This is 8:00 of continuous swimming with 1:00 rest. Each time there are slightly different instructions. “Deep” refers to deep practice, where I ask our swimmers to focus on one technical element and try to improve it. On #4, they swim continuous backstroke until they hear me bang the wrench on the side of the pool. When they hear the bangs, they sprint br 2 walls (25-50m) and then return to swimming steady backstroke.