Comparison of Critical Speed and D′ Derived From 2 or 3 Maximal Tests

Abstract

Purpose: The hyperbolic distance–time relationship can be used to profile running performance and establish critical speed (CS) and D′ (the curvature constant of the speed–time relationship). Typically, to establish these parameters, multiple (3+) performance trials are required, which can be highly fatiguing and limit the usability of such protocols in a single training session. This study aimed to compare CS and D′ calculated from a 2-trial (2-point model) and a 3-trial (3-point model) method. Methods: A total of 14 male distance runners completed 3 fixed-distance (3600, 2400, and 1200 m) time trials on a 400-m outdoor running track, separated by 30-min recoveries. Participants completed the protocol 9 times across a 12-mo period, with approximately 42 d between tests. CS and D′ were calculated using all 3 distances (3-point model) and also using the 3600- and 1200-m distances only (2-point model). Results: Mean (SD) CS for both 3-point and 2-point models was 4.94 (0.32) m·s−1, whereas the values for D′ were 123.3 (57.70) and 127.4 (57.34) m for the 3-point and 2-point models, respectively. Overall bias for both CS and D′ between 3-point and 2-point model was classed as trivial. Conclusion: A 2-point time-trial model can be used to calculate CS and D′ as proficiently as a 3-point model, making it a less fatiguing, inexpensive, and applicable method for coaches, practitioners, and athletes for monitoring running performance in 1 training session.