Progressive overload is the catch phrase that refers to adding additional training stimulus over time. From a given training stimulus, you can increase it a few ways, some of which lend themselves to different goals:

- Increase the weight
- Increase the repetitions per set
- Increase the number of sets
- Decrease the rest period

Doing any of these, or a combination of these, can increase the training stimulus so that you encourage additional growth. There's plenty to read out there about the difference between training for strength and training for muscle growth, but there may be a case to be made for balancing both of these goals.

In very rough, non-technical terms:

- Strength means your central nervous system is better at firing off more muscle fibers--maybe more intensely. Training for strength in this sense is normally done using lower repetitions per set.
- Muscle growth means the muscle fibers are bigger. They are usually able to move heavier weight than they used to as a result of being larger. Training for muscle growth is normally done using higher repetitions per set.

These are different strategies for training your muscles, and the divergence between them may or may not admit to synergies in their combination. Or, maybe it just doesn't suck too bad to mix it up a bit. I don't know. I'm not sure anybody really does. But I thought it would be interesting to use calculated 1 rep maxes as an index for the purpose of choosing a combination of weight and rep changes that results in a kind of theoretical progressive overload. I don't imagine I'm doing anything new, but hopefully, the spreadsheet I cooked up can make it easy enough for you to apply in your own training, if you don't think it's crazy.

Estimated 1 rep maxes are based on charts like this one: https://strengthlevel.com/one-rep-max-calculator. The idea is, if I do shoulder press with 95 lbs and I can do 12 reps before failure, I want to know how much weight I could do shoulder press with 1 time. According the chart I linked to, if I can do 12 reps with a given weight, that weight is 71% of my 1 rep max. So, if I divide 95 by 0.71, I am looking at my calculated 1 rep max. So, as long as you have a good chart of percentages, your calculation is pretty easy and is easily done in a spreadsheet using a look up or index function. I nabbed the percentages from my FitNotes app and am using them in my spreadsheet.

Estimated 1 rep maxes are based on charts like this one: https://strengthlevel.com/one-rep-max-calculator. The idea is, if I do shoulder press with 95 lbs and I can do 12 reps before failure, I want to know how much weight I could do shoulder press with 1 time. According the chart I linked to, if I can do 12 reps with a given weight, that weight is 71% of my 1 rep max. So, if I divide 95 by 0.71, I am looking at my calculated 1 rep max. So, as long as you have a good chart of percentages, your calculation is pretty easy and is easily done in a spreadsheet using a look up or index function. I nabbed the percentages from my FitNotes app and am using them in my spreadsheet.

Reps |
% of 1 Rep Max |

1 | 100 |

2 | 97 |

3 | 94.5 |

4 | 91.5 |

5 | 89 |

6 | 86 |

7 | 83.5 |

8 | 80.5 |

9 | 78 |

10 | 75 |

11 | 73 |

12 | 71.5 |

13 | 69.5 |

14 | 68 |

15 | 66.5 |

Using this chart on a sheet named '1 rep max percentages', I use the index function to drive a calculation. Along the left hand side I have the weight that is lifted and along the top I have the number of repetitions. To interpret the chart, look on the left hand side for the weight you lifted and find the column that corresponds to the number of repetitions you did. The number at that intersection is your estimated 1 rep max--provided the percentages driving the spreadsheet are legit. If you come across a chart you think is better, you can edit the values in that table and that will be reflected in the estimated 1 rep max.

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- Look up table: '1 rep max percentages'!$A$2:$B$16
- Index (row) of table: B$1
- Column of table: 2

The $ signs are a way of saying to Excel, "when you copy me to another cell, don't change me, keep me the same." So, the parts of the cell references that don't have a $ sign in front of them change when you copy them (relative copy), but the $ sign parts do not (absolute copy). The table of percentages is fixed with the $ signs and the row number (B$1) is fixed so that when you copy the cell down, it still looks to the first row for the number or reps. 2 is the column of the percentage table we need to feed into the formula. The table is pretty easy to make.

Here are links to the spreadsheet in Excel format and a print out to PDF, if you can't be bothered making the spreadsheet yourself.

Progressive Overload

Using the chart to help you with progressive overload is probably pretty obvious, but it maybe deserves some brief comments. Suppose you are doing an exercise with 155 lbs with 3 sets of 12 repetitions. 12 reps is not actually the most you can do in one set, but we don't care about your real 1 rep max. It's just an index. The fact that the index is used sometimes for calculating 1 rep maxes doesn't matter to us. It is just a way of guessing at a progression. We don't care that it isn't a "real 1 rep max", we only care that by interpreting this calculation as an index, we can use it to provide guidance for switching up our weight and reps at the same time.

It's just a number.

But it's a number that can help you.

Figure 1 shows some highlights of a way forward from 3 sets of 12 reps with 155 lbs to gradually move toward lower reps and higher weight while (hopefully) targeting an effectively greater stimulus. After you manage a full 3 sets of 12 reps, on your next workout after that, try for 3 sets of 10 with 165 lbs. In theory, if you achieve that, you have improved your strength (in some sense). If you don't succeed, you try again next work out, until you do succeed. Your next target could be 3 sets of 9 with 175 lbs.

Fig 1. Highlights show a possible path of progression. |

To the extent that this method of indexing the effective training stimulus may be valid, it can be used in a variety of ways. If you have been lifting very heavy, low reps, and you want to provide your tendons with a break or just change things up and lift light for fun, you can use this chart to help you decide what your target should be.

It's important to note though, that if you significantly change the number of reps per set, it will have a potentially large impact on your accumulated fatigue from set to set. My own experience suggests to me that with high repetition work, I accumulate a high amount of fatigue and with lower repetition work there is less of a fatigue angle involved. This confounds the matter when you make a large change to the number of reps and it probably comes apart at the seams a bit. These numbers may still help you get in the ball park.