Most people start an injury log the week something goes wrong. That is when memory is least reliable and the body is least calm, so the first entries tend to be vague. A preseason baseline solves that problem before it starts. It is a dated note about how you move and feel when nothing is hurting, and it gives every later entry something to be compared against.
A baseline does not need to be long. A useful one answers a handful of plain questions on the day you write it. How long did your warm-up take before you felt ready to train? Can you squat to a depth you choose without holding on to anything? Can you reach overhead on both sides, and does one side feel different? Can you stand on each leg for a steady count? How far can you run at an easy pace before your breathing or your legs change? Write the answers in your own words, not in medical terms you are guessing at.
Write Down What Is Already There
If something aches on the day you write the baseline, record it. Note the location, the activity that brings it on, and whether it is present while you are sitting still. Do not skip it because the season has not started yet. A baseline that hides an existing ache is less useful, because the first real change will look like a brand new problem when it may be an older one that has shifted.
Use the Same Conditions Each Time
Keep the conditions steady. Write the entry at a similar time of day if you can, on the same surface, and after a similar warm-up. If you test a movement on a cold morning and again after a long drive, the two notes will differ for reasons that have nothing to do with your body. Record the conditions next to the movements, even when they seem minor. Temperature, footwear, and whether you slept well are all useful context later.
Keep the Entry Short Enough to Repeat
Short entries get repeated. A long, detailed page written once is often abandoned by the third week. Aim for a few lines you can finish in under five minutes, and use the same headings every time so the entries line up side by side. A simple sheet with the date, the conditions, the movements, and a line for anything that already hurts is enough. The goal is consistency, not a complete history of your body. A record you actually keep is worth far more than an ambitious one you stop after two entries.
Read your own entries the way you would read a schedule. Look for what stayed the same, what moved, and what you simply stopped testing. Skipping a movement is also information. If you quietly stopped reaching overhead and never wrote down why, that belongs in the next entry.
Why the Record Helps Later
When a new ache shows up in the middle of a season, the baseline answers a question memory cannot answer well: what changed, and when? If your overhead reach looked even on both sides in August and uneven in October, that is a concrete detail you can bring to an examiner. Without the baseline, the same ache comes with a guess about when it started. A dated comparison is easier to discuss and easier to act on than a general sense that something feels off.
Update It, Do Not Replace It
Repeat the entry at the start of each season, after a long break, and after a change in equipment or playing surface. Keep the older entries. A baseline from two years ago describes the past, not today, but the gap between then and now is information too. Mark each new entry clearly with its date so you can see which version you are reading.
When the Log Points Toward an Exam
A baseline cannot tell you what is wrong, and a comparison is not a diagnosis. It can, however, show a pattern worth raising with a licensed examiner. Consider booking an exam if a movement you recorded as normal stays limited for several days, if an ache keeps returning at the same point in training, or if you notice swelling, numbness, tingling, or a joint that feels unstable. Bring the dated entries with you, including the baseline. If symptoms come on suddenly and feel severe, do not wait for the next log entry. Get help right away.