My experience with doubles which is about 5 years is that it really doesn't matter which one is hard and which one is easy. What does matter in my opinion is how many runs you have per week that are above aerobic threshold.

My experience is anything above two is really pushing the boundaries of getting injured, hurting your bike training, or preventing you from getting the most out of your above threshold workout.

I think doing your second run after your tr session is fine if that works best for your schedule from a time/logistics stand point. Just don't go around telling people that your run kicks ass because you do bricks. That's frowned upon around here and has been proven to be myth hundreds of times.

Lastly, running doubles is very personal and can be different for many people and can even differ for the same person from week to week. It's like a box of chocolates. You never really know what your going to get with that second run until you get out the door and get going.

You sound like your pretty intrinsically motivated so maybe incorporate one double per week with a 30 min run at lunch and one in the evening after your tr session. If you get a good response from that and more importantly are enjoying it maybe add a bit of progression to the lunch run to 45 mins and so on.

Great reply by the first responder. I love running doubles. As someone who prefers a longer warmup, I find I always run better in the second run and so I always make the second run the more intense. Therefore my first run is typically slower and incorporates more warm up focus, maybe with butt-kicks, high-knees, etc. to work on range of motion. If the first one is fast in any way, it's a progressive run with a slower start and build to speed. After an easier first run, I find that in the later run I can usually push the pace and run fast and relaxed after less than half a mile. Depending on how much mileage I can handle, I may do 2-4 miles for the first run and then 3-6 miles with tempo, Tabata, or intervals for the second. If I am really peaking, I might do "6 & 6" or "7 & 7" where I run the same 6 or 7 miles route twice in a day – a slow-to-solid pace for the first, and then really pushing tempo in the second run. If I can do those runs I know I am ready for a fast 10l or 13.1.

So figure out if you're the type who can use the first run for a fuller warm up or "junk miles", and then still can feel speedy in the second run. Slower first run, faster/more intense/hills second run. The exception: the second run as a brick might not feel great but would be worth trying, and might feel sluggish for the first mile but then let you "click" into some form thereafter. That makes for a long day though (early run, then bike-run-brick).

Thank you folks for the response. My plan to run double as brick was only due to logistics. Made it easier to plan as I was already finishing a workout and can hop on the treadmill quickly after. My other weekdays are for evening swim (2x), hockey at times and perhaps some lazyness too. My prime time to work out are lunch hour and evening after 8pm. Weekend are hit and miss as I have commitments with family but I am pretty consistent weekdays.

I do have access to very nice hills near work and can use my lunch time to go hard too. (Intervals or tempo run) But I'll take some inputs here and start slowly to see how I feel first.

I know I know... Waking my ass up to do a quick run in the morning would solve some issue here for sure and perhaps running to the pool as another thread allude too as well..