5K and 10K race pace sits near threshold

A 5K is run at about critical speed. A 10K sits close to it; for faster runners it falls in the range a review places above critical speed, while for slower runners whose 10K takes well over 30 minutes it likely falls at or just under it (no study has measured this directly).

Why it works

Critical speed is the fastest pace with a physiological steady state; above it, oxygen uptake and blood lactate keep rising until you have to stop, so efforts above it last minutes, not hours. Shorter races sit at or above it; the half marathon and marathon sit below.

What it means in practice

For 5K and 10K plans, goal-pace work sits at or close to threshold, so race-pace repeats also train the threshold. Say a 5K is run at about threshold, and a 10K close to it; do not say a recreational 10K is raced above threshold. Never give a percentage of critical speed for a 10K. In 5K reviews, gloss threshold as the fastest pace you can hold steadily, not as one-hour race effort, and do not cite a hold time for critical speed.

The evidence

• Jones, A.M., Vanhatalo, A. (2017). The 'Critical Power' Concept: Applications to Sports Performance with a Focus on Intermittent High-Intensity Exercise. Sports Medicine.

  Critical power (critical speed in running) sits above the lactate threshold and is more akin to the maximal lactate steady state; above it, in the severe-intensity domain, oxygen uptake and blood lactate do not reach a steady state. The authors note that the severe-intensity domain encompasses a large swathe of athletic events, in track and field from 800 m up to perhaps 10,000 m. In their analysis of elite marathoners, the marathon was completed at 96 ± 2% of critical speed.

• Figueiredo, D.H., Figueiredo, D.H., Manoel, F.A. et al. (2021). Peak Running Velocity or Critical Speed Under Field Conditions: Which Best Predicts 5-km Running Performance in Recreational Runners?. Frontiers in Physiology.

  In 25 recreational men, mean 5-km speed (12.0 ± 1.3 km/h) did not differ from critical speed from three track trials (12.1 ± 1.4 km/h), and the authors suggest the 5 km may have been run at intensities close to 100% of critical speed. Citing earlier studies, they note that time to exhaustion at critical speed in running is under 30 minutes, similar to the 25.3 ± 3.0 min 5-km times.

  n=25

Why we call confidence medium

Jones and Vanhatalo (2017, Sports Medicine review) place track events from 800 m up to perhaps 10,000 m in the severe-intensity domain, above critical power. Figueiredo et al. (2021, 25 recreational men) found mean 5-km time-trial speed (12.0 km/h) did not differ from critical speed (12.1 km/h). Medium, not high: the review gives the range as an example rather than a measurement, the field study is small and men only, and no study measures recreational 10K pace as a share of critical speed.

Where it applies

Recreational to trained runners racing 5K and 10K. The 5K figure comes from recreational men with 21 to 33 minute 5K times; the 10K placement comes from the review's track-and-field framing (trained athletes) plus indirect field data.

Does not apply to: the half marathon and marathon, which are raced below critical speed for every goal in the catalog (see recreational-marathon-pace-below-lt); the first (lower) lactate threshold: this claim refers only to the upper threshold (critical speed / maximal lactate steady state); exact percentages of critical speed for recreational 10K runners, which no study has measured.

Plans that respect this

Plans that scored well on the rubric measures informed by this claim.

• 10-Week Advanced 10k Training (5 days)
• 10-Week Run a Faster 10k (3 days)
• 10-Week Run a Faster 10k (4 days)
• 10-Week Run a Faster 10k (5 days)
• 10-Week Run a Faster 10k (6 days)
• 10-Week Run a Faster Half Marathon (3 days)
• 10-Week Run a Faster Half Marathon (4 days)
• 10-Week Run a Faster Half Marathon (5 days)
• 10-Week Run Your First 10k (3 days)
• 10-Week Run Your First Half Marathon (3 days)
• 10-Week Run Your First Half Marathon (4 days)
• 10-Week Sub-1:30 Half Marathon (4 days)