Perceived effort is a scale of 1 to 10 used to determine how much effort you personally are putting into a run. This means you’re not running to meet a specific time goal such as a 8 minute mile or completing 10 miles in 90 minutes. Perceived effort means how much effort you feel you are putting into a particular run. What each point on the scale means is different for every person and for each run.
If you have a hard workout, your perceived effort will reflect that in the next days run because a pace that is easy for you will be more challenging to maintain. This is normal and in fact if it’s now happening you are either exceptional at recovery or you are not pushing yourself hard enough in your hard workouts.
Why do we use perceived effort to measure how difficult a run is or how hard we should be pushing on a particular day? it is more personal and therefore more effective for you as an individual runner. If you are working with a training program you pulled off the internet, it doesn’t account for you as an individual. It is made to work for a range of people. Perceived effort let’s you adjust on the move and from day to day.
If a workout is supposed to be hard, you know what hard feels like on that day and you can push yourself to that level. Hard workouts should be competed at a 7 or 8 on the perceived effort scale. There are few times you want to push all the way to 9 or 10, maybe the last quarter mile of a run or a race. Easy runs should be completed at a 3 or 4. Tempo runs should be done at a 5 or 6, hard but maintainable for 6 to 8 miles.
Running based on perceived effort helps you ensure that your training is going to have the intended impact. If you are always running at a high level, you don’t let your body recover. No recovery means no progress.
Is running by time rather than perceived effort useful? yes, in small doses. It is a good way to see how you are progressing in your training. Mostly running by time should reserved for races.