Write what happened
Replace bad session with observable details. Perhaps the usual repetitions were harder, the session took longer, or you stopped an exercise because something did not feel right. These statements are more useful than a single judgement about effort or motivation.
Record changes in equipment, order and rest as well. A crowded room or a different machine may explain part of the experience. If the workout itself changed, do not treat it as an exact repeat of last week's session.
Keep the entry brief enough to complete while the details are fresh. You are collecting context, not writing a report that must identify the cause before you leave.
Note whether the difficulty affected one exercise or the whole appointment. A single unfamiliar machine and a generally difficult session are different observations. Include whether anything had changed immediately before it, such as an unusual wait or a reordered sequence. These facts do not identify a medical cause, but they make the account more precise.
If you stop early, record where the session ended. A completed tick in an app can conceal the very information you later want to discuss. You can still value the decision to stop while keeping the record clear about what was and was not performed.
Add relevant circumstances
An unusually short night, a long work shift, travel or another demanding activity can belong in the note. Describe the circumstance without turning it into a diagnosis. Several things can coincide, and a training log cannot prove which one caused the change.
If you are following a coached plan, share the details and ask whether the next session should be adjusted. It is easier to discuss three clear observations than a broad statement that everything is going backwards.
Avoid testing yourself repeatedly during the same visit to see whether the day improves. Adding more work can obscure the original problem and extend a session that was already difficult.
Separate ordinary variation from a concern
One off day is different from a repeated pattern. If difficulties continue, review the programme and circumstances with an appropriate professional. Persistent unexplained tiredness, pain or other symptoms should not simply be labelled poor recovery on the basis of an app score.
Stop an activity that causes pain or symptoms that concern you and seek appropriate advice. A target in the log is not a reason to continue through a problem. Urgent symptoms require urgent medical help rather than a programme adjustment.
At the same time, do not turn every variation into a crisis. The purpose of the note is to preserve information so that a pattern can be recognised if one develops.
Leave a clear next action
A useful entry might end with ask coach about the next session or check that this was the same machine. Keep the next action within what you actually know.
When you return, read the note alongside the current circumstances. You do not need to prove that the previous day was an exception by forcing a record. Let the next suitable session add another honest entry to the history.