Several times each month a patient comes in with a mild form of low back or SI joint pain that previously had not been there. Originally seen for some type of hip pain that had been addressed and is usually starting back to their regular exercise program.
After much probing into history, exact exercises being done, I've been able to confidently say it usually a form of standing hyper extension.
They think they are working the gluteal muscles. In reality, the glute is active from flexion to neutral. Picture climbing a very, very high step. That's the butt working. When we try to make the hip go past neutral, most (not every) people will slightly arch the back and create a lot of compression in the lumbar spine.
This is generally a way to create low back discomfort. Often times eliminating the bad stuff is all you need to stay healthy!