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.”