This

Proper warm up - 20 minutes or so (do this properly - including some intense efforts for a few seconds)

Then - and this is the unpleasant bit - you have to ride as hard as you can sustain for 30 minutes.

After 10 minutes of that, start your heart monitor, and record your average heart rate for the next 20 minutes.

Try to keep the same cadence over the 20 mins - about 90-100 rpm, if you have a monitor.

By the end you should feel like you just want to fall off the bike and curl up.

Your average heart rate over that 20 mins is your threshold heart rate.

It's a bit unpleasant. But v useful for pretty much any training plan.

Posted By: Tricky Hawes, Sep 19, 22:11:46