You don’t buy a prescription, you buy the stimulus.
When you get a paracetamol, you don’t care that it’s 500mg, you want your headache gone.
So with a workout, we’re not looking to Rx (unless we’re competing), we’re looking for a particular stimulus.
We’re looking for something that’s “heavy” for us one day, and that could mean building pure strength, strength endurance, power endurance. Your coach will give you guidelines along the lines of “this should take you about 1-2 minutes to get through your first set”, “we’re looking for sets of 3-5 touch and go reps” or one of our favourites “we’re looking for an ‘oh fuck’ weight” (That’s a weight you lift and causes you to step back, muttering “oh fuck” to yourself.
Sometimes we’re looking for constant movement for a period of time, or the workout to be done in 8-10 minutes, or it to be an all out sprint.
The “Rx” (prescribed) weights then are a guideline to help you understand what weight to use, and then with your coach we decide what will give you the best workouts for your goals and development.