Training impulse

Training impulse or Trimp (sometimes TSS) is a measurement of the impulse each training has on your body. This impulse causes adaptions within your body to become fitter. A few examples of such changes are:

  • muscle growth
  • improved fat metabolism
  • increased number of mitochondria
  • improved neuromuscular coordination
  • improved efficiency
  • higher oxygen consumtion (VO2max)
  • and much more

It is difficult to measure this impulse with classic training data like time, distance and speed. A 10k run over one hour will cause only a few adaption processes for an experienced marathon runner compared to a novice. With the training impulse you can now compare these differences.

The maximum training impulse that can be accumulated over one hour are 100 points. On your bike this corresponds with your FTP. This is the maximum power you can sustain for one hour.

For swimming and running we use the critical velocity as a speed that can be sustained for one hour. PerfectPace can calculate the critical velocity from your 100m and 400m PB (swimming) and 10k PB (running).

One hour of swimming or running at your critical velocity results in a training impulse of 100.

Training activities that are shorter than one hour are a special case. Because the training duration is shorter than one hour you are able perform at a higher intensity than over the duration of one hour. For a 30 minute all-out session the training impulse will be higher than 50 and might be around 55.
This is also the reason why you can’t reach 200 points in two hours as the 100 points for one hour result from the all-out performance that you can hold for one hour and not longer.

However training in this extreme zone should be the exception anyway. Most of the training is going happen in the endurance zone where 50-60 points per hour will be achieved.

The table below might be helpful to estimate the training impulse in advance.

Training zone 30min Trimp 60min Trimp 120min Trimp
Active recovery
10-25
20-50
40-100
Endurance
25-30
50-60
100-120
Tempo
30-40
60-80
120-160
Threshold
40-50
80-100
160-190
VO2max
50-55
100
190

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