Threshold Power: One Method to Determine Training Zones

It’s that time of year when everyone is thinking about the upcoming season, planning events and epic rides throughout the summer. There is no shortage of amazing events available on the MTB, gravel bike or road bike. Whether you’re racing downhill, chasing endures or finding the latest amazing gravel event you will benefit from consistent training. 

One of the first steps in consistent training is to determine your Threshold and then build out some training zones. In the world of training with power, Threshold Power is what you could hold for 1 hour of very hard riding. Not many people like to do a 1 hour test so there are a couple of ways to figure out your Threshold. 

One method is to follow a protocol to determine your Functional Threshold Power (FTP). This is done by doing a 20 minute test using a power measuring device, whether it be an onboard power meter on your bike or a trainer that measures power. Your effort should be as hard as you can maintain steady for an hour. The effort should be constantly reassessed. Think about if you could go just a little stronger or if you need to stay right where you’re at in order to hang on to the consistency of the effort. 

Here’s an example of power test data on an indoor trainer of a client who was starting up their program in November. They had a solid base through the summer and then took a bit of time off in the early fall. You can see with their heart rate (red line) that they put in a very consistent effort with no big spikes, rather just a smooth and steady effort. 

The time off during the early fall depleted their long range so you’ll notice at about 15 or 16 minutes into the effort there starts to be more variability in power (pink line). The client’s overall endurance capability had faded a bit, however it wasn’t super dramatic. The best part of showing consistency in this test is looking at the rider’s cadence (yellow line), ranging between 88-99RPM and averaging at 95RPM. 

That steadiness is hard to accomplish out on the road or trail. It’s definitely better to have a steady and consistent test to determine a proper FTP. 

Our rider averaged 280 Watts for the 20 minute test. He fought with the power over the final few minutes a little bit, however the variability wasn’t so great that I would consider it to be too inconsistent. The established literature on power testing suggests taking 95% of the average from the test to determine FTP, so this rider’s working FTP would be 266. From there you build out your training zones: 

  • • Active Recovery - <55% 

  • • Endurance - 55-75% 

  • • Tempo - 76-90% 

  • • Threshold - 91-104% 

  • • VO2Max - 105-120% 

  • • Anaerobic - >120% 

  • • Nueromuscular – All Out!!! 

Awesome! Now you have some zones to base your training. Finding or developing a progressive training plan is the next step. At MTN RDY we have you covered!