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Running Pace Guide: Splits, Race Predictions & Training Zones

Learn how to calculate and interpret your running pace, plan race splits, predict finish times with the Riegel formula, and train smarter with heart-rate-based pace zones.

March 27, 2026 · 9 min readLast updated: May 21, 2026

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What is running pace?

Running pace is the time it takes you to cover one unit of distance, typically expressed as minutes per kilometre (min/km) or minutes per mile (min/mi). While speed tells you how fast you travel (km/h or mph), pace tells you how long each kilometre or mile takes. Most runners, coaches, and GPS watches default to pace because it maps directly to the experience of racing: you feel every kilometre, and knowing your target split per kilometre lets you adjust effort in real time. Pace is the single most practical metric for planning training sessions, setting race strategies, and tracking long-term improvement.

Pace reference table

Elite

< 3:00/km

World-class and professional athletes competing at international level. Sub-2:05 marathon territory.

Advanced

3:30 - 4:30/km

Experienced club runners with years of structured training. Capable of sub-3:10 marathons.

Intermediate

4:30 - 5:30/km

Regular runners with consistent training. Typical marathon range of 3:10 to 3:50.

Beginner

5:30 - 7:00/km

Newer runners building their aerobic base. Finishing a 5K or 10K is the primary goal.

Recreational

> 7:00/km

Joggers and casual runners prioritising enjoyment, health, or weight management over speed.

Understanding splits

A split is the time recorded for a specific segment of a race or training run, usually each kilometre or mile. Tracking splits reveals whether you are distributing your effort evenly or fading as fatigue accumulates. In races, poor split management is the single most common reason runners miss their target time. A well-executed pacing strategy saves glycogen, delays lactate accumulation, and keeps your heart rate in a sustainable zone for longer.

Common split strategies

Even splits: every kilometre is run at the same pace. This is the most energy-efficient strategy and the easiest to execute with a GPS watch. It works especially well for half marathons and shorter races.
Negative splits: the second half of the race is faster than the first. This requires disciplined restraint in the early kilometres when you feel fresh. It is considered the gold standard for marathon racing because it avoids premature glycogen depletion.
Positive splits: the second half is slower than the first. This happens when a runner starts too fast and cannot maintain the effort. While common among beginners, it is generally undesirable because the time lost in the second half almost always exceeds the time gained in the first.

The negative split advantage

Most marathon world records have been set using negative or even splits. Eliud Kipchoge's 2:01:09 in Berlin (2022) featured a second half roughly 30 seconds faster than the first. Starting conservatively keeps muscle glycogen available for the final kilometres and dramatically reduces the risk of 'hitting the wall' after 30 km.

Race prediction with the Riegel formula

In 1981, researcher Peter Riegel published a remarkably simple equation that predicts race performance across distances: T2 = T1 x (D2 / D1)^1.06. Here T1 is your known finishing time for distance D1, and T2 is the predicted time for your target distance D2. The exponent 1.06 reflects the physiological reality that pace slows as distance increases because the body shifts from aerobic to increasingly glycogen-dependent energy systems. The formula works reliably for distances between 1,500 metres and the marathon, though it tends to be slightly optimistic for untrained runners attempting a large distance jump (e.g., 5K to marathon) without specific endurance preparation.

Example predictions from a 25:00 5K

10K

~52:00

Doubling the distance adds roughly 4% per-km pace slowdown.

Half Marathon

~1:55:00

A realistic target for a well-trained runner with adequate long runs.

Marathon

~4:01:00

Assumes proper marathon-specific preparation including 30+ km long runs.

Training pace zones

Effective training requires running at different intensities on different days. Heart-rate-based training zones translate physiological effort into actionable pace ranges. The five zones below are anchored to percentages of maximum heart rate (max HR), which can be estimated as 220 minus your age or measured with a field test. Each zone targets a different energy system and produces a different adaptation, from building aerobic endurance to increasing VO2max.

Five key training paces

Easy / Recovery (65-75% max HR): conversational pace used for the bulk of weekly mileage. Builds aerobic base, promotes capillary development, and aids recovery between hard sessions.
Tempo (80-85% max HR): comfortably hard effort you could sustain for about 60 minutes. Improves lactate clearance and teaches the body to use fat as fuel at moderate intensities.
Threshold (85-90% max HR): the pace at which lactate begins to accumulate faster than it can be cleared. Sustained intervals of 10-20 minutes at this effort raise your anaerobic threshold.
Interval (90-95% max HR): fast repeats of 400 m to 1,600 m with recovery jogs between them. Targets VO2max and running economy, making you faster at all distances.
Sprint (95-100% max HR): short, all-out efforts of 100-400 m. Develops neuromuscular power, stride efficiency, and top-end speed. Used sparingly to avoid injury.

How to improve your pace

Interval training: alternate fast and slow segments to raise VO2max. Classic sessions include 8 x 400 m at 5K pace with 90-second recovery jogs, or 5 x 1,000 m at threshold pace.
Tempo runs: sustain a comfortably hard pace for 20-40 minutes to push your lactate threshold higher. Over weeks, the pace you can hold at threshold creeps upward.
Hill repeats: run hard uphill for 60-90 seconds, jog back down, and repeat 6-10 times. Hills build leg strength, improve running economy, and reduce injury risk by strengthening tendons.
Strength training: two sessions per week focusing on squats, lunges, deadlifts, and calf raises improve ground-contact mechanics and reduce energy waste. Studies show a 2-5% improvement in running economy after 8-12 weeks.
Adequate recovery: adaptations happen during rest, not during the workout itself. Sleep 7-9 hours, schedule at least one full rest day per week, and space hard sessions 48 hours apart.

The 80/20 rule

Research by Stephen Seiler shows that elite endurance athletes spend roughly 80% of their training volume at easy intensity and only 20% at moderate-to-high intensity. Most recreational runners do the opposite, running too fast too often, which leads to fatigue, stagnation, and injury. Slowing down on easy days allows you to push harder on quality sessions, producing faster long-term improvement.

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