Borg scale

The Borg scale is a form of rating scale.

It can be compared to other linear scales such as the Likert scale or a visual analogue scale. The sensitivity and reproducibility of the results are broadly very similar, although the Borg may outperform the Likert scale in some cases.

Use in sports psychology
In sports psychology and particularly exercise testing, the Borg RPE Scale measures perceived exertion. In medicine this is used to document the patient's exertion during a test, and sports coaches use the scale to assess the intensity of training and competition. The original scale introduced by Gunnar Borg rated exertion on a scale of 6-20. Borg then constructed a category (C) ratio (R) scale, the Borg CR10 Scale. This is especially used in clinical diagnostic of breathlessness and dyspnea, chest pain, angina and musculo-skeletal pain.

The seemingly odd range of 6-20 is to follow the general heart rate of a healthy adult by multiplying by 10. For instance, a perceived exertion of 12 would be expected to coincide with a heart rate of roughly 120 beats per minute.