Race comparison — side-by-side, same-format default

What it is

The race comparison page puts your finished races side by side in a table, one race per column. It surfaces splits, placement, FIT-derived per-leg stats (HR, NP, IF, TSS, pace, decoupling, W' burned, CdA), and total energy.

For each metric where "best" is well-defined — lowest split, highest power, lowest decoupling — the column holding that PR gets a PR badge on the cell.

Where to find it

• On /my-races/ — when you have 2 or more past races, the Past Races header shows a "Compare past races →" orange pill. Click it to open the comparison page filtered to your latest race's distance.
• Direct URL: /my-races/compare/?athlete_pid=...

The same-format default

Comparing a Sprint finish time against a Long-distance one is mostly noise. By default the page loads with the distance filter set to your most recent finished race's distance — so a 70.3 racer lands on a 70.3-only comparison, not a mixed muddle.

Filter chips at the top let you switch to any other distance you've raced — only distances you've actually finished show up as chips, with a count of how many races each contains. The "All" chip removes the filter.

What gets a PR badge

The platform marks the row whose value is "best" for that metric. "Best" depends on the metric:

Some metrics intentionally have no PR badge:

• Heart rate — higher isn't better, lower isn't better; it's context-dependent (heat, hydration, fitness, freshness).
• Total calories — depends on race duration and format, not a performance metric.
• Pacing verdict — "negative / even / positive" is a label, not a scalar.

A PR only appears when at least 2 races are in the filter. A single-race comparison won't show any PR badges — there's nothing to compare against.

What's sourced from where

The comparison reuses the same recap builder that powers the post-race recap card and PDF. There's a single source of truth, so a number on the comparison page will always match the number on the corresponding race's recap.

• Times + placement come from the Race row (actual_*, overall_place, age_group_place).
• Per-leg power / pace / HR / cadence come from a matched Activity (FIT file). If no FIT is uploaded for that race, those cells show "—" and the row is hidden if no race in the comparison has any value.
• CdA comes from the bike FIT via the same back-solver the CdA calculator uses (estimate_cda_from_activity).
• W' burned + match count come from the per-second power stream via the Skiba model (needs CP + W' on file for the athlete).
• Calories come from the recap energy builder.

Hiding empty stuff

To keep the page readable:

• Empty rows are hidden — if no race in the current filter recorded a value for a metric, that row doesn't render.
• Empty group cards are hidden — a "Run — FIT-derived" block with zero data for all races in the filter won't show up at all.

This means the page gets richer as you upload more FIT files and log more races.

Caveats

• IF / TSS comparability — these are normalised against your current FTP / CP on file. If your threshold has shifted between two races and you bumped MetricHistory, the older race's IF / TSS reflects the threshold at the time of the recap build (we re-fetch the latest, not the historical). Treat cross-block IF deltas as directional, not exact.
• CdA comparability — air density varies with temperature and altitude. The CdA card on each individual recap shows the density source (FIT pressure / FIT-derived from altitude / default sea-level). Two races at very different altitudes won't give cleanly comparable CdAs without that context.
• Pacing verdicts are based on first-half vs second-half averages over the full activity. A multisport FIT's bike leg is split by the child-Activity record, so the halves are within the bike, not the whole race.

What's still on the roadmap

• Cross-athlete comparison (coach-side) for teams targeting the same race
• Trend sparklines in each row showing year-over-year drift
• Goal vs actual column showing how each race did against its pre-race coach goal

See also

• Post-race recap reference
• CdA from FIT explainer
• Critical Power calculator