May 30, 2026 · 6 min read

How to Analyze a Ride File? 5 Things You Must Look At

Analyzing a ride file comes down to five checks: interval execution against the plan, Normalized Power and Intensity Factor, time distribution across power zones, heart rate divergence relative to power, and new records on the power curve. Five minutes after the workout is enough to know whether the session did its job — and whether your body handled it the way it should.

1. Did you do what the plan said?

Start by comparing execution with intent. The plan said: 4×8 minutes at 260 W (95% of FTP) with 4-minute recoveries. The file says: 262 W, 258 W, 251 W, 239 W. The first three repeats — fine; the fourth dropped 8%, and that's information: either the zone was set too high, or you started the session under-recovered. A power fade of more than 5–7% between the first and last repeat of a threshold workout is a signal to start 5–10 W lower next time.

How do I check whether an interval was executed correctly?

Compare each repeat's average power to the target: a deviation within ±3% and a fade below 5% mean a well-executed workout; a bigger spread points to wrong zones, fatigue or a pacing problem.

2. NP and IF — what this ride really cost

Average power lies when the ride is punchy: a 165 W average from a group ride with sprints can correspond to a Normalized Power of 210 W. So look at NP and the Intensity Factor (NP ÷ FTP). An IF of 0.65–0.75 is an easy ride, 0.85–0.95 — a solid threshold session, and an IF above 1.0 on a ride longer than an hour usually means your FTP is set too low. How exactly this metric is computed, we covered in the piece on weighted average power (WAP/NP).

3. Time in zones — did the workout have the right color

The time-in-zone distribution verifies the session's character. A Z2 ride should by design have 80–90% of time in Zone 2 — if you see 25% in Zone 3, that wasn't an aerobic ride but the "grey zone": too hard to build the base cheaply, too easy to provide a threshold stimulus. The classic amateur mistake. The reference point here is a correctly established FTP and power zones — without that, the whole analysis hangs in mid-air.

How much time in Zone 2 should a base ride have?

At least 80% of ride time in Zone 2 (56–75% of FTP); if more than 15–20% leaks into Zone 3, ease off — the aerobic stimulus stays similar while the recovery cost drops noticeably.

4. Heart rate against power — the cheapest fatigue detector

Overlay the heart rate trace on the power trace. Two things matter. First, drift — if at a steady 200 W your pulse climbs from 140 to 155 BPM in the second hour, you're looking at dehydration, heat or gaps in your aerobic base (details in our article on cardiac drift). Second, the level — a heart rate 8–10 BPM lower than usual at the same power, combined with heavy legs, is a common symptom of overreaching. Same power, different pulse — that's always a "why?" question.

5. The power curve — did any records fall

Finally, a glance at the power curve: did today's ride set new maximums at 5 s, 1 min, 5 min or 20 min? A new 5-minute record (say 310 W instead of 298 W) in the middle of a VO2max block is hard confirmation the training works. No records at all for 6–8 weeks despite regular training — a signal to change the stimulus. What the individual points of the curve say about you, you'll find in our separate guide to the power curve.

How often should I analyze my ride files?

A short check (2–5 minutes) after every workout and a weekly review every Sunday — a single file speaks to execution; only the sum of weeks on the PMC chart speaks to form.

Summary

Five checks — execution vs plan, NP/IF, zones, heart rate vs power, records — turn a raw FIT file into training decisions: adjust the zones, add recovery, or change the stimulus. A single workout is still just one data point, though; before drawing conclusions about your form, set it against the last weeks' load on the PMC chart.

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