Pull - up type training pants are basically diapers, with a little different design and a very clever marketing campaign. (3daypottytraining.com)
They're often called lay midwives or empirical midwives and have informal apprenticeship type training from an experienced midwife. (pregnancy-info.net)
The next two zones are primarily for those specifically undertaking endurance type training. (build-muscle-and-burn-fat.com)