I'm not much of a runner currently, but can probably run 10 km in 55 min. I weight-lift three days a week and don't want to cut it down.
How should I design my running schedule so as to optimise my goal time in a half-marathon in three months?
Physical Fitness Stack Exchange is a question and answer site for physical fitness professionals, athletes, trainers, and those providing health-related needs. It only takes a minute to sign up.Sign up to join this community
So you're primarily a lifter but want to compete in a half-marathon.
It sounds like you're control but here's what I would suggest.
If you're lifting 3 days, that leaves 4 days for running. I'm current training for a half and running every other day. You'll do just fine on a plan like that.
Search for programs Online. Runkeeper has som e paid training classes which may work well for you if there's one that matches the amount of time you have. Runner's World has a cool iPhone app that lets you customize a training program based on your goals and how long you have to reach them. It's also cheaper.
Update: the last week before the race, go easy with all training, including lifting.
There are a couple of things you need to ask yourself before you can get a solid answer. How much time do you want to/do you have to commit to the running training? If you only have 4 days, I'd suggest running on the days that you do not lift as mentioned above. If you want some overlap (to provide you with a recovery day) my philosophy has always been to lift after running. If you run fresh you may have different form if you just recently completed exercise of a different fashion. Running tired or fatigued (especially if you lift with your legs) can cause tightness, which can alter form or gait. If you want to train its best to keep good form for injury and muscle memory reasons. IF you have to lift first thing in the day, I'd reco waiting until the late day to run if possible.
Then again if you believe you are not prone to injury and do not want to sacrifice lifting form from possible fatigue from running feel free to switch. If, however, you decide to do hard running workouts (tempo runs, track workouts, I'd really reco you lift afterwards)