RACLET: the Ramp Above Critical Level Endurance Test to evaluate critical velocity in running.

Critical velocity (Vc) is an important fatigability threshold in running, but only strenuous methods exist to assess it (e.g. time-trials). Based on a novel mathematical model of fatigability, the Ramp Above Critical Level Endurance Test (RACLET), a simple, non-exhaustive, 5-min test to evaluate Vc was developed. This study aimed to test the reliability and validity of the RACLET. Thirty-eight participants performed two RACLET (session 1) and three time-trials (sessions 2-4). For the RACLET, velocity target tracking was guaranteed by either a pacing bike or cones and whistle signals. GPS was used to measure the participants' running velocities. Vc, tau, and DACmax were determined by adjusting the fatigability model on the measured Vmax. The RACLET test-retest and RACLET vs. time-trials parameters were compared for reliability and validity testing, respectively. The RACLET Vc is reliable and valid (mean difference=-1.7+/-1.9% and 6.2+/-6.5%, respectively). Although tau and DACmax presented important variability (s.d. difference = 30%), the combination of the RACLET parameters enabled an excellent prediction of time-trials performance (mean error=- 8.9+/-5.1%, 0.9+/-7.4%, -2.0+/-5.2% for 400, 1500, and 3000 m, respectively). RACLET is a novel non-exhausting test that enables a reliable and valid assessment of the velocity-time relationship parameters.