Sudden drop in training load

I have the same issue. I'm very dissapointed not to see a response from Garmin after a year.

I've been slowly building up my training load over the past couple of weeks. Had a hard training day yesterday but not excessive, got the load up to 265.

Today its dropped all the way to 145. I can feel it in my body I need more time to rest but according to Garmin if I don't train today I risk dropping out of optimal range.

Seems like you had a hard training day 7 days before, which has now been substracted. So the load seems correct

Hi Jfox, 

Thanks for the reply. I did have a bit of a long session 7 days before although it didn't increase my training load by that much at the time. 20 points or so. 

I guess that must be the cause although I don't understand how Garmin calculates this in the background. And why that would cause a 120 point drop. 

There is not really much calculation, everyday at midnight the load you had in the training from the 7th day prior to that gets substracted…

I've noticed the same issue since I started seriously following Training Load to try to manage the risk of overtraining in transition seasons to different sports. My graphs look a lot like yours. I'll get a fairly gradual buildup to good TL's, then sudden crashes of up to 200 units even on days with strong workouts. At first I thought it was the 7 day dropoff issue (which I'd encourage Garmin to make more physiologically realistic), but no, frequently I have no corresponding big workout 7 days previous. You can see a good example in the recent big drop below-- 7 days before is a steady high reading, and the big drop occurs on a day with a 3 hour mountain hike scoring a TE of 3.1. I do have to hike hard in rough terrain to get a good TE because the watch thinks I'm trail running very slowly despite the high heart rate. Does seem like there's something odd going on here with the TL though. It basically makes an elegant and promising metric unhelpful.

One potential cause I'm vaguely wondering about: I don't actually run too much, so I have copied custom activities for my main sports-- WW kayaking, XC skiing, hiking, climbing, mountaineering, and so forth. All these sports have intense effort and high HR a lot, but differ substantially from average runs in that speeds can often be very high without high HR or cadence, or durations very long (10+ hours) with very slow speed but high effort per km. I wonder how the history in the watch might cope-- it would seem in the former case one would appear to have superhuman fitness and in the latter the opposite.

Your first drop could be explained by the 7-day cutoff, but not the second one. I get these too, where after significantly more than a week of steady and climbing TL there's a sudden unexplained huge drop. Maybe it's a bug-- this kind of drop just doesn't make sense if the TL is only the sum of the past 7 days training effort scores. It reminds me a little of the random giant drops in hydration status that often happen on synching between phone and watch. Wonder if there's a similar synch error problem here?

You cannot judge it from the 7day load, you need to look at the loads off the single exercises to be able to calculate correctly. If you have an edge 530 or similar you can see this like in the picture below, but unfortunately with the 245 you will not see the actual loads.

Below is what the FR245 gives. I'd assumed the single digit vertical scale was x100 to get TL, but that seems too high. So the different colours on your bars are different exercises on the same day, or are they different components like slow aerobic, threshold aerobic, and anaerobic?

1. The 245 gives you only the training effect from which you cannot directly calculate the actual load. Exactly, grey is an recovery exercise, green low and orange high aerobic.