TSS, ATL. CTL, TSB for Heart Rate

Even though I don't have a power meter I found a lot of the training concepts explained in "Training and Racing with a Power Meter" pretty interesting. One of the things power users can do is graph a variety of statistics about the types of riding they are doing to help manage their work load. I won't be able to capture this sort of data for every pedal stroke but using my heart rate should still be able to give me some interesting information.

Here are some of the stats power users are keeping track of.

IF (Intensity Factor)

Intensity factor represents how hard you are riding. 1 equals your threshold. Here is a basic outline for IF that comes with the TrainingPeaks software:

• Less than 0.75 recovery rides
• .75-0.85 endurance-paced training rides
• .85-0.95 tempo rides, aerobic and anaerobic interval workouts (work and rest periods combined), longer (>2.5 h) road races
• .95-1.05 lactate threshold intervals (work period only), shorter (<2.5 tss =" IF^2">

TSS (Training Stress Score)

Training stress score represents how hard a workout is. Once you figure out the Intensity Factor of your ride you can figure out your Training Stress Score.

The formula for this is:

TSS = IF^2 x hrs x 100

So here's how I would calculate my TSS for a typical 2x20 workout.

The workout is a 10 minute warm up followed by 20 minutes at threshold, 5 minute recovery, 20 minutes at threshold, and 5 minutes cool down.

First, we need to figure out the Intensity Factor for the different pieces of the ride. We'll assign .75 for the recovery portions, and 1 for the interval portions.

Recovery portions = .75^2*(20/60)*100 = 18
Interval portions = 1^2*(40/60)*100 = 66

TSS for the workout = 84

ATL (Acute Training Load)

Acute Training Load represents the level of work you've done over the week. It's calculated by taking an average of your TSS over the last 7 days


CTL (Chronic Training Load)

Chronic Training Load represents your current level of fitness. It's calculated by taking an average of your TSS over the last 42 days.

TSB (Training Stress Balance)

Training Stress Balance represents how "fresh" you are and helps manage your peaking for key events. The formula for TSB is your CTL - ATL. When this number is positive it means that you should be "fresh" and ready for a key workout or ride.

I created a Google spreadsheet to help me calulate this stuff here

To use it you need to enter the number of minutes you spent in each "zone" for every workout you do. It will calculate TSS, ATL, CTL, and TSB for you.