So for cycling EF is basically power divided by heart rate; or in an oversimplified way, how many watts you get per heart beat.
The more watts you get per heart beat the better. You can track this over time as a proxy of your aerobic fitness.
If month after month, your EF factor increases, that suggests your fitness is also improving. Like an FTP test you'd need to do this test under repeatable conditions to be worthwhile.
You can also compare EF within a workout. If you've ever ridden in erg mode for an extended period of time, you'll probably have noticed that your heart rate steadily increases. There are a variety of reasons why your heart rate may increase (e.g. body temp rises, ambient temp rises, dehydration, lose mental focus and technique becomes sloppy, etc). Let's say you do a 3 hour erg workout on constant power, you can figure out EF for the first and second half. If your EF drops a lot in the second half you know there is a potential area of your game to work on.
Like FTP, you can use these measures to understand when your training plan is failing to provide performance improvements, although knowing what amendments to take requires some judgement.
The more watts you get per heart beat the better. You can track this over time as a proxy of your aerobic fitness.
If month after month, your EF factor increases, that suggests your fitness is also improving. Like an FTP test you'd need to do this test under repeatable conditions to be worthwhile.
You can also compare EF within a workout. If you've ever ridden in erg mode for an extended period of time, you'll probably have noticed that your heart rate steadily increases. There are a variety of reasons why your heart rate may increase (e.g. body temp rises, ambient temp rises, dehydration, lose mental focus and technique becomes sloppy, etc). Let's say you do a 3 hour erg workout on constant power, you can figure out EF for the first and second half. If your EF drops a lot in the second half you know there is a potential area of your game to work on.
Like FTP, you can use these measures to understand when your training plan is failing to provide performance improvements, although knowing what amendments to take requires some judgement.