I pay pretty close attention now days, but your warning is a good reminder. I stopped doing situps a long time ago, and stick with crunches, as situps were just

I pay pretty close attention now days, but your warning is a good reminder. I stopped doing situps a long time ago, and stick with crunches, as situps were just uncomfortable. I think a general "pay attention to your body's warning signs" is a good common sense rule.