What swimmers track in Baseline
Swimming is traditionally the most data-poor of the three main triathlon sports, but modern swim trackers - Garmin watches, Apple Watch Ultra, Coros Pace Pro, Suunto, and smart goggles like FORM - capture a surprising amount of information: pace per 100m, stroke count, SWOLF efficiency, stroke rate, Critical Swim Speed (CSS), and for open-water swims, full GPS tracks. Baseline surfaces these metrics alongside your cycling and running data, so you can see whether that CSS improvement is translating to faster bike-run transitions, and how your swim training load contributes to your overall fatigue. For triathletes, swimming has an outsized impact on perceived fatigue - Baseline shows you the actual data.
Sport-specific KPIs we surface
Critical Swim Speed (CSS). CSS is swimming's equivalent of FTP or lactate threshold pace - the maximum pace you can sustain continuously. Baseline estimates your CSS from your best 400m and 200m times, plots it over time, and tracks whether your aerobic swimming fitness is improving. CSS trends are the definitive measure of swim endurance progress.
SWOLF (stroke efficiency). SWOLF combines stroke count and time per length into a single efficiency score. Lower SWOLF means better efficiency - you're covering more distance per stroke with less energy. Baseline tracks SWOLF trends over weeks and months, correlated with swim volume and intensity changes. A SWOLF that decreases while pace holds steady means your technique is improving.
Stroke rate and stroke count. Baseline surfaces your strokes per minute and strokes per length trends. A stroke rate that decreases at the same pace suggests improved distance per stroke. A stroke count that varies between the start and end of a session might indicate technique breakdown under fatigue.
Pace per 100m trends. Pace per 100m is the most swimmer-familiar metric. Baseline tracks your average pace per 100m across all workouts, broken down by effort level and session type. Pace trends in threshold sets vs warm-up sets reveal different aspects of fitness.
Pool vs open-water comparison. Open-water swimming is physiologically different from pool swimming - no walls, no lane lines, variable conditions. Baseline separates your pool and open-water data, comparing pace, stroke metrics, and heart rate across environments. If your open-water pace drops significantly relative to pool pace, there's a specific skill to work on.
Heart rate and rate of perceived effort correlation. For heart-rate-equipped swims, Baseline correlates your swim pace with heart rate to estimate efficiency. A pace that improves at the same heart rate means better swimming efficiency. A heart rate that drops for the same pace means improved cardiovascular fitness. This relationship is especially useful for swimmers moving from pool to open water, where environmental factors add variability.
Recommended integrations for swimmers
- Strava: Most swimmers who record their workouts use a Garmin or Apple Watch that syncs to Strava. Connect Strava to Baseline for automatic import of every swim - pool sets with lap breakdowns, open-water GPS tracks with stroke rate, heart rate across intervals, and drill detection data.
- Apple Health: If you swim with an Apple Watch, the Apple Health zip import brings in swim workouts with stroke detection, lap counts, and heart rate. The Apple Health export also includes any open-water swim GPS routes recorded by your Watch.
- Garmin: Garmin Forerunner and Fenix watches offer the richest swim tracking - drill logging, rest detection, critical swim speed estimation, and open-water GPS. The planned Garmin integration will bring all of these into Baseline.
- WHOOP: Swim recovery is heavily influenced by sleep quality and HRV. Connect WHOOP to see whether your CSS improvements correlate with better recovery, or whether hard swim blocks are producing more fatigue than your training load model predicts.
Pricing tease
Baseline is free to start with no credit card required. The free tier includes your dashboard with one connected source and basic swim metric tracking. Upgrade to Baseline Pro for $12/month (or $249 lifetime) to unlock unlimited integrations, AI-powered daily insights that correlate your swim performance with recovery and sleep, the full-resolution heatmap including open-water swim routes, geographic coverage stats for open-water swim locations, and the achievement system including swim-specific badges for distance and consistency milestones. No ads, no data sharing.