What is Training Load?
Better Workouts uses TRIMP or TRaining IMPulse to calculate training load or effort.
The app specifically calculates a variation called TRIMP exp or Exponential Heart Rate Scaling.
The metric uses Heart Rate Reserve and an exponential scaling factor to account for the fact that higher intensity training as a disproportionately high training impact. The formula for calculating TRIMP exp is:
TRIMP exp = sum(D x HRr x 0.64ey)
- D is the duration in minutes at a particular Heart Rate
- HRr is the Heart Rate as a fraction of Heart Rate Reserve
- y is the HRr multiplied by 1.92 for men and 1.67 for women.
A worked example would be a male athlete with a HRmax = 200 and HRrest = 40 training for 30 min. at 130 BPM. The TRIMP exp is therefore:
TRIMP exp = 30 x (130-40) / (200-40) x 0.64e ^(1.92 x (130-40) / (200-40))
Which simplifies to:
TRIMP exp = 30 x 0.56 x 0.64e ^(1.92 x 0.56)
Which is a value of 32. This is obviously a simplified example as in reality an athlete heart rate will vary over time.