Consistency of perceptual and metabolic responses to a laboratory-based simulated 4,000-m cycling time trial.

Although pacing-related research is widely reported, no studies have described the consistency of pacing strategies or their associated energetic contributions. This study aimed to investigate the consistency of pacing and energetic outlay by establishing the typical within and between trial variations during simulated 4,000 m time trials. Fifteen well-trained male cyclists performed three, 4,000 m time trials with 3-7 days separating each trial. Power output, cadence, heart rate, respiratory exchange and iEMG of the vastus lateralis were recorded continuously throughout each trial. To examine within-trial variability, the data were assigned to 10% bins. Rating of perceived exertion and affective response were recorded every 400 m and a capillary blood sample was collected and assayed for blood lactate concentration every 800 m. Mean typical error across trials 1-3 for all variables was low (range 2.1-6.3%) and lower between trials 2-3 for all variables with the exception of cadence. There were no between-trial differences in pacing strategy; however, typical error for each 10% bin was lower between trials 2-3 than trials 1-2. Anaerobic contribution to power was greatest during the first and last 10% of each trial (p > 0.05). In conclusion, well-trained cyclists demonstrated a high degree of consistency in terms of the pacing strategy they adopted which coincided with similar levels of energy distribution and perceived exertion. A laboratory simulated 4-km cycling trial is a reliable test that may be used to monitor performance and pacing strategy.