Q: Is it harmful to my training program to work out twice a day? I love to go to interval and conditioning classes, and I also want to run on a routine basis. How can I gauge, besides soreness, how much is too much? – Sherry, Chicago, IL
A: Traditional two-a-days are usually unnecessary for recreational athletes, but sounds like the way you're doing it—as a means to essentially divide your training into more manageable parts—is an effective approach. Just keep in mind that even if you're doing two short workouts a day instead of one long one, you'll need to eat prior to and after each session to give your body energy and help it recover from the stress of training.
As for more competitive athletes or folks who have more time to rest and recover during the day, aim to keep your training sessions to 45 minutes or less with ample time between bouts for recovery. For instance, if you train once in the morning and then later in the afternoon, try taking a 20 to 30 minute nap between 1:00 - 2:00 PM to optimize recovery before the second session. Execute your movement skills and strength work in the morning and do your Energy System Development (or interval work) in the afternoon.