Abstract
This study assessed the reproducibility of performance and selected metabolic variables
during a variable high-intensity endurance cycling test. 8 trained male cyclists (age:
35.9±7.7 years, maximal oxygen uptake: 54.3±3.9 mL·kg − 1·min − 1) completed 4 high-intensity cycling tests, performed in consecutive weeks. The protocol
comprised: 20 min of progressive incremental exercise, where the power output was
increased by 5% maximal workload (Wmax) every 5 min from 70% Wmax to 85% Wmax; ten
90 s bouts at 90% Wmax, separated by 180 s at 55% Wmax; 90% Wmax until volitional
exhaustion. Blood samples were drawn and heart rate was monitored throughout the protocol.
There was no significant order effect between trials for time to exhaustion (mean:
4 113.0±60.8 s) or total distance covered (mean: 4 6126.2±1 968.7 m). Total time to
exhaustion and total distance covered showed very high reliability with a mean coefficient
of variation (CV) of 1.6% (95% Confidence Intervals (CI) 0.0±124.3 s) and CV of 2.2%
(95% CI 0.0 ±1904.9 m), respectively. Variability in plasma glucose concentrations
across the time points was very small (CV 0.46–4.3%, mean 95% CI 0.0±0.33 to 0.0±0.94 mmol·L − 1). Plasma lactate concentrations showed no test order effect. The reliability of performance
and metabolic variables makes this protocol a valid test to evaluate nutritional interventions
in endurance cycling.
Key words
validity - performance - exercise testing - blood glucose - blood lactate - SRM Powermeters
