A Novel Field Test to Determine Critical Speed

The aim of this study was to assess the reliability of a novel field test of critical running speed (CS). Ten trained

male distance runners completed a familiarisation trial plus three separate experimental trials on a standard 400 m

athletics track. Each trial consisted of three distances (1200, 2400 and 3600 metres) that were selected to produce

finishing times in the region of 3, 7 and 12 minutes respectively. Participants were instructed to cover the set distance

in the fastest time possible. Participants rested for 30 minutes between efforts. Data were modelled using the linear

distance-time model, described by the equation: d = (CS x t) + ARC, where: d = distance run (m), t = running time

(s), and ARC = anaerobic running capacity (m). Results demonstrated a coefficient of variation (CV) of 2.0% (95%

confidence limit (95% CL): 1.4–3.8%) for trials 2–1 and 1.3% (95% CL: 0.9–2.4%) for trials 3–2. There was no

significant difference in CS (m·s-1) across trials (P<0.05). The limits of agreement were ±0.27m·s-1 of the measure

for trials 2–1 and ±0.18 m·s-1 for trials 3–2. ARC proved to be less reliable with a group CV of 18.4% (95% CL: 13.5–

39.9%) for trials 2–1 and 9.8% (95% CL: 7.0–19.6%) for trials 3–2. Although the assessment of ARC is less reliable,

CV data are similar to those reported previously during laboratory-based testing.