The short answer
For each exercise, write down the weight and the repetitions of every working set, in the order you did them. Add the rest time or how hard the set felt if you want more detail. Before the next session, read what you did last time: that is the number to match or beat.
Why keep a workout log
Memory is unreliable from one week to the next. Without a record, you repeat the same loads, or you add weight too fast and miss reps. A log turns each session into a comparison with the previous one, which is exactly what progressive overload needs.
What to write down
The essentials: the date, the exercise and its variation, then for each working set the weight and the repetitions. Useful extras: the rest between sets, how many reps you had left in reserve, and a short note when something changed, such as a different machine, a pain or a bad night. Keep warm-up sets apart from working sets.
Log during the session, not after
Write each set right after finishing it, during your rest. At the end of the session, details are already blurred: was it 9 or 10 reps on the third set? A few seconds per set is enough if the format is always the same, for example “80 × 8, 8, 7”.
Paper, spreadsheet or app
A notebook works if you keep it with you and reread it. A spreadsheet makes totals and charts easy but is awkward to fill in between sets. An app shows last session’s numbers next to the set you are logging, times your rest and calculates volume and records for you. Choose the one you will actually use every session.
Read your log before each session
Before starting an exercise, look at your last result. If you reached the top of your rep range on every set, try a small weight increase. If not, aim for one more rep on one set. Over a few weeks, the log also shows which movements stall and when a lighter week may be useful.
Put it into practice
About this guide
STARK editorial guide. Examples explain how to use the library and record training; they are not individual coaching.
The session examples come from the STARK program catalogue linked above.