It has been discussed for a long time, sit-ups may be the culprit to many of our seasoned exercisers. Heck in the 70's, 80's and 90's, we crunched-we performed hundreds of crunches. We hung from bars and crunched! We placed heavy weights on our chests, behind our neck, and in between our feet...You know what I'm talking about...you know who you are...Even today you want to believe crunches and sit-ups are needed for core strength and definition.
Well finally we know that sit-ups and crunches impose extreme compression force on the discs and vertebrae of the spine, especially the lower back. Crunches also have been known to create strain and stress on the neck or cervical spine if not kept in a neutral position during the movement.
The US Army is phasing out sit-ups from the Army Physical Fitness Test as well in their training programs.