Post-Race .FIT File Auditing

Your watch records every second of your race in a data file. After the race, this file shows exactly how well you paced: not how it felt, but what really happened. Pacer Academy uses it to calculate a few simple numbers that tell you how close you were to the plan and how steady you were. You do not need to be good at maths. You only need to understand what each number means.

Step 1: Export and submit your file#

Most watches save the run in a .FIT file (the original file the watch records). Some apps can also give you a .GPX file, which mainly contains the GPS track. The .FIT file holds more detail, so use it when you can.

1. Sync your watch with its app (Garmin Connect or COROS) after the race.
2. Open the race activity. Use the app's or website's export option to download the original file (.FIT) or a .GPX file.
3. Submit the file to your pacer group within 24 hours, as the Pacer Support Guide asks (see After the race). Submit it even if you had to stop pacing.
4. Upload the same file to the Accuracy analyzer together with your target split plan.

Step 2: Understand the three numbers#

MAE (Mean Absolute Error) answers: "On average, how many seconds was each split away from the target?" Fast and slow errors both count, so they cannot cancel each other out.

σ (sigma, the standard deviation) answers: "How jumpy were my splits?" A low σ means smooth, steady running. A high σ means surging and slowing.

PCS (Pacing Consistency Score) combines both into one score out of 100. It gives 60% weight to being on target (MAE) and 40% to being steady (σ), compares this with your target pace, and subtracts the result from 100:

PCS = 100 − (MAE × 0.6 + σ × 0.4) ÷ target pace per km × 100 (and never below 0)

A PCS of 99 means your errors were only about 1% of your pace. A PCS of 90 means about 10%.

Worked example#

A 5 km run with a target of 300 s/km (5:00 min/km). The actual splits were 298, 302, 305, 295 and 301 seconds.

The average was almost perfect, but each kilometre was on average 3 seconds off target. That is still an excellent score.

Step 3: Read your rating#

The analyzer also shows your finish error: your actual finish time minus your target finish time. A positive number means you were late, a negative number means you were early. A great PCS with a large finish error usually means you were steady but steady at the wrong pace, so check your plan and your GPS over-distance margin.

For CDPP Level 3 (Lead Pacer) you need a PCS of at least 95, and the practical test asks you to hold a 5 km run within ±3 s/km of the assigned pace, checked with your .FIT file.

Key takeaways#

• Export the .FIT (or .GPX) file and submit it within 24 hours, even if you stopped early.
• MAE shows how far off target you were; σ shows how steady you were.
• PCS combines both into one score; 98 or more is Excellent.
• Finish error shows whether you were early or late overall.
• Use the per-split chart to choose what to work on next.