'Intensity' + 'Training Load' relating to Workouts

The terms 'Intensity' + 'Training Load' relating to Workouts, either as you are writing up in Workout Creation or as you perform a workout, what do they relate to, measure, or Algorithm utilised to achieve these numbers.
How do they relate to familiar terms such as "Intensity Factor" + other Training Peak/WKO or Stress Score numbers used in exercise physiology?
AA
How do they relate to familiar terms such as "Intensity Factor" + other Training Peak/WKO or Stress Score numbers used in exercise physiology?
AA