If you’re preparing for a longer race (10K to marathon), time trials at shorter distances are a painful but efficient way of maintaining speed. Low-key road races work, too, but time trials require no entry fee, and you can pick the date that works best. For marathoners and half marathoners, aim for between 5K and 8K; if you’re preparing for a 10K, you can go as short as a 2K. Include one or two speed tests in a buildup, with the last at least two weeks prerace. Unlike a dress rehearsal, the goal isn’t to maintain a particular pace – it’s to suffer in a way you don’t during regular longer-distance training. Fighting through the symptoms of anaerobic fatigue will help train your body to handle slower paces more efficiently. To maximise the effect, err on the side of starting aggressively – at least 2 percent faster than your best recent time at that distance.
Time trials exist in a gray zone between workouts and races, and the distinction is blurriest when you add a time trial to a larger interval workout. For example, to prepare for a 5K, you might run a 2K time trial, recover for 10 to 15 minutes, then do a ladder of 1200, 800, 600, and 400 with 2:00 rest, starting at 5K pace and getting faster. The extra volume will stimulate more fitness gains than a speed test, but it requires more recovery – schedule it three to four weeks before your race.
The time trial should still be run all-out, so try to forget about the rest of the workout until you’re finished, and be flexible about the pacing and number of reps – don’t give yourself excuses to save energy. A time trial isn’t a race, but it should feel like one.