Negative Split
A negative split means running the second half of a race faster than the first half. Learn how to execute negative splits and when this pacing strategy works best.
Quick Answer
Negative Split — A negative split means running the second half of a race faster than the first half. For example, running the first 13.1 miles of a marathon in 1:50:00 and the second half in 1:45:00. This strategy conserves energy early for a stronger finish.
What is a Negative Split?
The term "negative split" comes from the difference between half times:
Split Difference = Second Half Time - First Half Time
- Negative: Second half faster (difference is negative)
- Positive: Second half slower (more common)
- Even: Both halves equal
Example:
- First half: 50:00
- Second half: 48:00
- Split: -2:00 (negative split by 2 minutes)
Why Negative Split Works
Physiological Benefits
| Advantage | Explanation |
|---|---|
| Preserves glycogen | Slower start relies more on fat oxidation |
| Delays lactate | Stays below threshold longer |
| Better thermoregulation | Body warms up gradually |
| Reduces muscle damage | Early restraint protects muscles |
Psychological Benefits
| Advantage | Explanation |
|---|---|
| Passing runners | Motivating to catch others late |
| Building momentum | Confidence grows as you speed up |
| Avoiding despair | Never experience the painful slow-down |
World Records and Negative Splits
Many world records have been set with negative splits:
| Race | Record Holder | 1st Half | 2nd Half | Split |
|---|---|---|---|---|
| Marathon | Eliud Kipchoge (2:01:09) | 60:33 | 60:36 | +3 sec (near even) |
| Marathon WR before | Various | Often negative | - | - |
Elite marathoners increasingly favor even to slightly negative pacing, typically within 1-2% of even.
When to Use Negative Splits
Best For:
| Scenario | Why It Works |
|---|---|
| Marathons | Long duration rewards conservation |
| Half marathons | Distance allows for pacing strategy |
| Hot conditions | Prevents early overheating |
| Hilly courses | Allows recovery on early hills |
| Inexperienced racers | Prevents blow-up from going out too fast |
Less Effective For:
| Scenario | Why |
|---|---|
| 5K races | Too short; can't make up much time |
| Criteriums/track | Variable tactics dominate |
| Elite short races | Competition forces aggressive starts |
Read more: 5K Negative Split vs Positive Split.
How to Execute Negative Splits
Step 1: Set Conservative First Half Pace
Start 5-10 seconds per mile slower than goal pace:
| Goal Pace | First Half Pace |
|---|---|
| 8:00/mile | 8:05-8:10/mile |
| 7:00/mile | 7:05-7:07/mile |
| 9:00/mile | 9:10-9:15/mile |
Step 2: Hold Steady Through Midpoint
- Resist urge to speed up when feeling good
- Trust the plan
- Focus on relaxation and form
Step 3: Gradually Increase After Halfway
- Miles 14-18 (marathon): increase to goal pace
- Miles 19-26: slight negative splits
- Final miles: fastest of the race
Example: Half Marathon with 1:45:00 Goal
| Miles | Target Pace | Split |
|---|---|---|
| 1-3 | 8:10/mile | Controlled start |
| 4-7 | 8:05/mile | Settling in |
| 8-10 | 8:00/mile | Goal pace |
| 11-13.1 | 7:50/mile | Push finish |
Use our Half Marathon Pace Calculator to plan splits.
Negative Split vs Even Split
| Strategy | Pros | Cons |
|---|---|---|
| Negative Split | Feels strong at finish, safer | May leave time on table |
| Even Split | Theoretically optimal, predictable | Requires perfect execution |
| Positive Split | Common in racing | Often indicates starting too fast |
Research suggests even pacing is slightly faster than negative splitting, but negative splits are easier to execute and reduce risk of blowing up.
Common Negative Split Mistakes
1. Too Conservative Start
- Starting way too slow wastes time you can't make up
- Aim for 5-10 sec/mile slower, not 30+ sec/mile
2. Surging Too Early
- Building too quickly mid-race leads to late fatigue
- Patience until 60-70% of race distance
3. Not Practicing
- Race day isn't the time to try new strategies
- Practice negative splits in training runs
Training for Negative Splits
Progression Runs
Start easy, finish fast:
| Duration | Pace Breakdown |
|---|---|
| 60 min | 20 min easy, 20 min moderate, 20 min tempo |
| 45 min | 15/15/15 with increasing pace |
Negative Split Long Runs
| Miles | First Half | Second Half |
|---|---|---|
| 16 | Easy pace | 10-15 sec faster |
| 18-20 | Easy pace | Final 4-6 miles at marathon pace |
Common Questions
How much faster should the second half be?
For optimal results:
- Marathon: 1-2% faster (30 sec to 2 min)
- Half marathon: 1-3% faster (20 sec to 1 min)
- 10K: Near even or 1% faster
Is negative splitting always better?
No—perfectly even pacing is theoretically fastest. But negative splits are:
- More forgiving of errors
- Psychologically rewarding
- Easier to execute in variable conditions
What if I'm already behind pace at halfway?
Don't try to make it all up immediately. Gradually increase pace to minimize the damage. Trying to "bank time" in the second half after a slow start rarely works.
Can I negative split a 5K?
It's difficult because:
- Less time to make up ground
- 5K pace is already near threshold
- Start-line positioning matters
See 5K Pacing Strategy for Beginners for 5K-specific advice.