Sit-up
Videos
The sit-up is an abdominal endurance training exercise to strengthen, tighten and tone the abdominal muscles. It is similar to the curl-up, but sit-ups have a fuller range of motion and condition addi
Sit-up form
Seabees conduct a situp variation
Plank (exercise)
Videos
The plank is an isometric core strength exercise that involves maintaining a position similar to a push-up.
Sit-up
…branch of the U.S. armed forces have begun to phase out sit-ups and crunches, due to the high rates of lower-back injury. They have been replaced by planks. Crunch (exercise…
Recruit performing a plank at a US Coast Guard training
Extended plank
Side plank step by step
Modified side plank