You’ve probably done plenty of double workouts—swim in the morning, run later in the day—depending on your experience in the sport. Although there’s no substitute for an all-at-once long workout because of the race-specific stimulus it provides, there may be a few reasons to do a single-sport double workout, especially with running. Some USAT coaches weigh in on when and why they use this two-a-day technique.
If you’re new to longer distances
Swimmers start doing double workouts to build volume starting at a very young age. “Two-a-days are in my regular bag of tricks, especially when I am building someone up for longer distance running,” says Dominion Cycling and Tri Club coach Trey McKinnon of Virginia. “I will have athletes do an easy run in Zone 1/2 in the morning of about an hour, followed by a harder or slightly longer run in the evening, or maybe just keep both at the same level and distance/time.”
If you’re strapped for time
Some coaches, such as Andrew Dollar of Tennessee’s FTP Coaching, believe long runs are best situated midweek. “For some athletes, this poses a slight problem to the work-life-hobby balance,” Dollar says. “On occasion, we will have the athlete perform 60–90 minutes in the morning and follow up with a shorter 20–30-minute run in the evening. The cumulative effect on the body is still an effective two hours of running.”
Jennifer O’Donnell-Giles, an exercise physiologist, coach and sports dietitian in Texas, prescribes split long runs or rides for her athletes with super busy schedules. “Ideally to train for longer races one needs to train as they will be racing—all at once,” O’Donnell-Giles says. “But when that’s impossible to do, a double workout is definitely an option, and one can gain improved cardiovascular results from doing so.”
If you’re trying to avoid or come back from injury
Many runners wind up with overuse injuries such as IT band syndrome, shin splits and tendonitis. Splitting apart a run may be a safer way to build up endurance and maximize recovery. “A 30-minute run might be a bit too aggressive for an athlete returning from injury,” Dollar says. “However, the same athlete may easily tolerate 15 minutes in the morning and 15 minutes in the evening—yielding them 30 minutes of volume.” The recovery time between the runs will help inflammation subside, allowing the athlete to bounce back easier. Another option may be to do the continuation run—start your long run in the evening and finish it the morning after.
If you’re building mental stamina
A long run in the morning followed by an evening 15–20-minute recovery run is challenging but great for long-distance race simulation. “Since the athlete is already in a glycogen-depleted state, the run will require deeper glycogen utilization and additional mental and physical stamina to complete—skills that are particularly important in endurance racing,” Dollar says. He recommends that your secondary run be performed at an “embarrassingly slow pace” and be no longer than 20 minutes. Another option is to do your Saturday long ride followed by a transition run in the morning, then add in an evening 15-minute recovery run.