We have some force workouts today. This can be done on the trainer or outside.
If you are riding outside, find some hills or a flat road with a stiff headwind that will last 1-2 min each, or if indoors, use your trainer resistance stiff. Cadence should be 50-60 RPM for the duration of the interval. Rest 1-2 min between intervals and repeat 10 times. Recover with easy spinning for 10 min. That is 1 set. Repeat 1 or two more times. Heart rate will probably be in zone 3, and may jump into zone 4. If your HR goes into zone 5, increase the cadence.
If you have more time, continue riding at zone 2-3 for the duration of your allowed time.
Force workouts will help build climbing muscles and speed using big gears.