My assumption is that setting the "ATL contant" to 7 means that my ATL is calculated by taking the average TSS score over the last 7 days including today. Since my TSS total over the last 7 days is right at 800, I was expecting Cycling Peaks to show my ATL for today as 114, but it's not. Instead, CP says the value for today is 91.
I'm obviously overlooking something simple here, but what am I doing wrong?
I'm obviously overlooking something simple here, but what am I doing wrong?
That's because it's an exponential moving average. Without knowing what your ATL was for any of those days, I can't give you an example using your numbers. But here is the formula for ATL assuming a time constant of 7 days:
Ahh, I get it! And--even better--it makes complete sense. Simply taking the average over the last 7 days would create misleading "timing fluctuations" such as in this example:
Day 1: 0 tss Day 2: 0 tss Day 3: 0 tss Day 4: 200 tss Day 5: 200 tss Day 6: 0 tss Day 7: 200 tss Day 8: 0 tss Day 9: 0 tss
If it were simply an average rather than a moving average then the ATL value on days 7 through 9 would be the same which obviously doesn't make sense.
