Test-retest reliability of a 16.1 km time trial in trained cyclists using the CompuTrainer ergometer

Abstract

Laboratory based cycling time trials (TT) are widely used by both researchers and practitioners, as a method of
assessing cycling performance in a controlled environment. Assessments of performance often use TT durations or
distances between 20 min and one hour and in the UK the 10 mile (16.1 km) TT is the most frequently used race
distance for trained cyclists. The 16.1 km TT has received relatively minimal, but increased attention as a
performance criterion in the literature. Therefore, the aim of this study was to assess the reliability of 16.1 km TT
performance in a large cohort of trained cyclists using the CompuTrainer cycle ergometer. Trained male cyclists (n =
58, mean±SD age 35±7 yr, height 179±6 cm, weight 79.1±9.4 kg, VO2max. 56.6±6.6 ml.kg.min-1, PPO 365±37 W)
performed an initial incremental exercise test to determine PPO and VO2max. The participants then performed two
16.1 km TT on a CompuTrainer cycle ergometer separated by 3-7 days. Differences in time, power output and
speed were determined using a Wilcoxon signed ranks or paired t-tests. Reproducibility of the TT performance
measures was performed using the coefficient of variation (CV), intraclass correlations, and typical error (TE). There
were no differences between any of the performance criteria for the whole cohort (Mean difference = 0.06 min, 0.09
km.h-1, 1.5 W, for time, mean speed and power respectively) between TT1 and TT2. All TT performance data were
very reproducible (CV range = 1.1-2.7%) and demonstrated trivial or small TE. The slower cyclists demonstrated
marginally lower reliability (CV range = 1.3-3.2%) compared to the fastest group (CV range = 0.7-2.0%). The 16.1
km TT on the CompuTrainer represents a very reliable performance criterion for trained cyclists. Interpretation of testretest
performance outcomes should be performed in the context of the TE of each performance indicator.