Crunches are strength training exercises that work your abs and oblique muscles. They are simple to do and do not require any equipment.
When done regularly, crunches can lessen back pain and help you lose calories.
This article covers everything you need to know about the crunch exercise and how many calories you can burn doing the crunches.
What are crunches?
The crunch is a core strengthening exercise that involves raising your upper body a few inches from the ground and back.
Crunches specifically target your rectus abdominis (often referred to as the six-packs) and strengthen your back and hips.
They are good warm-up exercises for rigorous strength training.
Benefits of doing crunch exercise
Aside from working your core muscles, the crunch exercise also comes with the following benefits.
- It improves posture and balance
- May relieve back pain
- It is beginner-friendly, and you can do it anywhere.
- It does not require any special equipment.
How many calories do crunches burn?
Crunches burn only a small amount of calories, and this amount is dependent on several factors, including the individual’s weight and training duration.
The following are factors that influence your calorie burn during crunches.
This is a significant determinant of how many calories you burn in any exercise. The more you weigh, the more calories you’ll lose.
For example, a person weighing 155 pounds will burn about 55 calories in 10 minutes of moderate-intensity crunches, while a 185 pounds man will burn 66 calories doing the same exercise.
Like other exercises, the more time you spend doing the crunches, the more weight you lose.
If you weigh around 170 pounds, you will burn about 17 calories in 3 minutes of working out. However, if you train regularly for 5 minutes, you can burn up to 29 calories each time.
The more rigorous your crunch training, the more calories you’ll lose.
For example, a 125 pounds man that typically loses 20 calories in 5 minutes will burn more fat if he crunches at a more vigorous pace.
How to calculate your crunch calorie burn
You can use a calories-burned calculator to calculate your crunch calorie burn. These calculators are available online. However, for a more accurate calorie measurement, use the formula below.
Number of calories burned per minute = [MET × 3.5 × your weight (in kg)] / 200
Note that the MET of crunches varies according to the intensity. Light-intensity crunches have a value of 2.8 and 3.8 for moderate effort. The MET of high-intensity crunches is about 8.
So, if you weigh 70kg, you will burn 4.7 calories while crunching for one minute.
(To calculate your weight in kg, divide your weight in pounds by 2.2).
How to do the crunch exercise
Crunches are pretty easy to do.
To begin, lie with your back on the floor. While keeping your legs together, bend your knees backward, so your feet rest firmly on the ground.
Place your hands across your chest or behind your ears. This will help to stabilize your neck. Next, slowly lift your head and shoulder blade slightly above the ground.
Contract your abdominals as you do this and exhale as you rise. Hold the position for a few seconds and inhale as you lower your back down. Perform three sets of 15 reps.
Tips to correctly perform crunches exercise
- Keep your neck neutral and your chin up.
- Avoid rapid and abrupt movements.
- Don’t jerk the shoulders too high or more than 2 inches; the aim is to challenge your core.
- Try not to push your head forward with your hands – the movement for the exercise should come from your abs, spine, and lower back.
- Keep the tension on the abs throughout the movement. Don’t wholly relax your shoulders on the ground.
Types of crunches
Like the fire hydrant exercise, there are also several ways to do the crunches. The following are the most common types of crunch exercises.
First, stand with your feet more than shoulder-width apart and place your hands behind your head.
Raise your left knee to your chest and slowly lower your torso so the right elbow touches or points towards your left knee.
Next, lower your knee to return to the start position. Repeat on the right leg and do three sets.
In this exercise, both your legs are slightly above the ground.
To begin, move to a crunch position and start to ride your legs in the air. Move your elbows towards the opposite leg as you ride.
Repeat 10 to 12 times for five rounds.
In this exercise, your knees move slightly to reach your chest.
While lying on your back, lift your lower back off the ground by tightening your lower abs. Flex your knees and keep them slightly elevated from the ground.
Bring your knees towards your chest as you crunch. Do five reps of 3 sets.
This exercise also works your leg muscles.
Lie on your back with your legs extended in the air and your hands slightly under your buttocks.
Lift your head and shoulders off the ground, tightening your abdominals. Only your lower back, hands, and buttocks should touch the ground.
With your left leg higher than the other, begin to swing your legs sideways and back in a scissor-like motion. Continue for ten seconds. Do three reps.
How many calories will I burn doing 100 crunches?
An average person can do 30 crunches in a minute, thereby burning around five calories in one minute. So, if you complete 100 crunches, it means you’ll spend 3.3 minutes on the exercise.
To find out how many crunches you’ll burn in 100 crunches, calculate the number of calories you burn in a minute, and then multiply the value by 3.3, that is the time it takes to perform 100 crunches.
An average person would burn around 16.6 calories with 100 crunches.
How many crunches should you do each day to lose weight?
This depends on your weight loss goal. Since one pound (0.45kg) of fat equals 3500 calories, you can calculate how many crunches you need to do to lose one pound in a day or week.
To shed one pound (0.45kg) in one week, you’ll have to do 3,125 crunches a day. This means you have to spend about one hour 44 minutes (104 minutes) doing crunches every day.
This figure is unreasonable and suggests that crunches are not ideal for weight loss.
Under normal conditions, you will burn about five calories in one minute of doing the crunches. Walking, running, and cycling are better ways to burn fat than crunching.