These two photos show a couple of my clients doing an exercise called spinal flexion. While it looks plain awkward it is a fairly fool-proof back developer that protects your back from all manner of injuries.
The exercise appears to be terribly bad posture and clearly displays rounding of shoulders. But in this Pilates style of exercise, the “bad posture” is EXACTLY what’s needed to prevent injuries.
It’s tough to learn but can often save people a costly trip to the chiropractor. Prevention is far better than cure.