for the duration of your set. This can be done alongside your abdominal tensing. At the beginning of each rep, tense your core and exhale as you lift your back off the floor. Once you reach the top keep your core tight and inhale as you lower.
  • Perform slow-controlled repetitions Avoid using momentum and aim for slow-controlled repetitions when performing your sit-ups. Doing your set with control will ensure your abdominal muscles are working with each rep.

Optimal Sets and Reps

The sit-up is a versatile exercise used in many different workouts. Below is a list of ideal sets and repetition load recommendations to match your training goal.

Training Type Sets Reps
Strength Training 5 5
Hypertrophy 3–4 8–12
Endurance Training 3–4 15+
Power Training 3–5 3–5

How to Put in Your Workout Split

The sit-up is a simple and effective exercise that can be programmed into most workouts and split programs. Below is a range of suitable splits, and how you should consider programming your sit-ups.

  • Full Body — The full-body workout is the perfect session to program your sit-ups. Sit-ups should be placed at the end of the program, either during or after your isolation exercises. This will allow you to use more energy for your compound lifts at the beginning of your session.  
  • Bro Split — The sit-up can easily fit into any of your bro split workouts. Much like the full-body workout, it should be placed toward the end of each session. This is to ensure the bulk of your energy is spent on your compound lifts.   
  • Upper/Lower — The sit-up can be programmed for both your upper and lower body days. It is technically an upper-body targeting exercise, however, it can be performed either day.
  • Push/Pull/Legs — Again, the sit-up can be programmed in any of your push, pull, or days. Adding ab work doesn’t always need to match the exact workout. Placing it at the end of sessions is a great way to increase ab training volume, which can improve results.

Primary Muscle Groups

Upper Rectus Abdominis

Muscles located just below the lower chest and above the lower abdominals. Between your ribs and pubic bone.

Lower Rectus Abdominis

Muscles located below your upper abs and above your public bone between your ribs.

Upper Rectus Abdominis

The upper rectus abdominis is one of our main targets when performing the sit-up. Originating from the cartilage on ribs five to seven and inserting into the pubic crest, the rectus abdominis forms the abdominal six-pack.

During the sit-up, these muscles are the first to contract, flexing our spine and lifting our back off the floor. As we continue the sit-up, these muscles are engaged throughout the entire range of motion. They contract to lift us, and gradually lower us back to the floor. 

Lower Rectus Abdominis

The lower rectus abdominis is the lower portion of the same muscle and activates just after the upper rectus abdominis. During the sit-up, these fibers contract once our upper back is lifted off the floor, moving our spine into a fully flexed and upright position. 

These fibers are contracted throughout the entire top portion of the movement and remain engaged as we lower back down to the floor.

The sit-up is incredible because it has the greatest rectus abdominis fibers muscle activation of any ab exercise without equipment. 

Evidence indicates the sit-up to be the most effective exercise for the rectus abdominis, with lower fiber activation being higher than upper fiber activation.

Secondary Muscle Groups

Obliques

Muscles located on the sides of your rectus abdominals. Runs on the sides of your trunk.

Obliques 

The obliques are located on the outer sides of the torso, running lateral to the rectus abdominis. Consisting of the internal and external fibers, this muscle group is responsible for the rotation of the trunk and flexion of the spine. 

The muscle attaches from the fifth through twelfth ribs and is inserted into the iliac crest, pubis, and linea alba. During the sit-up, these fibers stabilize and flex the spine, contracting throughout the entire range of motion. 

Much like the rectus abdominis, research indicates the sit-up had the greatest level of muscle activation of traditional ab exercises.

Equipment

Bodyweight

Bodyweight

Requires bodyweight resistance and additional equipment for proper execution.

Variations

Exercises that target the same primary muscle groups and require the same equipment.

Plank Shoulder Taps

Bicycle Crunches

Inchworm

Dynamic Planks

Burpees

Twisted Mountain Climber

High Plank to Toe Touch

Hollow Hold

Sit-Throughs

Reaching Crunches

Dynamic Rollups

Reverse Plank

Lying Toe Touches

Walking Plank

Plank with Leg Lifts

Plank Jacks

Mountain Runner

One Arm Plank

Twisting Crunches

Alternatives

Exercises that target the same primary muscle groups and require the different equipment.

Who Should Do?

Fitness Enthusiasts

The sit-up is the perfect exercise for the everyday gym goer. It is a simple exercise that can be learned quickly and the research says is great for targeting our abs. 

If you mention the sit-up, just about anybody will understand what you are talking about, making it perfect for beginners. Even better, it can be scaled with additional weight or added to a 30-day ab challenge. This allows you to continue progressively overloading the abs to increase muscle hypertrophy.  

Athletes

A strong, robust set of abs are invaluable to athletes as they help control movement and stability. By adding the sit-up to your training program, you will be able to not only increase abdominal strength but also improve your mind-muscle connection. This will allow your body to recruit the fibers of the rectus abdominis and obliques, which are pivotal during competition.

Bodybuilders

If there was ever a group of athletes that should do the sit-up, it’s bodybuilders. Bodybuilders train for size and symmetry, and each repetition they perform is about developing their mind-muscle connection.

This makes the sit-up the perfect fit as it is incredible for rectus abdominis activation. It can also be scaled using weight plates and cables providing the progressive overload necessary for muscle growth.   

Who Should Not Do?

People With Lower Back Pain

If you suffer from lower back pain, you should avoid the sit-up. The sit-up targets the core to improve support for the lower back. However, the flexion required for the movement may aggravate lower back pain. 

Lower back pain can be caused by muscle, ligament, or disc damage. When we curl our body up during a sit-up, pressure is placed on these structures.   

Now, this is not to say you should avoid adding core work, as abs workouts with lower back pain can be done.

Instead, consider adding exercises that don’t require spinal flexion, such as planks, and dead bugs. These will help you build up core endurance without aggravating your lower back. 

People With Abdominal Injuries

The sit-up is not suitable for anyone with an abdominal injury. This is because the sit-up targets the rectus abdominis and obliques, and additional stress may cause aggravation.

If you are currently nursing an ab injury, your best course of action would be to seek assistance from a physical therapist. They can provide you with safe rehabilitation exercises that will help you build up your core strength.  

People With Hip Flexor Injuries

If you have an existing hip flexor injury, you should avoid doing sit-ups. The hip flexors are located at the front of our hip and are responsible for lifting the knees. 

However, when we perform the sit-up, these muscles activate to stabilize and support us throughout the movement. If the muscle tissue is damaged, these movements can cause further aggravation. 

Alternatively, consider performing abdominal exercises that don’t require spine and hip flexion, including planks, side planks, and the Pallof press. These will allow you to target the abs without risking further injury.    

Benefits Of The Sit-Up

Improved Core Strength

The sit-up is one of the easiest ways to improve our core strength. As mentioned, the sit-up has the greatest rectus abdominis muscle activation of all standard core exercises. 

By performing the sit-up regularly, you can develop a stronger core, which can enhance your other lifts and improve your quality of life.

Increased Muscle Mass

Targeting your abs using sit-ups is an excellent way to increase abdominal muscle mass. Much like other muscles, progressively overloading the abs will increase their mass.

To ensure you are loading for muscle growth, perform 3–4 sets of 8–12 repetitions at 60%-80% of your one repetition maximum (1RM). Working within these repetition ranges has been shown to enhance muscle hypertrophy.  

Reveals Athletic Physique

The sit-up is an exercise that works wonders for revealing our lean muscular physique. While building a bigger back, shoulders, and biceps makes you look massive, nothing says you are ripped like a chiseled set of abs.

Sit-ups will create muscle mass and abdominal definition that can taper our waistline. This makes our shoulders, chest, and arms appear bigger, enhancing our overall physique.

Can Be Done Anywhere

One of the best things about sit-ups is that they can be done anywhere. Often when we find a great exercise in the gym, it can be difficult to replicate it without the exact equipment. 

The sit-up doesn’t need any additional equipment to be effective. However, if you want to increase resistance, you can use just about anything to add weight, including water bottles, backpacks, or weights. 

This means that there are no excuses, so place it alongside other bodyweight ab exercises for a killer workout.

Frequently Asked Questions

Does the sit-up burn belly fat?

Yes, sit-ups burn belly fat. However, it does so by burning fat from the entire body as there is no such thing as spot reduction. A calorie deficit alongside an ab routine will help you burn fat, revealing your abs.

Is it okay to do sit-ups every day?

Yes, it is okay to do sit-ups every day. Our abs are robust muscles that are capable of being trained every day. However, if you are experiencing fatigue or soreness, consider taking a day to rest. 

What are the disadvantages of sit-ups?

The disadvantage of sit-ups is they can strain the back. During the sit-up, our spine flexes, placing pressure on our back, which can cause discomfort or aggravate an existing injury.

Resources

  1. Calatayud, J., Vinstrup, J., Markus Due Jakobsen, Sundstrup, E., Brandt, M., Jay, K., Juan Carlos Colado and Lars Louis Andersen (2015). Importance of mind-muscle connection during progressive resistance training. European journal of applied physiology, [online] 116(3), pp.527–533. doi:https://doi.org/10.1007/s00421-015-3305-7.
  2. Schoenfeld, B.J., Grgic, J., Van, D.W. and Plotkin, D.L. (2021). Loading Recommendations for Muscle Strength, Hypertrophy, and Local Endurance: A Re-Examination of the Repetition Continuum. Sports, [online] 9(2), pp.32–32. doi:https://doi.org/10.3390/sports9020032.
  3. Sevensma, K.E., Leavitt, L. and Pihl, K.D. (2023). Anatomy, Abdomen and Pelvis, Rectus Sheath. [online] Nih.gov. Available at: https://www.ncbi.nlm.nih.gov/books/NBK537153/.
  4. Oliva-Lozano, J.M. and Muyor, J.M. (2020). Core Muscle Activity during Physical Fitness Exercises: A Systematic Review. International journal of environmental research and public health/International journal of environmental research and public health, [online] 17(12), pp.4306–4306. doi:https://doi.org/10.3390/ijerph17124306.
  5. Flynn, W. and Vickerton, P. (2023). Anatomy, Abdomen and Pelvis: Abdominal Wall. [online] Nih.gov. Available at: https://www.ncbi.nlm.nih.gov/books/NBK551649/.‌
  6. Plotkin, D., Coleman, M., Derrick Van Every, Maldonado, J., Oberlin, D., Israetel, M., Feather, J., Alto, A., Vigotsky, A.D. and Schoenfeld, B.J. (2022). Progressive overload without progressing load? The effects of load or repetition progression on muscular adaptations. PeerJ, [online] 10, pp.e14142–e14142. doi:https://doi.org/10.7717/peerj.14142.