Hi Hoosegow. I'll use the heavy day as an example where you "pyramid " up using 5's to 1 to 2 top all out worksets. I'm going to plagirize Bill Starr from his book "The Strongest Sall Survive - Strength Training for Football". He explains it like this. The first three progressively heavier worksets (starting from around 50% or so) let you warm up, focus on form, focus on speed of movement, and ease you into your top worksets. First should be easy, 2nd a little heavier but still fairly easy, the third moderately heavy, the fourth, if still a lead in should be touh but doable, if used as a top weight with the 5th set, it should your top weight of the day and very hard, the fifth, no matter what the case, should be all out. Same for the lead ins on the medium day, the difference being you only go to around 90% of your heavy day for work sets, and those should just reinforce you withouttapping too much into your recoverability. Light days, as JV Askem states them, are basically for practice, and to develope form and speed, and aid somewhat in total recovery. An interesting note that differentiates Starr and Askem though, is Starr recommends a "down", "pump" or "hypertrophy "set (depending upon who chooses the wording) of 1-2 sets of 8-10 (difficult) with a lower weight after your top work set, That's the method I prefer personally. Hope that answers it.