Recently I attended a course aimed at beginner coaches. Part of the course included a discussion of fundamental training factors. During this section the coaches in attendance were asked to define intensity and volume. The answer that came back was “…volume is how much and intensity is how hard.” Following up on this question the facilitator then asked for “ways that the intensity could be increased.” One of the answers that came back was “reducing the rest between repetitions.” To my surprise no one challenged this!

Mount Everest North Face

Which is more intense: walking at sea level or walking at the top of Mount Everest? Now which is more effort?

Reducing rest periods does not increase intensity. Anyone who has ever trained as an athlete knows that if they rest less time between sets they can’t run as fast, throw or jump as far or lift as much weight as they could if more rest was taken. So how could anyone make this mistake and more importantly how could twenty coaches in a room fail to see the error in this logic?

In retrospect I don’t know why I was so shocked. As a throw away comment it sounds perfectly acceptable to the untrained ear. But it reminded me of a fundamental misunderstanding that is pervasive among novice coaches – the failure to differentiate between effort and intensity. The reason the group did not challenge the statement that reducing rest increases intensity is because they accepted the idea that intensity relates to how hard the athlete is working.

The word ‘intensity’ is one of the most misused terms in training because it is often confused with ‘perceived effort’. Novice coaches especially often confuse how “hard” an exercise is with intensity primarily for two reasons:

  1. In weight training the intensity of the exercise is often equated with the amount of weight lifted. The heavier a weight the more you “feel it” and so the “harder” it is to lift.
  2. In endurance training as the pace of running increases the pathways primarily being used to fuel the exercise switch from aerobic to anaerobic. When the body is operating predominantly aerobically you do sweat and it is hard work but it’s nowhere near as painful as the lactate burn that builds up as running speed increases.

However, just because the discomfort increase does not necessarily mean the intensity has also increased. To challenge peoples’ assumptions about the relationship between intensity and hard work I often ask the following question:

Which is harder work? Running a five-minute mile at sea level or walking 100m at the top of Mount Everest?

Now anyone who has ever run a five-minute mile will attest that it is “very hard work” but if you then whisked that same person up to the top of Everest and challenged them to walk 100m they would probably fail to make it even 20m before collapsing with exhaustion. Does that make walking 100m at the top of Everest a higher intensity exercise than running a five minute mile at sea level? Of course it doesn’t! While intensity and hard work do often progress together they are in fact two separate entities and so do not necessarily have to.

Intensity defined

“Intensity relates to the power output generated by the athlete during exercise.”

Intensity relates to the power output generated by the athlete during exercise. In practical terms if you run faster, jump higher or throw further your power output increases. Power output can also be objectively measured using a stop watch, a tape measure or special scientific equipment (such as a force plate or radar gun).

“Effort is the subjective experience of the individual undertaking training.”

On the other hand, “hard work” or “perceived effort” refers to an individual’s perception of the how hard they are working or the level of discomfort during or immediately after exercise, which can only be subjectively measured.

Why is it important to understand the difference between intensity and effort

In Athletics it is essential that a coach understands the difference between intensity and effort. Otherwise, they are are likely to misjudge the impact certain types of training have on the human body. As a general rule of thumb the higher the intensity (power output) of an exercise the greater the impact it has on the human nervous system. This means the body needs more time to recover before it can repeat high intensity activity. If this recovery window is not respected then the chances of injury rise dramatically.

As a real life example, let say the athlete runs a great time in a 100m race. They leave the track feel great and hardly at all tired. An uninformed coach may assume this means that they can return to full training the very next day with no rest. After all the run felt so easy. The reality is that the athlete just produced the highest intensity performance of their life. Having run faster than ever before their nervous system has been crushed and it may take days or even weeks to recover. As a result the athlete is slightly less coordinated than usual during training the following day and pulls their hamstring. They are now out of action for at least 8 weeks.


When coaching Athletics it is important to recognise the difference between intensity and (perceived) effort. Intensity is an objective, measurable parameter that relates to the power output of the activity. If you run faster, jump higher or throw further you are operating at a higher intensity than you have previously. Effort is a subjective experience of the individual. What one person finds hard someone else might find easy.

It is also important to recognise that intensity can stay the same while effort increases. For example, walking 100m at sea level vs 100m at the top of Everest are equally intense activities but the subjective experience is completely different. At sea level, a 100m walk may be a relaxing experience but repeat the same feat at to the top of a mountain and suddenly the effort becomes extreme due to the reduced amount of oxygen available to the athlete.

So next time you hear someone talking about intensity STOP and ask yourself, “how are they defining it?” Do they understand the difference between intensity and effort and if not is it causing them to make mistakes that could otherwise be avoided?


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