To negative split is to go faster in the second half of a race leg than in the first. In reality, however, due to the layout of courses, winds and other factors, it’s more accurate to negative split your effort, applying more effort to the second half of the bike. This is a powerful strategy for three important reasons.
Start slow so you don’t blow. Nearly everyone experiences a significant disconnect between heart rate, effort and rate of perceived exertion (RPE) in the first 20–60 minutes of the bike leg. That is, it may feel easy, like you’re not working hard at all, but your heart rate and effort applied to the bike are telling you something quite different. It can take several minutes for heart rate and RPE to reflect your effort level. By committing to backing off in the first third or half of the bike leg, you avoid the common mistake of working too hard without realizing it.