A negative split means completing the second half faster than the first. More importantly, it represents disciplined energy management.
Why runners fade
Starting above sustainable effort increases carbohydrate use, heat and muscular cost. The early gain is usually smaller than the late loss.
Control the first kilometres
Race pace often feels easy at the start. That is not a signal to accelerate; it is the expected feeling of a well-chosen pace.
Use effort and conditions
Wind, elevation and temperature can make exact pace misleading. Maintain appropriate effort and allow pace to vary.
Practise in training
Progression runs, fast-finish long runs and controlled tempo sessions teach the body and mind to increase effort late.
A realistic target
The goal is not always a perfect negative split. Even pacing with a strong final section is often the best practical outcome.
Decision point
Enter the final third with options. A good race plan protects the ability to decide rather than forcing survival.
Training decisions should be adapted to your history, schedule and recovery. General information is not a substitute for medical advice.