It assesses your swimming at any effort level, whether you are swimming easy, sprinting, or anywhere in-between.
If you are in the red zone then you will be aware that you are "over-revving" and need to slow things down slightly and lengthen out your stroke. You can use a Tempo Trainer Pro to do that in mode 3. First set it to your current stroke rate, and then progressively lower it (2 to 3 SPM at a time) until things are feeling more controlled.
BUT if you are in the blue zone you need to be a little careful. Ultimately with yourself we are looking to raise your stroke rate slightly, getting a better sense of rhythm and timing into your stroke. However, you can't just speed your arms up - if you've tried that you know it gets very hard very quickly!
The reason for this relates to why your stroke rate is too low. If you are in the blue zone then it's very likely you are "overgliding" at the front of the stroke, dropping your wrist and elbow and showing the palm of the hand slightly forwards.
Here's how that looks:
If you've been focusing on developing a long stroke (or actively trying to glide) then showing the palm forwards naturally starts to develop in your stroke. That's because pushing forwards like this allows you to pause momentarily in this position, in fact it's very hard to pause out front without doing so!
We often refer to this effect as "putting on the brakes" and it quickly becomes a habit such that you are unaware you are doing it. If you try and lift your stroke rate from here you simply push forwards on the water harder and it resists you more, hugely increasing drag and effort.
Instead, we need to first develop your catch setup so that you extend forwards into this position with the elbow higher than the wrist and the wrist higher than the fingertips:
Now you are naturally engaging with the water and ready to press it backwards, removing that pause at the front. Do this and you will find your stroke rate will naturally lift, possibly without you even realising it.
Correct Your Stroke With Swim Smooth
If you are in the red zone, with a Guru Pro subscription follow either the Arnie or Swinger processes and tune up these elements of your stroke. You'll move into the white zone and immediately notice the difference in your swimming:
To fix an overglide at the front of your stroke (Blue Zone) then follow the Bambino or Overglider Pro Guru processes and you'll soon be swimming much more effectively: