The latest release of iSMARTtrain includes analysis of training sessions using TRIMP. This document gives an overview of what TRIMP is, and how it is implemented in iSMARTtrain.

What is TRIMP?

TRIMP is a method of quantifying a training session or race. The basic method was developed by Dr. Eric Bannister in the mid-70’s. It is calculated as the product of the Training Volume and the Training Intensity. In it’s simplest form, it’s the duration of the session x average heart rate:

45 minutes at an average HR of 150 = 45 * 150 = 6750

A limitation of this method of calculation is that it does not differentiate between the intensity levels of training. For example, the TRIMP value for 45 minutes at a heart rate of 150 is the same as 37 minutes at 180 bpm, but these are very different training levels.

To overcome this the HR zone was used to add a ‘weight’ to the calculation. For example:

15 minutes in HR Zone 1, followed by 15 minutes in HR Zone 3 gives:

(15 x 1) + (15 * 3), give a TRIMP score of 60

Co-developer and Sports Scientist Joe Beer ( has reviewed recent research in the area [1,2,3,4] and from this we set the three zone method based the average from known elite data.

The five zone method can be set as follows [5]:

Zone 1 50 to 60% HRmax

Zone 2 60-70

Zone 3 70-80

Zone 4 80-90

Zone 5 90-100

How is TRIMP incorporated in to iSMARTtrain?

TRIMP has been incorporated in the latest release of iSMARTtrain. As each session is downloaded from the HRM, the TRIMP value is calculated and displayed in the Summary Panel. The total TRIMP value for the week is shown in the summary column in ‘Month View’

The Zones used for the calculation are set in the Preferences dialog. Initially, each zone has a weight of 1, 2, 3, 4, or 5. The weight can be changed, using the ‘Advanced’ button in the ‘HR Zones’ tab of the Preferences dialog.

Using the ‘Summary Graph’, and selecting ‘TRIMPS’ in the ‘Show Me’ popup menu, it’s possible to see the total TRIMP score for each week or month. This will show how the load of your training has varied over time.


[1] Galy et al(2003)

[2] Lucia et al (2003)

[3] Siler & Kjerland (2004)

[4] Esteve-Lanao et al (2005)

[5] Foster et al (2001)