What are the different types of sit-ups?

There are literally dozens of different core exercises that can be classified as sit-ups. These include crunches, chinnies, jack-knife, straight-leg, weighted and Swiss-ball sit-ups, plus Russian twists. According to Muscle Prodigy, Janda-style, V-type and commando sit-ups are the most effective type of sit-ups to workout the abs.

Muscle Prodigy explains that the three variations are considerably different from their conventional counterparts; therefore, each is more effective. For example, the Janda-style sit-up requires the athlete to pull his upper-body downwards on an inclined bench against the resisting force of a companion while the lower legs and glutes remain fixed in place. This keeps the focus on the abdominal muscles and discourages the contraction of the hip-flexors, which assist in conventional sit-up variations.