Try this one-hour ride from One-Hour Workouts!
Flux efforts are high-intensity, 8-second sprint efforts followed by a recovery period. They are best performed seated on an indoor trainer, starting at 85 to 90 rpm. At the end of the 8 seconds your cadence should be between 125 and 145 rpm. If your cadence is below this, use an easier gear; if your cadence is above this, use a higher gear. The recovery period should be performed in the same gear. Toward the end of the recovery period you will need to increase your cadence to 85 to 90 rpm to get ready to start the next effort.
These flux sprint sessions offer one of the highest-intensity workouts performed on the bike and are ideal for developing power, acceleration, and speed. The level of fatigue can be very high, as the sessions will tax most of your muscle fibers.
Your heart rate will continuously rise after your 8-second sprint, so if you’re using a heart rate monitor you’ll see some interesting graphs. You may find it takes considerable time for your heart rate to drop after the entire session because of the high fatigue.
10 min.: Easy riding RPE 1
2 x 30 sec.: Build effort RPE 2 (90-sec. recovery between reps)
4 min.: Moderate effort at 100 rpm RPE3
2 x 10 min.: 8-sec. maximum efforts RPE 5 (5-min. recovery between reps)
5-10 min.: Easy riding RPE 1
This workout is from One-Hour Workouts, a collection of 50 swim, bike, and run workouts from top triathlon coaches that anyone can fit into a lunch hour–including warm-up and cool-down. Each of the 50 workouts in One-Hour Workouts are tightly focused on one goal so that athletes can get a quality training session in just one hour. Athletes can choose from base, tempo, or speed workouts in each sport to match their training plan’s goal for the day.