If you can do 100 sit-ups in a row, chances are you're pretty fit. But you still might have some extra pounds to shed if you want to see all the hard work you've done on your abs.
How many calories you'll burn doing 100 sit-ups depends on your weight — but it will be minimal. You can burn more by increasing the challenge of your sit-ups and incorporating them into a fast-paced workout including other exercises.
Calisthenics and Calories
Sit-ups are a type of calisthenics. This is a broad description of exercises you do with only your body weight. Other examples include push-ups, pull-ups and body weight squats. Typically, you do one or more sets of a set number of repetitions and then move onto the next exercise.
Without wearing a heart monitor, the best you can do is estimate how many calories you burn. According to estimates on the Harvard Medical School website, the average adult will burn 135 to 200 calories in 30 minutes of calisthenics.
At that rate you're burning 4.5 to 6.7 calories per minute. Assuming it takes you 3 to 6 minutes to complete 100 sit-ups, you would burn 13.5 to 40 calories.
Factors That Influence Calorie Burn
The reason for the range is body weight. Theoretically, the heavier you are the more calories you'll burn doing a particular activity, because it takes more energy to move your body through space.
According to weight, the calorie breakdown for 100 sit-ups in 3 to 6 minutes looks like this:
- 125 pounds: 13.5 to 27 calories
- 155 pounds: 16.7 to 31 calories
- 185 pounds: 20 to 40 calories
If you weigh more or less than these numbers, you may burn more or fewer calories.
Increase Your Calorie Burn
There's no hard evidence to support that changing the type of sit-ups you do will increase your calorie burn. However, it is widely accepted that the harder you work, the more calories you burn.
Doing 100 traditional sit-ups is challenging for most people. But if you're at the point where you're ready for more, you can potentially increase your calorie burn by doing harder variations of sit-ups.
For example, you could try doing your sit-ups at a slower tempo; slowing things down often makes exercises harder because you're not benefitting from momentum.
You could also do V-ups, where you keep your legs straight and reach your arms and legs up at the same time trying to touch your toes. You can do decline sit-ups where your legs are elevated above your torso. Or, you can add weight to your sit-ups by holding weights or a medicine ball.
These are advanced versions, 100 reps of which should only be attempted by the very fit. If you can do these versions, you're burning a lot more energy.
As Part of a Complete Workout
The best way to get a lot of bang for your buck is to incorporate 100 sit-ups into a circuit calisthenics workout. Choose several exercises, such as push-ups, squats and pull-ups and rotate from one exercise to the next in quick succession. You can break up the sit-ups into blocks of 20 or 50, or do them all at once at the end of your workout.
Moving quickly without rest breaks will get your heart rate up and keep it there, which is how you burn the most calories.