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Muscles Worked With Sit-ups

Most people know that resistance training exercises can help you build muscle. But what specific muscles do sit-ups work out?

Sit-ups are an exercise where you start lying down on your back with your feet on the ground. After that you curl up your upper body until your chest is at your knees. If you want you can hold some form of weight against your chest or in your hands.

If you do sit-ups right you mainly engage your ab and oblique muscles. Besides that, your hip flexors also have to work. If you hold a weight some arm, shoulder, and back muscles will have to exert a small amount of effort too.

Keep in mind that sit-ups can be hard on your lower back, hips, neck, and shoulders even if you implement the right technique. Especially if you add weights. Whether you should add them to your routine depends on things like your personal situation and training goals.

How to do a sit-up

Main muscles worked with sit-ups

With any exercise you will almost always make a variety of different muscles work. Even so, there are a few muscles that will have to work the hardest for moving and keeping your body in position.

For most people, the ab and oblique muscles will be the first to fatigue when doing sit-ups with the right technique. Besides that, your hip flexors will have to work hard too.

If working out your core muscles is your goal make sure your curl your shoulders off the ground first. As you get closer to your knees more and more of your upper body gets off the ground.

Holding the weight in front of your chest also engages your biceps, traps, back, shoulders, and forearms to some extent. That being said, if you want to train these muscles there are plenty of more helpful exercises.

In short, sit-ups are mainly an exercise for training your oblique and ab muscles. To build the most muscle mass you want to do about 4 sets of 10-40 sit-ups depending on how advanced you are.

How to make sit-ups harder

The way you build muscle in places like your obliques and abs is by engaging these muscles so that they get damaged enough. This may sound counterintuitive but this damaging makes it so your body repairs these muscles, and adds a bit more to be better prepared to exert similar efforts in the future.

If you stick to exercises with the same weight, as your muscles become stronger this same effort may not damage your muscles enough to promote extra muscle growth.

As a strength training beginner, and possibly even intermediate, sit-ups can be a great bodyweight exercise to train your abs and obliques. That being said, at some point your body weight may stop being enough resistance to build a lot of extra muscle mass with this exercise.

At this point, you need to turn to other core exercises or make sit-ups harder to keep building a lot of extra muscle. Working up to 100 sit-ups a day is usually not the best idea. Making sit-ups harder at the right points in your training journey can also speed up muscle growth.

One of the benefits of sit-ups is that you can easily use a wide variety of objects to make this exercise harder. Even if you don’t have typical fitness objects like a medicine ball, dumbbells, kettlebells, etc. you can use a heavy backpack or grocery bag.

Simply hold one of these objects against your chest or in your hands while doing sit-ups to make the exercise more challenging.

If you decide to implement more sit-ups make sure you give your body enough nutrients, rest, and sleep to repair and grow your muscles.


Matt Claes

Matt Claes founded Weight Loss Made Practical to help people get in shape and stay there after losing 37 pounds and learning the best of the best about weight loss, health, and longevity for over 4 years. Over these years he has become an expert in nutrition, exercise, and other physical health aspects.