A friend once suggested that I’d never improve my times on our personal cycling time trial course if I didn’t record my “splits” and then work harder on the sections where my pace slowed. So I divided the course up into sections, or splits, and used a sports watch with a lap timer to record my performance through each. Then I manually, obsessively entered the splits into a spreadsheet. Over several weeks it became obvious where I needed to try harder. Everywhere.