Running Twice A Day
Is it okay to run twice in one day... say, one 2 mile run in the morning and a 4 mile run in the evening?
Is this okay for training for speed and endurance or does it harm my muscles?
Answer by Dominique:
Thank you for your question.
In principle there is nothing wrong with running twice a day.
However, many runners run twice a day when it is not really necessary and it is not necessarily better for you. So you might have to revisit your motivation in doing "doubles".
Is it because you think you need to or is it the only way for you to increase your mileage due to time constraints or something else?
Some pros and cons and facts about doubles:
1. Single runs are better for base building
As far as endurance and establishing a base is considered it is better to run six miles at once, than to break it up in a two-miler and a four-miler. As a general rule it is better to add the extra mileage to your single run, than to break it up. Obviously for high-mileage runners there is a breaking-point where it is more beneficial to run twice a day to allow the body to recover more.
2. Shorter doubles allow faster training
Two fast three-milers are easier to "digest" than a fast six-miler.
3. If doing them, add doubles gradually to your running program
Principle number one of running is / should be that you should increase mileage safely. Same with doubles. Start with a short additional second run and expand from there into longer second runs and/or more second runs.
4. Try to avoid two tough runs on a day
A long run in the morning and a tough tempo session at night is a recipe for disaster. Keep to the hard/easy principle and as a starter, I highly recommend to make both runs easy runs to avoid injuries.
Hope this helps a bit in giving you some guidance. Running twice a day is definitely a valid option for some runners. But when you do it, do it with care and as always, make sure you listen to your body so you know when you stress it too much.
Also make sure to check out my running training section which includes many more running tips to become a faster, better runner without necessarily having to do doubles.
Good luck with your running.