Researchers have found that muscle power, reaction time, and aerobic capacity are all at their peak later in the day. Core body temperature also rises in the late afternoon, loosening up muscle fibers, which might leave runners less vulnerable to injury. Plus, Fliegelman says, the day's meals have replenished the carbohydrate stores necessary to fuel quick bursts at the track or the "comfortably hard" effort of a tempo run. If you can't swing late-day speed sessions, do them when you can: "They're going to have the same benefit for fitness and race preparation even if you might not be able to go as fast," says Youngstedt.
Stagger Quality Sessions
Different workouts tax different energy systems. Which means you don't have to be completely recovered from say, speedwork, before doing a tempo run. Generally, most runners can schedule dissimilar quality sessions two to three days apart. The key is to allow enough recovery time between similar workouts.
More: The Pre-Race Meal
According to Olympic marathoner Pete Pfitzinger, coauthor of Advanced Marathoning, seasoned runners generally need a minimum of five days between speed sessions, four days between tempo runs, and four days between long runs; less-experienced runners may need five to seven days between each. "People sometimes cram too many quality workouts without enough rest in between," says Fitzgerald. "Their bodies are in a constant state of borderline overtraining, so they don't adapt and they don't improve." If for some reason you must do two hard workouts in a row, take two consecutive recovery days—cross-train, rest, and/or run easy, says Pfitzinger.
Take the Long View for Races
"It's a gradual progression, over weeks and months, where things get more difficult and more race-specific," says Fitzgerald. Build in a recovery week every three to four weeks, and avoid burnout by scheduling no more than four to six weeks of track sessions. Prior to event day, do your final long run seven to 21 days out (depending on race length) and your last race-specific speed workout four to 10 days out. The more experience you have and the loftier your time goal, the closer to race day you can do final key runs, says Fliegelman.
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