just stop now wrote:
"My training the last 2-3 weeks consisted of ~60 mpw but also ~5-6 60-90 min intense cross-fit sessions per week."
That's an insane amount of crossfit for something that you intend to just be an accessory to your training.
Yea and I did have to eat a lot again and go to the toilet many times a day but it was effective. I gained 0 muscle mass, but I felt stronger aerobically in running and was able to set some PRs. I have decent innate speed but for gaining endurance I need to do a LOT LOT LOT.
Also they are often very fun, 1500m rowing warm-up is great (I'm so good at it you can hear the cable almost break), stuff like TRX row, wall balls, kettle bell swings, kettlebell snatches, sled pull/push, farmer's walk, jumping lunges, thrusters (with bulgarian bag or as front squat to push press with bar), goblet squats, ... are all solid exercises and there is never a break in 60 minutes so even I get exhausted and feel it. And it's always a group doing it, I ran alone the last 2 years almost you get very lonely when you log so many miles alone the forest. XFit gave me something new.
Today's run was already much better again, but I did have to sleep the whole day. With a 40 hour job I wouldn't be able to keep this up. Anyway, I think 2x hard lifting by myself and 1-3 extra sessions (crossfit or group lifting) will be a nice addition to the running. I used to do swimming and cycling before as cross-training, so I'm sure my body can handle it and if it works, it might even make me stronger as a runner.