Some ideas how to train with running power
The following workouts exemplarily show how power-based training can look in reality. For more workouts and to learn how to incorporate them into a goal-oriented training plan, have a look at "Power to Trail and Ultra Runners".
3 x 20 min
This is a demanding training that requires a well-developed base endurance. It is especially suited for training uphill running or speed hiking. In that case, you can use the recovery sections for going down again (at least partly).
Here's an example of what the power output and altitude profile can look like. The power was calculated with RunPowerModel. The forest path had an incline of roughly 15%.
This is a very good example of how training with power helps to properly set the training intensity, avoiding overshooting at the beginning and still being able to keep the proper level towards the end.
The following figure illustrates another 3 x 20 min session, here carried out under variable conditions.
The first high-intensity section began on a flat road, followed by an uphill part. The second one happened on hilly terrain, consisting of many short uphill and downhill parts. The power profile is now more jagged because it is harder to keep a consistent power output under these conditions (which is a good thing, enforcing a high power level during a downhill part should generally be avoided because of high injury risk). If you're feeling good that day, such as I did, you can try to push a bit more for the last block.
8 x 3 min on different terrain
These shorter intervals are great for boosting your VO2max performance. Depending on your running performance, these are close to 1 km intervals. Using a running power meter has the advantage that these can quite easily be carried out on terrain with different slopes, as shown in the following plot:
In the shown example, the first five high-intensity blocks were run on a flat road, followed by the last three ones on an uphill forest road. Combining intervals on different terrain into a single training session is a great way of accustoming the body to varying conditions such as those encountered in trail-running races as well as avoiding monotony.
The credit for this workout goes to this webpage, I took the freedom to translate the paces listed therein into power. It's a fun interval workout with different target intensities that are kept for varying durations, followed by equally long rest periods. In case you still feel fresh enough at the end, you can add some short-duration sprints afterward.
Here's the power profile of an example run of the 1-2-3-2-1-2-3-2-1 workout where I carried out most (but not all) high-intensity parts uphill: