What is a Positive Split?

A Positive Split occurs when you run the second half of a race slower than the first half. Despite the "positive" name, it's generally considered a pacing mistake.

Example

Marathon total time: 4:00:00

• First half: 1:52:00
• Second half: 2:08:00

Positive split: +16 minutes 😰

Why It Happens

1. Starting Too Fast

Adrenaline and crowds push you to unsustainable speeds early on.

2. Poor Fueling

Running out of glycogen (hitting the wall) causes dramatic slowdowns.

3. Underestimating the Distance

Feeling great at mile 10 doesn't mean you'll feel great at mile 22.

4. Heat & Humidity

Weather conditions that worsen during the race.

The Statistics

Research shows that most amateur runners run positive splits:

• 90%+ of marathon finishers positive split
• Average slowdown: 10-20% in the second half

How to Avoid It

When Positive Splits Are OK

• Your first race at a new distance
• Tactical racing (responding to competitors)
• Extremely hilly courses with downhill start
• Fun runs where time doesn't matter

Remember: A slight positive split (< 3%) is normal and acceptable!