Sit ups are classic abdominal exercises performed by lying on your back and lifting your torso. During execution, body weight is used as resistance to strengthen and tone the abdominal muscles, which stabilize the core.
Sit ups work the rectus abdominis, transverse abdominis and obliques, as well as the hip flexors, chest and neck. They promote good posture, as they work the lower back and gluteal muscles.
This abs exercise requires nothing but your body weight, so it’s very versatile and you can do it anywhere.
What is the sit up and why perform it
A sit-up is an abdominal exercise that improves your core muscles, and more. The rectus abdominis, the muscle that runs vertically along the front of the torso, is particularly engaged throughout the movement.
Sit-ups also strengthen the hip flexors, which connect your thighs to your lower back.
According to studies, it helps build a stronger core and by doing so, reduces the chances of injury and improves athletic performance. That’s why you should incorporate it into your workout routine.
With a broad range of motion, sit ups engage more muscles than crunches and isometric abdominal exercises, such as planks.
If your goal is to strengthen your core, incorporating sit ups into your workout routine is your best bet. The movement while running can also aid digestion, as it strengthens the abdominal muscles that allow the intestines to function properly.
Sit-ups: the muscles involved
It is one of the best known abdominal exercises, and involves the following muscle groups:
- Rectus abdominis.
- Internal and external obliques.
- Transverse abdomen.
- Hip flexors (iliopsoas and rectus femoris).
Rectus abdominis: This is the main abdominal muscle that runs along the front of the torso, which makes up the so-called “six-pack” and is the main muscle people refer to when they talk about abs.
The rectus abdominis is often divided into the “upper or upper abs,” those above the belly button near the lower chest, and the “lower abs,” below the belly button. It’s actually a single muscle, and research shows that these two separate sections can be activated to varying degrees by certain exercises.
Abdominal exercises with torso movement, such as sit ups, typically emphasize the upper abs while ab exercises with leg movement emphasize the lower abs.
Hip flexors: The hip flexors are a group of several small muscles found near the top of each thigh, connecting to the pelvis and lumbar spine (lower back). They serve to bring the upper leg closer to the chest.
Because the hip flexors connect to the lumbar spine, they are strongly associated with contributing to or relieving back pain depending on the strength, flexibility, and range of motion of the muscles.
If you are interested in the topic, discover our study on the anatomy of the abs.
How to do the correct exercise
Performing a sit up is quite simple, the main thing to pay attention to is the position of the back, to avoid muscle tension and injury. Here’s how to do the exercise correctly:
- On a mat, lie down. Keeping a hip-width distance between your legs, bend your knees and place your feet flat on the floor.
- Press your lower back into the floor while keeping your hands on the sides of your thighs (or behind your head).
- Activate your core. Inhale keeping your neck in line with your spine and looking diagonally towards the ceiling.
- Exhale and come to a sitting position using your core muscles. Maintain comfortable shoulder posture.
- Inhale and slowly return to the starting position. Remember to keep your lower back flat on the mat.
If you feel tension in your lower back during a set, move your feet slightly further away from your body and slightly wider apart. If you’re a beginner, do the sit-up with your body weight for 2 to 3 sets of 10 to 20 repetitions, with 30 seconds of rest between sets.
Add external resistance and perform 3 to 4 sets of 6 to 12 reps, with one minute rest between sets. The exercise technique with and without weight is identical. The added weight shouldn’t compromise your shape.
All the benefits of the sit up
They are basic exercises, which have different benefits for the body. Let’s see them specifically.
Greater strength in the core
Core strength is one of the biggest motivations for doing sit-ups. By strengthening, contracting, and toning your core, you reduce your risk of back pain and injury.
They improve muscle mass
Sit ups build muscle strength in the abdominal and hip muscles.
According to 2016 research, older women who were able to do sit-ups were less likely to suffer from sarcopenia, the natural loss of muscle that comes with aging.
In fact, women who were able to do more than 10 sit-ups had higher levels of muscle mass and greater function. While these results are promising, more research is needed to expand this data.
Better athletic performance
Strong core muscles are linked to improved muscle strength and endurance in athletes. A strong core improves posture and stability, allowing you to improve athletic performance as well. Plus, as you get stronger you will, of course, be less fatigued after your workout.
Improve balance and stability
A strong core helps keep your body balanced and stable as you move through your daily activities. Good balance therefore decreases the risk of falls and injuries.
Greater flexibility
Moving the spine helps loosen stiffness in the spine and hips.
Sit ups make your hips and back more flexible, which increases range of motion and relieves tension. Increased flexibility also improves circulation and concentration, reduces stress and increases energy levels.
Improved posture
Building a strong core makes it easier to keep your hips, spine and shoulders aligned, which improves your posture, and will make you feel less pain and tension, increase your energy levels and improve your breathing.
Strengthening of the diaphragm
Sit ups are a great way to practice diaphragmatic breathing.
The reason? They cause compression of the abdomen, which can have a positive effect on the diaphragm. A strong, healthy diaphragm can improve breathing, relieve stress, and improve athletic endurance.
A small 2010 study looked at the effects of different abdominal exercises on diaphragm pressure, and it was found that sit ups were helpful in strengthening the diaphragm and improving respiratory function.
Alternatives and variations of the sit up
Since the sit up is a relatively simple exercise, here are some variations on the basic movement that can recruit or emphasize different muscles for a more varied stimulus.
Sit up twist
Sometimes called knee-to-elbow sit-ups, twist sit-ups involve a twisting motion that recruits the oblique muscles—those that run along both sides of the rectus abdominis.
Rather than ending with the chest directly in front of the thighs and knees, this exercise involves bringing the chest toward the right knee first and then the left.
It’s common to alternate sides on each rep, but reps can also be done all on the same side.
Straight leg sit-ups
The straight-legged sit-up is performed with the legs straight and heels on the floor, rather than with the legs bent and feet flat on the floor.
This increases overall range of motion, and significantly intensifies hip flexor recruitment.
This is a very similar exercise to the Pilates roll-up.
- In this case you start from the sitting position, with your legs straight in front of you.
- From here, slowly and always activating the core, descend towards the floor trying to keep your back in a neutral position.
Sit-ups with weights
This exercise is performed with a weight to be held in the hands and carried above the head.
This variation is performed by keeping both arms straight and pointing towards the ceiling, throughout the repetition.
As an even more advanced variation, you can hold a light dumbbell in each hand or a disc in both hands. This will also engage the shoulder muscles, especially the smaller stabilizer muscles of the shoulder, and the upper back. Here’s how to do it:
- Lie on a mat with feet flat on the floor and knees bent.
- Press your lower back into the floor by holding your arms high in front of you and holding a weight.
- Activate your core, inhale keeping your neck in line with your spine and looking diagonally towards the ceiling.
- From here, exhale and come to a sitting position using your core muscles. Maintain comfortable shoulder posture.
V Sit-up
Another very popular variation of the classic sit up is the V sit up. Here’s how to do it:
- Lie on your back with your legs straight and your arms extended above your head.
- Simultaneously lift your feet and arms towards the ceiling.
- Bring your arms parallel to the floor.
- Hold this position for about 5 seconds.
- From here, slowly lower your back down to the starting position.
Butterfly sit-up
To perform the butterfly sit up, here’s how:
- Lie face up on the mat, arms extended over…
