Sit ups are a simple yet effective workout for tightening and strengthening your core muscles without any special equipment. While a regular sit up can time your abdomen, you may have better and faster results with a weighted sit up.
You can perform a weighted sit up in the same manner as a non-weighted version. The difference is you hold a weighted plate or dumbbell in your hand.
Primary muscles activated during a sit up include the rectus abdominis which are the muscle fibers in front of the torso.
If you are looking for more definition and bigger muscles, a weighted sit up provides a new way to challenge your midsection.