Endurance score drops 500 point

I would like to understand endurance score better too. I think it is based on some rolling period, for example 12 weeks. What might be happening is that some large activity that you had 12 weeks ago may now be coming out of the scope of endurance score, and that makes it drop.

I've seen similar examples myself, typically on Saturdays or Sundays when I tend to do much longer runs. Sometimes I do a fairly large effort and yet my endurance score drops. That's is probably because I did an even larger effort a number of weeks ago, and that is no longer included in the calculation of the score.

I think that points to a bad design of endurance score calculation. Ideally it should be weighted so that more recent activities have a larger weight and over time the weight drops. But it doesn't appear to work that way.

Garmin-Laurie, I've seen this article before and read at least 3 times in the past. Maybe it is just me but it explains almost nothing. For example it doesn't explain why endurance score can go down after a long and hard effort that is clearly far above average. For example I can do a few short runs during a week and my score doesn't move much or even increases. Then I do a long and hard effort on the weekend, and the score drops. That is frustrating!

Then there is the following situation that I observed a couple of times. Imagine that you do a very hard ultramarathon race, let's say a 100 miler. After such a race there is usually a few weeks of recovery. It is reasonable for the endurance score to drop during that period. But then it remains flat or even continues down for another 2 months despite significantly ramping up the volume and the effort. I think the main reason is that the training runs that were done before the race keep going out of scope and that makes the score drop despite all the effort to move it up. 

A better implementation of the score would show me all the activities that are considered for the score and how much each of them impacts the score. Then it would be much more actionable. But when it gives me the recommendation to increase duration and difficulty of my long runs when I already do that, and my score keeps going down, that is discouraging!

I had the same experience as you.

I train mostly for cycling (MTB/BDC) + running

In June I had an endurance score of 7800. One of those mornings (June) I went for a 240km and 5000m (16404 ft) ride and came back home in the evening with a lot of energy.

In July (very hot) I stopped running, but I did another nice ride of 200km and 2500m, then I reduced the activities and for a couple of weeks I saw my endurance score go down.

I started running again and I was tired after 10km. In June I could run for 21km in trailrun with a lot of energy. The other day I did 8km of Trail Running and I also fell (I was tired). So, for my case, I find the reduced score correct because I don't have the same resistance that I had in June/July and even on the bike (where I am much more prepared) I wouldn't do a 200km ride with my current conditions (tiredness).

The endurance score is not like the VO2MAX (the latter dropped by 1 point), it can vary a lot if the training load decreases (in my case it is almost half compared to June).

My score took a nose dive of 500 points this week when I went for a trail run rather than my usual Peloton ride. 500 points literally after one different activity!! Crazy!!

I’ve built up my fitness on a Peloton over the last few months. Up until a few days ago, my score was over 6600 and steadily increasing nicely every day. I went away for a few days with no access to a bike, so I did a trail run. 8km, moderate elevation. My endurance score fell off a cliff!! 500 points lost!! 

This can’t be right surely?!?

My entire endurance score has been built on indoor riding. I haven’t run much recently, but on the occasion I have, my endurance score has increased so I was expecting the same this time, except after the most recent runs, the score plummeted. 

• And with software 18.14 the bad behaviour is not fixed. My endurance score went down after a 17 km trail run. I don't know how many 60 years old people can run 17Km, but I do know that my endurance has increased. Three days later I trail ran another 10K. So the watch calculation is not matching the reality. Regarding my training load, after a week of 30K trail runnig this says Low. So to keep a high training load I must run 100K per week at 60 years old? Just crazy! The software updates are bringing new features, but destroying the good functionality I was having when I purchased the watch.