Bike workout question

Hi all...

Just a quick question about an upcoming bike workout.  Just want to get some clarification about the bold/underlined lines below.  What exactly is that?  I assume the "3-4" is referring to sets?  Thanks for any help you can give me...  -Alan

WU: 10'
MS: These are with your shoes clipped in, and the idea is to focus on one leg at a time.
90” right leg, then 90" left leg.
Next is: 45” right, 45" left, vice versa 2x.
Next: 30” left, 30" right increase cadence each 5’’ to maximum.
Next: 20” right, 20” left for 2’.
15” right, 15 “left for 1’,
10” right, 10” left, for 40”,
5”right, 5” left for 20”.
3–4 x 1’ at max cadence, RI 1’.
3–4 x 15” at max cadence to spinout, RI 45”
CD: 10'