These workouts are excellent for both indoor and outdoor riding. Durations are shortened. Strengthening work included. If you do not know your FTP (Functional Threshold Power) or LT (Lactate Threshold heart rate), contact me and we will help to figure it out (trainandperform@gmail.com). If you have taken a power or heart rate test in the last 18 months, you can use it for these intervals, as they do not require you to be quite as particular as some other types of workouts.