Functional Threshold Power in Cyclists: Validity of the Concept and Physiological Responses

Int J Sports Med. 2018 Oct;39(10):737-742. doi: 10.1055/s-0044-101546. Epub 2018 May 25.

Abstract

Functional threshold power is defined as the highest power output a cyclist can maintain in a quasi-steady state for approximately 60 min (FTP60). In order to improve practicality for regular evaluations, FTP60 could theoretically be determined as 95% of the mean power output in a 20-min time trial (FTP20). This study tested this assumption and the validity of FTP20 and FTP60 against the individual anaerobic threshold (IAT). Twenty-three trained male cyclists performed an incremental test to exhaustion, 20- and 60-min time trials, and a time to exhaustion at FTP20. Power output, heart rate and oxygen uptake representing FTP20, FTP60 and IAT were not different (p>0.05), and large to very large correlations were found (r=0.61 to 0.88). Bland-Altman plots between FTP20, FTP60 and IAT showed small bias (-1 to -5 W), but large limits of agreement ([-40 to 32 W] to [-62 to 60 W]). Time to exhaustion at FTP20 was 50.9±15.7 min. In conclusion, FTP20 and FTP60 should not be used interchangeably on an individual basis and their validity against IAT should be interpreted with caution.

MeSH terms

  • Adult
  • Anaerobic Threshold / physiology*
  • Bicycling / physiology*
  • Exercise Test / methods*
  • Heart Rate
  • Humans
  • Lactic Acid / blood
  • Male
  • Oxygen Consumption
  • Perception / physiology
  • Physical Endurance / physiology*
  • Physical Exertion
  • Reproducibility of Results
  • Time Factors

Substances

  • Lactic Acid