Reliability of mean power recorded during indoor and outdoor self-paced 40 km cycling time-trials

M.F. Smith, R.C.R. Davison, J. Balmer, S.R. Bird

Research output: Contribution to journalArticlepeer-review

79 Citations (Scopus)


The purpose of this study was to assess reliability of both indoor and outdoor 40 km time-trial cycling performance. Eight trained cyclists completed three indoor 40 km time-trials on an air-braked ergometer (Kingcycle) and three outdoor 40 km time-trials on a local course. Power output was measured for all trials using the SRM powermeter. Mean performance time across three indoor trials was 54.21 +/- 2.59 (min:sec) and was significantly different (P<0.05) to mean time across three outdoor trials (57.29 +/- 3.22 min:sec). However, there was no significant difference (P = 0.34) for mean power across three indoor trials (303+/-35W) when compared to outdoor performances (312 +/- 23 W). Within-subject variation for mean power output expressed as a coefficient of variation (CV) improved in both indoors and outdoors for trials 2 and 3 (CV = 1.9%, 95% CI 1.0 - 3.4 and CV = 2.1 %, 95 % CI 1.1 - 3.8) when compared to trials 1 and 2 (CV=2.1%, 95% CI 1.2-3.8 and CV=2.4%, 95% CI 1.3-4.3). These findings indicate that power output measured using the SRM powermeter is highly reproducible for both laboratory-based and actual 40 km time-trial cycling performance.

Original languageEnglish
Pages (from-to)270-274
Number of pages5
JournalInternational Journal of Sports Medicine
Issue number4
Publication statusPublished - May 2001
Externally publishedYes


  • cycling performance
  • reproducibility
  • SRM powermeter
  • fixed-distance


Dive into the research topics of 'Reliability of mean power recorded during indoor and outdoor self-paced 40 km cycling time-trials'. Together they form a unique fingerprint.

Cite this