20-Minute Bike Time Trial Test: Estimate Your FTP

Session Overview

The 20-minute time trial test is the gold standard for estimating FTP (Functional Threshold Power) without expensive lab testing. This intermediate session helps you establish or re-check your training zones as the race season begins, so your intensity-based training is accurate.

What You’ll Need

  • Turbo trainer or a flat, uninterrupted road (5km+ preferred)
  • Power meter (recommended) or heart rate monitor
  • Cycling computer or GPS watch
  • Water bottle
  • Good warm-up — do not skip this

Warm-Up (15 minutes)

This warm-up is non-negotiable for a time trial effort. Spend 10 minutes building from easy to moderate effort, then include 2 x 1-minute hard efforts at around 95% max effort with 2 minutes easy between each. Finish with 3 minutes easy before starting the test. Your muscles and cardiovascular system must be fully primed.

Main Set

The test itself is 20 minutes of maximal sustainable effort — the hardest pace you can hold for exactly 20 minutes without slowing in the final few minutes. Aim for even pacing. Going out too hard and dying at the end invalidates the result.

  • Minutes 1-5: establish effort — slightly conservative, resist the urge to go all-out immediately
  • Minutes 5-15: find your maximal sustainable pace, focus on breathing rhythm
  • Minutes 15-20: if you have anything left, give it in the final 2 minutes
  • Record: average power (watts), average heart rate, average speed

Cool-Down (10 minutes)

Spin easily at 80-90rpm for 10 minutes. Do not stop abruptly — blood pooling in the legs causes lightheadedness after hard efforts. Hydrate immediately and take on carbohydrates within 30 minutes of finishing.

Coaching Notes

  • Your FTP estimate = average power for the 20 minutes x 0.95
  • A poor warm-up will produce a result 5-10% lower than your true FTP — never skip it
  • Repeat this test every 6-8 weeks to track fitness progress and recalibrate training zones
  • For heart rate users: FTP heart rate is roughly your average HR for the 20 minutes x 0.95

Training at your own risk. The information provided is for general guidance only and is not a substitute for professional medical advice. Please consult a doctor before starting any new exercise programme, especially if you have any pre-existing health conditions.