Your Threshold is the intensity level at which your body transitions from aerobic to anaerobic energy production.
Aerobic energy systems are used to produce energy for low-to-moderate exercise. They use oxygen and are fueled primarily by fat.
Anaerobic energy systems power moderate-to-intense exercise. They do not use oxygen and are fueled by carbs/sugar.
In Sixcycle you have four thresholds, one for cycling heart rate, one for cycling power, one for running heart rate and one for running pace.
When you create your Sixcycle account, approximate threshold heart rates will be calculated for you using your age and sex, along with a placeholder threshold pace. It is from these thresholds that your first set of running and cycling zones is created. If you have more accurate thresholds from a field test, LT test, or VO2max test, you can enter them in place of the default thresholds and new zones will automatically be created from the new threshold values.
Similarly, at any time you can enter a cycling power threshold and your zones will be updated to include target wattages.
While heart rate and power thresholds are entered directly in BPMs and watts, respectively, a running pace threshold has a slightly different process:
Click into the Running Threshold Box
Select a distance
Enter your best time for that Distance