Measuring Your Progress
At Purplepatch, we use a variety of steady-state intervals and field tests to determine training zones and measure fitness.
WITH POWER: A simple field test can determine functional threshold power (FTP)—your best one-hour average power. We have athletes do a 5-minute best effort time trial, rest 7–10 minutes, then do a 20-minute steady-state best effort. Average power and heart rate can provide an estimate of functional threshold and training zones (see below). Most triathletes will spend the majority of their training time in Zones 2 and 3, with some specific doses of Zone 4 or maximal steady-state work.
WITHOUT POWER: If you aren’t able to measure power then you can still complete a 20-minute field test, while measuring your average heart rate through the assessment.
To apply your test results to training zones, follow these estimations based on formulas from Hunter Allen and Dr. Andrew Coggan’s book, Training and Racing With a Power Meter. For FTP, take 95 percent of your 20 minute best effort. So if your best 20 min effort = 210 watts, then your FTP is 200 watts (210 x .95).