I tend to injure myself when I start running again because I push myself too hard too fast. So far I've been blissfully injury and twinge free, and that makes me wonder if I can start pushing myself a bit harder...? I'd planned to do another 20 min run today, then take my rest day, then do 30 min for the next 6 days, but I'm wondering if maybe I can start throwing some longer runs in next week as well? Like 45 min or an hour? What do you think?
Fairnymph, you could run 6 or even 7 days a week if you wanted to but you need to ensure that you put in some rest days or cross training days, you can run flat out every time you train and long distances but as you know you'll just receive injuries.
When you first start running its important you take it slowly, your cardiovascular will become fitter well before your muscles and bones have adjusted to the rigors of road running.
You need to go through the process of "road hardening" and build up slowly. It can take years, litteraly.
It sounds like you've been running for a bit now and you've got the basic middle distances into your weekly routine.
So perhaps work out a running plan like this:
Monday - Run
Tuesday - Recovery Run + Crosstrain
Wednesday - Speed Session (Fartlek, Interval Training, 5km at 90% race pace etc)
Thursday - Recovery Run + Crosstrain
Friday - Run
Saturday - Long Run
Sunday - Rest/Crosstrain
Your hard runs should be done just that, hard. But your recovery runs should be taken VERY much like a recovery run, don't go out there and run anywhere near your race pace, simply use the K's to keep your legs active and your heart rate consistant. You should be able to hold conversation while doing these runs, if not, you're running too fast.
Whats important is to always warm up and cool down, particually hamstring stretches, calf stretches and glutes.
Your injuries may be related to incorrect shoes, poor gait/biomechanics or worn shoes.
Be sure to replace your sneakers every 600km, even if the upper looks relativley new the sole is often compressed or worn and does not offer proper support or shock absorbtion.
My shoes are hammered after 600km and when I was in marathon training (which I will be again soon) I used to churn through a new pair of shoes every 2 months just about, and they were definatley used past 600km.. probably more like 800-1000 and I just started getting injured.
It's a good idea to find a specialist running shop who can accuratley measure your gait on a treadmill and offer you good shoe advice. Without this analysis, unless you have a very natural neutral gait (ie no over pronation or supination), you'll probably be prescribed the wrong shoes or end up choosing shoes that lack the functionality you need and are just purchased because they look good.
If you're finding you're experiencing injuries and you do have the right shoes (or assume you do) it may be a good idea to visit a sports podiatrist to get your gait analysed professionally. You may need orthotics or perhaps just different shoes.
Just remember, first train for distance then for speed. Take it slowly and you'll be fine. It sounds like you have some pretty good concrete progress there so I'm sure you can start increasing your distances, in particular adding a 15-25km long run on the weekends.
With the sort of training you're entering at the moment you'll be fine to compete in long distance races like half marathons and full marathons.
Don't let anybody tell you that running is bad for your body, you just need to listen to your body to ensure that you don't injure yourself.
The major caveat for most runners is that they just become tollerant to pain and often run through injuries (myself included) just making them worse which leads to other injures. If you experience chronic pain while running, stop, walk/taxi/drive home and see a physiotherapist. Don't risk it, its not worth it.