"His own studies have demonstrated that repeated bending of the spine, as happens when we do crunches, can damage spinal discs over time."
Uh-oh. I probably do 17,000 flip turns a year. Guess I'm in big trouble.
"His own studies have demonstrated that repeated bending of the spine, as happens when we do crunches, can damage spinal discs over time."
Uh-oh. I probably do 17,000 flip turns a year. Guess I'm in big trouble.
