Hi Deb. Thank you for the feedback and question. As a coach, I use 1-2 stroke range over 25m, and 3-4 stokes over 50m. But with swimmers, would add a stroke to each range. We design a range of sets, but many hinge around sets to encourage holding SPL consistency as tempo increases. Depends on the set, the outcome you want to achieve and the level of conditioning at any one point in time. The trick is to find the tempo you 'drop a stroke' - likened to changing gears in the car!! This is the inflection point.... work your sets around that tempo - playing with tempo, reps, sets, rest variables to 'condition' your neuro-muscular and metabolic systems..... and limit that dropped stroke, push it out to a faster tempo. Remember, any increase in power output to overcome increased drag comes with an 'energy cost'. Some of the other vids allude to the set structure