I've been working with a personal trainer for the last four months and I think it makes all the world of a difference. I used to do a lot of cardio on my own when I was younger, but I stayed as far as I could from anything involving long distance running, so this is all new to me. Thus far I've been doing it all on treadmills because I want to maintain a steady pace and because I need to stare at the clock to know when the suffering is going to stop, but I'm expecting we'll be going on morning runs through the forests soon enough. It's incredibly helpful to have a guy right there cheering you on and watching you push towards new milestones, and they watch your running technique up close to analyze it in detail and give you invaluable pointers.
When I started out, I hadn't been physically active in half a year, and I'd been putting on a lot of weight after having finally managed to stay almost bone thin for a couple of years. We've been going through a lot of different exercises every week involving cardio and weight lifting, but for the first month the cardio component mostly involved light walking (including sideways and backwards to build ankle strength and balance). After roughly a month I had my first 5 minute run at 5mph plus 10 minutes of up and down tempo (1 minute walk, 1 minute run); I was drenched in sweat, barely made it to my car afterwards and when I sat down it felt like my shins were on fire. The rest of the week we went through some other types of workouts so my shins had some time to rest, which was pretty important. The next time I ran, there was already a whole slew of corrections my trainer had me make to my posture and the way my feet hit the track, and even now 3 months later he's still having me make adjustments.
In about 3 months I've progressed from a fairly clumsy "thump thump thump" stride to a nice smooth, efficient glide going heel to toe. Takes a heck of a lot of pressure off the shins, and it really helps to stretch first and loosen things up beforehand, plus ice down anything that swells afterwards. My shins were totally killing me for the first several weeks, and my right knee was really bothering me, but with the combination of improved stride, stretching and body adapting, the knee isn't even an issue anymore and the shins barely feel a thing afterwards. I'm now holding a 6.5mph pace for 30 mins at a time and my tempo runs alternate between 4mph lows and 8.5mph highs without causing much difficulty, my heart rate seems to recover really fast. While there are other routines I go through every week, I've only been running once or twice a week so far because new aches and pains keep popping up every time I push to a new milestone.
Latest annoyance is a tension in my right thigh/hip that seems to be exarcebated by cold weather, been bugging me for a few weeks now and the running tends to aggravate it somewhat. I just bought myself a heating pad, as my trainer told me to start using on the muscle before working out, and I'm stretching it and icing it more to try and keep it relaxed before and after runs. After 30 minutes of running now I still have plenty of gas in the tank, so I'm hoping to push it to 45 minutes soon, and to do it more times every week, but we're also trying to give my body enough of a rest so it has a chance to adapt to all the new strains.
I'll tell ya, it's a really uniquely good feeling when you see some fit yoga chick running at the same pace beside you and she gets tired out way quicker.
My personal advice: Drink tons of water before and after, and don't eat too much in the morning or the night before because it's really uncomfortable to run in the morning and still be digesting last night's dinner/snack. Don't worry about painful side stitches if you get them, just focus on maintaining a steady, comfortable pace, breathe slowly and deeply through your stomach, and they should disappear after a few minutes. Stretch and warm up for at least 5 minutes before you start running, and then have a good 5 minute cool off and stretch some more when you're done.
My trainer's been really thrilled with my progress and thinks I must have been a runner when I was younger, but I think he's just got a really good program and he's always switching things up to try and shock my body into adapting in new ways. I think it's definitely one of those things where your body just has to pick it up just like when you first learn to draw, and then you'll start to see rapid improvements as you get more into it.