As stage circuits are not
intended to have a strong cardiovascular (or
aerobic) element, the rest before each subset
of any given exercise is dependant on how long
the last subset took. The rest will be a multiple
of the time the exercise took (e.g. 3:1 or 3 times
the length of time the exercise subset took).

This ratio is always in relation to the previous
set and counts even when moving between exercises.
Therefore, if it took 15 seconds to complete one
of the subsets, then the recovery after it would
be 45 seconds for our example.

Alternatively, the rest could be prescribed as an amount of time, eg 2 minutes.