based on this dose-response curve:
Seems like you’re basically picking up adaptation for free by adding even just a short, easy 30 minute ride at the end of the day (assuming you did your main ride in the morning).
might not be a lot, but it’s free, no downside. As long as you keep it easy it won’t even impact your next-day training (negatively, that is). What say?
I have and do try and incorporate two a days every now and then. The morning is the interval training and afternoon/evening is the Petite type of workout. Almost a recovery workout but aerobic. I have found twice a week is my maximum I can do. But doing two a days you do rick failing the third interval training day. I found that out the hard way and blew up spectacularly.
fair. i’d plan to introduce this little by little
That’s a solid plan, try it once a week, then build to two a week. Remember recovery is as important as the training itself.
I did find it useful when I was doing stage races, back to back stages, one race was a TT and a RR in one day.
As mentioned above, those are extremely useful if you’re planning on doing back to back races. You do have to make sure that you already have a very solid base before you go there.
Triathletes do two-a-days nearly every day…albeit usually with different sports.
As your fitness builds, adding in a second, endurance-paced ride is an excellent way to bump TSS and training time for the week.
@Power13 that’s exactly what I’m thinking: easy, not detrimental (if done right) way to add endurance TSS each week, a little bit more, little bit more, backing it off as needed.
Part of it is training smart, another part is just getting the work in.
I do quite often. I am doing the LV plans as I cant do it every day so on Tuesdays and Thursdays I do my main workout in the morning. In the evening when the wife is at college and the little one is asleep I do a second endurance ride (1 hour like petit or similar). It doesn’t fatigue me particularly and works well. Enough time between the two workouts (I do my morning workout at 5 am) and gives me plenty of rest days.
All commuters do!
Why back around the turn of the century, I had a new housemate who asked if I ever worked out twice in a day. I had been in triathlon for a few years and responded, “yes, my ‘off’ day was when I only did one workout in a day.”
My commute adds generally an extra 30tss a day, or if I want it to can be an extra 60TSS
Same as some others, 30 Min Commute morning, 1-1.5 Hour workout at lunchtime 30 min commute home.
Also last year my coach had me doing Sprints in the morning and Vo2 Max in the evening twice a week (With no other intervals in the week). About 12 hours between the intervals. and 2 days between training days.
Last year I used to do a morning zone 1 ride of about an hour, three times a week. Total volume was like 16h/week.
I think it helped building my aerobic base faster. Also, free endorphin.
And if you’re a commuter and a TR user, like myself and no doubt plenty of others here, then you do 3-a-days 
When I did two-a-day I was also commuting, so I guess I was a four-a-day. 