fitness and wellness
Working hard!

fitness magazine in bangalore

Effective strength training is not only defined by heavy loads, subjective perception is a crucial factor. Various scales of exertion are used to measure effectiveness.

Effective strength training should be devised based on the use of individual resources or current individual performance; not just on the load to be moved. This applies to both endurance training and strength training.
The objective exertion parameters in endurance training are widely known; for example heart rate or lactate value. Together with the objective load parameters of running speed (load level) and running time (load time) it is possible to devise reliable, practical and effective training.

In contrast to this, strength training is, in most cases, devised solely on load level. This relative load is usually specified as a percentage, for example the one repetition maximum (1RM):

  • 60-85% to increase muscle mass or
  • 50-60% to improve muscular endurance.

Confusion soon results with these variable percentages because, on the one hand these load specifications lead to very different load times or repetition times depending on the fitness level and training exercise.

On the other hand, estimating the training weight with reference to the 1RM does not lead to reliable information for different training methods aimed at hypertrophy or improving muscular endurance.

Solving the problem

The obvious difficulties in devising training are not surprising as the focus is merely on load parameters. Instead of this, the exertion of the person training should be taken into account. The exertion or stress ratio of the individual resources is the parameter that leads to the desired effects of strength training.

As adequate objective exertion parameters do not exist for every day strength training, the subjective individually perceived exertion must become the training control parameter.

The individual exertion can either be determined

  • from the relation between the number of repetitions completed and the number of possible repetitions or
  • Indirectly using the global subjective assessment of exertion or effort.

While the relation between the number of repetitions completed and the number of possible repetitions allows for an assessment specific to the task or training exercise, the information about perceived exertion tends to be used as a general assessment of exertion during training.

The perceived exertion corresponds to the often misunderstood and incorrectly used term of training intensity in strength training. Although generally perceived exertion is influenced by psychological factors – for example training experience – as well as situational factors, the perceived exertion at least shows a close relationship between physiological parameters such as heart rate, oxygen intake and blood lactate concentration with endurance training.

The perceived exertion is, therefore, also referred to as a psycho-physiological integrator, which can validly be used to control and regulate training intensity. But how do you measure training intensity or perceived exertion?

Different scales

6   No exertion at all
8   Extremely light
9   Very light
11  Light
13  Somewhat hard
15  Hard
17  Very hard
19  Extremely hard
20  Maximal exertion

Fig. 1: Borg scale (rating of perceived
exertion scale, RPE)
Training is often only assessed as being effective if you have worked up a sweat. The effectiveness of strength training could be assessed accordingly easily using the question ‘Did you work hard enough?’ and the answer is ‘Yes!’ or ‘No!’

Regardless of the type of training (strength or endurance), personal or group fitness, this one-word answer is, of course, inadequate for devising effective training in the fitness and health industry.

Some experts have, in fact, stated that full capacity and therefore maximal exertion must be the aim for effective strength training. But in popular sports, health related fitness and sports for senior citizens, among children and youngsters’ training – and in prevention and rehabilitation in particular – no maximum adjustment processes are aimed. Instead, it is an optimum: average to sub-maximal adjustment processes.

Probably the most well-known exertion scales come from Gunnar Borg, who has already dealt with perceived exertion intensively in the 1960s and 70s. The most widely used scale in sports science and sports medicine tests, also generally referred to as the Borg Scale (rating of perceived exertion or RPE), is based on the heart rate (60 to 200 heart beats/minute) with levels 6-20 (Fig.1).


0   Very, very light
2   Very light
4   Light
6   Hard
8   Very hard
10  Very, very hard

Fig. 2: Exertion scale for strength training
with children and young people.

For strength training Borg recommends that the person training should start with eight to ten repetitions with a perceived exertion of “somewhat hard” (12-13) and should end each series with “hard” to “very hard” (levels 15-17). In doing so it is presumed that the chosen load can still be moved during the last repetition.

With patients in rehabilitation, Borg recommends starting with a perceived exertion of levels 9-11 and ending with 13-14, although the concrete specifications should be decided in consultation with a doctor. The perceived exertion increases from the minimal to individual maximal capacity linearly and is a reliable and valid measurement method.

However, it is difficult to assess exertion if a scale starts with 6 and ends with 20. Borg, therefore, transformed the scale and adapted the perceived exertion to a scale of 0-10. Despite this, the subjective perception of exertion is still difficult, if not all levels are labelled (Fig.2) with an exertion attribute like “light” or “very hard” and the number of levels between the given attributes differ.

Objective scale

There are a number of other scales for training children and young people, which have been similarly criticised or have not been empirically tested. As far as the aim of basing strength training on exertion (not load) is concerned, there is still therefore a need for a reliable, valid, economical and above all practical exertion scale, not just for fitness and health related training.

So much exertion, I have to stop (10)
Maximal exertion (9)
Extremely hard (8)
Very hard (7)
Hard (6)
Moderately hard (5)
Quite light (4)
Very light (3)
Extremely light (2)
No exertion at all (1)

Fig. 3: The sports exertion scale from the Institute
for Advanced Training Science in Leipzig (Germany).
Another scale, the sports exertion scale (Fig.3), was developed at the Institute for Advanced Training Science in Leipzig, taking the aforementioned criticisms for competitive sports training into account. It includes exertion attributes for levels 0-10 and has been evaluated by young and adult athletes.

The ASS provides objective, reliable data and can be used in a table or graph form. Tests conducted so far show that the scale is used consistently by both young people and adults and is referred to as being practical and economical. But the scale still has to be tested in more training and age ranges.

– IFHIAS Institute



The authors of the study are Dirk Büsch, Franz Marschall, Kai Schumacher, Jan Pabst, Falk Naundorf, Jelena Braun, Andreas Wilhelm & Urs Granacher (



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