Does Strava have a Running Index equivalent?
Not directly. Strava Fitness and Relative Effort focus on accumulated training load and cardiovascular work, not speed relative to heart-rate effort.
A Running fitness metric from the data you already have
Looking for a Polar Running Index style metric in Strava or Garmin?
Strava Fitness tells you how training load is building. Polar Running Index and COROS Running Fitness ask a different question: are you running faster for the cardiovascular effort? RunFit brings that kind of pace-versus-heart-rate trend to compatible runs already in Strava.
Does Garmin have something similar?
Garmin Running Economy measures aerobic energy cost. It uses heart rate, speed and running dynamics and currently requires compatible Garmin hardware plus an HRM 600.
Can I track this from my Strava runs?
If your running activities include usable heart rate and speed data, RunFit can calculate a simple fitness index trend and compare it with a race-goal reference.
Quick comparison
These metrics sound similar, but they answer different questions
The numbers are not interchangeable. The useful comparison is what each metric is trying to tell you.
| Metric | What it tells you | What it uses | Direction |
|---|---|---|---|
| Strava FitnessTraining-load metric | How your accumulated training is changing over time | Relative Effort and/or Training Load | Higher = more accumulated fitness/load |
| Polar Running IndexRunning-performance metric | How aerobic running performance is changing | Heart rate + running speed | Higher is better |
| COROS Running FitnessPerformance model | How running performance is changing | Pace/heart-rate relationship + COROS modelling | Higher is better |
| Garmin Running EconomyAerobic-efficiency metric | How much aerobic energy is needed to cover distance | Heart rate + speed + running dynamics | Lower is better |
| RunFit IndexTransparent fitness index | Are you producing more speed for the same relative heart-rate effort? | Speed + heart rate as % of max HR | Higher is better |
Different platforms use different algorithms, assumptions and inputs. Their numeric scores should not be compared directly.
What RFI adds to a Strava training history
One score is useful. The trend is the part that matters.
RunFit is designed around following your own running fitness and efficiency over time rather than judging a single workout in isolation.
See the trend over time
Plot calculable runs across recent months or your longer locally stored history and see whether fitness is moving up, down or sideways.
Keep workout types meaningful
Easy, steady and interval sessions remain identifiable, with interval handling designed to reduce distortion from short reps and heart-rate lag.
Track progress toward a race goal
Set a target distance, finish time and expected race heart rate. RFI converts that into a reference line and shows how your smoothed trend is progressing toward it.
Simple on purpose
A transparent running-fitness metric
RFI is intentionally narrower than a full training-readiness or race-prediction model. It asks one understandable question: how much speed are you producing for your relative cardiovascular effort?
If you record with Garmin, Apple Watch, COROS, Polar or another device and the resulting activity reaches Strava with usable heart-rate and speed data, the recording brand itself is not the important part.
RunFit Index
RFI = 400 × speed ÷ HR % max
Higher means more speed for the same relative heart-rate effort.
FAQ
Common questions
Is RunFit Index the same as Polar Running Index?
No. They use related inputs and both are intended to reflect running performance, but Polar's algorithm is proprietary and includes its own modelling. RunFit Index uses a simple visible formula and should be treated as a separate but related metric.
Is RunFit Index the same as Garmin Running Economy?
No. Garmin Running Economy estimates energy cost in ml/kg/km and incorporates running dynamics. RunFit Index is based on speed relative to percentage of maximum heart rate.
Is Strava Fitness a running-efficiency score?
No. Strava describes Fitness as a score based on Relative Effort and/or Training Load that tracks accumulated training over time. It is useful, but it measures something different from pace-versus-heart-rate efficiency.
Do I need a Polar, COROS or Garmin watch to use RunFit?
No specific watch brand is required. The app works from compatible running data available through Strava, including heart-rate and speed data.
Can I use Garmin-recorded runs?
Yes, if those activities have synced to Strava and include the data RFI needs. RunFit calculates its own score from the Strava activity rather than relying on a Garmin-specific fitness score.
Does the race-goal line predict my race result?
No. It is a training reference based on your selected distance, target finish time and expected race heart-rate percentage. Race performance also depends on endurance, course profile, weather, fueling, pacing and other factors.
Official references:
Strava Fitness
Strava Relative Effort
Polar Running Index
COROS Running Fitness
Garmin Running Economy