I want to run faster!

[AndrewL]

I ran easy 5ks last week and am doing 30 minute runs this week and looking to just increase by 10 minutes a week or so for the next few weeks. Would it be better to spend 60 minutes out there and do something like 4-5k / walk / 4-5k? I'm a little worried about an overuse injury after coming back from a fairly sedentary couple months so have been keeping it short, but would be fine with trying to push myself a bit more.