Running too much may negatively impact muscle gains/body fat %'s. Look at most sprinters versus marathon runners. Who has more muscle mass/lower body fat? However, it is like anything with training aerobic and resistance style; it is dependant on the individual. So you have been performing both, have you seen improvements? If yes, then stick with what's working. If its not working, cut back on some of your running days or modify your running program then see what happens.
You can always do the extremes, ie run your tail off each week, with 1-2 days of weights then perform nothing but weights 3-4x per week with only 1-2 days of aerobic exercise.
Good luck!
