The fitness score of a run activity is much lower than a cycling activity.

[lester98]

I do both running activity and cycling activity. Sometimes my main activity is cycling such as in 2022, and sometimes my main activity is running such as in 2023 and 2024, however, the fitness score have big difference, which confused me.

Let me select two activities as example:

(1) Cycling:

https://www.strava.com/activities/9908361946/

https://www.strava.com/activities/9912507863

Training impulse in fitness page is 163 (sum of two activities in one day)

AVG heart rate （143bpm@54min + 119bpm@70min）

(2) Running

https://www.strava.com/activities/10693391953

Training impulse in fitness page is 163

AVG heart rate 152@94min

The physical intensity of The Running activity(2) is a little higher than the two cycling activities(1), however, the fitness score of running activity is less than 25% of cycling activity.

So when I mainly do cycling activity, the fitness level is easily reach 30+, and when I mainly do running activity, the fitness level is less than 10 even if I train hard.

Could support team check the algorithm and make the fitness score similar between a cycling activity and a running activity with similar physical intensity?

Thank you!

[Jane]

Hello @JannieHeath 

Thanks for your post.  It looks like you made some changes to your Heart rate zones on Strava between those two rides, which is why you're noticing that discrepancy.  Relative effort is calculated by looking at how much time you spend in each heart rate zone, with higher points given to higher zones.  

More information on Strava's relative effort score is here

[JannieHeath]

Hi @Jane 

Thank you very much for the quick response. I did not realize that my Heart rate zones affect the Relative effort and then also that affects the fitness curves. Can I change the heart rate zone and then upload or sync all the activities from December 2023? 

Thanks, Jannie

[Jane]

Hi again @JannieHeath 

Are you asking about updating the relative effort on previous activities to reflect the new heart rate zones?  That's possible - Strava Support can run a job on your account to recalculate all relative effort based on current heart rate zones.  

If you want that done, please submit a support ticket and someone from Strava Support will be happy to help you out with that.

[Scout · Accepted solution]

Follow up from our support team: There are two ways to calculate an activity's effect on Fitness.
        Relative Effort

• This is calculated by taking your Heart Rate data and seeing how it corresponds with your Heart Rate Zones
• You can also set a Perceived Exertion on your activity if you don't want to use heart rate zones 
  Power
• Training Impulse from Power data is calculated by taking your Power data and seeing how it corresponds to your Power Zones

If an activity has both Relative Effort and Power available, the Fitness impact will be based on Power and not Relative Effort.
 
From the Strava website, however, you have the option to filter your Fitness & Freshness score based on only Power or only Relative Effort.
 
In this case, the Ride activities have both Power Data and Relative Effort so the effect Fitness will be based on the Power Data and the Power zones.

[Jane]

Hello @lester98 

Thanks for posting about this.  There can be a lot of different factors that influence fitness scores.  For example I notice on your rides you are recording power data and heart rate, while runs just have heart rate data.  

I've escalated this to a support ticket, so someone from our support Team can have a close look at your activities and settings and provided more information.  Thanks.

[JannieHeath]

Hi @Jane 

Thank you for your reply to @lester98  post. 

I seem to be having the same issue, and it was never the case. Here I went on an identical ride, one with a 39 relative effort and one with a 301 relative effort. One of my friends that was on the same ride had a 204 relative effort while mine was 39. I have bee trying to fix this, but have not been able to. I can get the relative effort up if I do not use my HR data, bit that does not seem accurate.

Here are the two rides.

• https://www.strava.com/activities/11067568693
• https://www.strava.com/activities/3711234473

I would appreciate your help, as currently I can not rely om by Strava data.

Thanks, Jannie