And I never combine the two. When I run, I want to give it my all and I love to do it. I do not want my performance dulled by muscle soreness.
Of any run, the first mile can feel tough, as you work through muscle fatigue and getting into your stride, getting any kinks out and getting into your breathing rhythm: why would I want to compound that by having weight trained my legs beforehand?
I say no. But, it is a question of personal preference. I think it depends upon whether you are running for fitness, in which case combining is fine and may be what you want, or running to become a better runner, in which case weight training legs on the same day will compromise performance and improvement IMHO.
Clare