Training Stress Score (TSS)
Training results in stress on your body. When you are exposed to the proper amount of training stress and recovery, positive adaptations will occur.
If your workout produces too little stress, there will be no training adaptation. Too much stress or lack of recovery in and between your rides may cause injury, illness, or prolonged recovery needs. Those hard-won gains will disappear with the incorrect amount of training stress.
TSS is an estimate of stress in a workout. It is based on both intensity and duration. Cycling at 100% FTP for an hour is equivalent to 100 TSS. Training for longer than 1 hour can result in a TSS greater than 100, even if the intensity is less than FTP.
The formula used to determine TSS in your ride is:
(# of seconds of the workout x Normalized Power x Intensity Factor) / (FTP x 3600) then x 100
Our guidelines for 60 minute classes
Base Training: 55-65 TSS
Medium to hard: 65-70 TSS
Hard: 70-80 TSS
How much TSS Should I have in my Class?
Now that we have a base understanding of the concept of TSS the big question is, how do I apply this to creating my classes. It depends. The length of the class and how much variance there is in efforts both over and above FTP will be major factors.
If a rider does a quasi-steady-state effort for a full hour, the TSS for that ride would be 100. A quasi-steady state 60 minute class at 80% would result in an TSS of 80.
Compared to the above examples, any ride that is less than an hour will automatically <100 TSS. A 45-minute class done from start to finish at 100% FTP would be 75 TSS. A quasi-steady state 45 minute class at 80% would result in an TSS of 60.
The above example classes are highly unlikely to occur because indoor cycling classes are typically 45-60 minutes long, have a warm-up and a cooldown, and have varying intensity intervals that include recovery.
A general rule of thumb would be that any 60-minute indoor class would be <85 TSS and a 45-minute indoor class would be <65.
But every ride cannot be that hard. The whole concept of training is to progress intensity while being able to progressively overload all systems and get stronger over time.
As you can see, there is tremendous value in having access to the data and in understanding what that data means. As you become more comfortable with this information, you can start to see these concepts in action.
For general Based on the knowledge above, the normal profile structure for Indoor Group Cycle classes and our experience, we recommend the following guidelines for Indoor Cycling Group Training (60 minute)
Below is examples on profiles with these 3 categories!
TSS 58 (note 55 minute)
TSS 67 (note 55 minute)
TSS 71 (note 55 minute)
Many riders tend to focus on what happened in today’s ride. It is a tremendous feat to hit your training goals in a single session, however, that is the equivalent of focusing on your diet for one day. A single day of dieting won’t make a difference if the next 6 days are spent gorging yourself into a food coma.
While TSS can be helpful in your long-term training program, there are some things all coaches (and riders) should know:
- Management of exercise volume can increase the efficiency of training while helping you avoid over-training. TSS is primarily used to determine the best combination of workouts and recovery over a mesocycle of 3-4 weeks. Your daily TSS information has limited value unless it is used to determine accumulated stress over a period of time (ie a microcycle within a microcycle)
- A training session with a high TSS does not mean high fitness. Subthreshold efforts lasting longer than an hour can result in a higher TSS than a shorter, more intense ride would.
- Comparing your rides by TSS can be misleading. Effort type and workout structure are not factored into the calculation. Something as simple as a high cadence ride can increase the stress response if you are riding outside of your preferred cadence range. TSS does not factor in all physiological demands that impacts you.
- TSS is only specific to the stress produced in that particular activity. It does not account for other stressors, like your job, sleep quality, biomechanical issues, inefficiency, impending infections, etc.
- The amount of training load that individuals can tolerate will differ. The goal of completing a higher TSS ride should fit within your overall training plan.