Int J Sports Med 2018; 39(10): 737-742
DOI: 10.1055/s-0044-101546
Training & Testing
© Georg Thieme Verlag KG Stuttgart · New York

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

Fernando Klitzke Borszcz
1  Centro de Ciências da Saúde e do Esporte, Universidade do Estado de Santa Catarina, Florianopolis, Brazil
,
Artur Ferreira Tramontin
1  Centro de Ciências da Saúde e do Esporte, Universidade do Estado de Santa Catarina, Florianopolis, Brazil
,
Arthur Henrique Bossi
2  School of Sport & Exercise Sciences, University of Kent, Chatham, United Kingdom of Great Britain and Northern Ireland
,
Lorival José Carminatti
1  Centro de Ciências da Saúde e do Esporte, Universidade do Estado de Santa Catarina, Florianopolis, Brazil
,
Vitor Pereira Costa
1  Centro de Ciências da Saúde e do Esporte, Universidade do Estado de Santa Catarina, Florianopolis, Brazil
› Author Affiliations
Further Information

Publication History



accepted 15 January 2018

Publication Date:
25 May 2018 (online)

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.