Interval training
 

So i am a horrible runner, but i can manage to run for 3 or 4 minutes at a time before i have to stop. My friend told me that this is fine because interval training actually helps you burn calories. my average workout is 30 minutes on the treadmill at a 5 incline alternating running and speed walking, is this effective or should i be concentrating on trying to run for 30 minutes?

Your friend is correct. It is very effective. There are some descently priced Heart Rate Monitors that can also give you a count on calories burned. Interval training is great for you and over time you will find you can run for longer periods. There is a website Couch 2 5k, this may help you out as well. Good luck!

yup intravals is the best way to build speed and endurance. There is a guy named Jeff Galloway who does marathon/ultramarathons using the walk/run method.

Ummmmm. OK, to a point, but ALL intervals ALL the time isnt the best way to build speed and/or endurance. Do NOT confuse what Galloway prescribes as the same as stopping after 5 minutes because you CANT run farther. This is NOTHING like the Galloway plan.

Doing intervals once or twice a week (depending on how many times you work out) is good. But on some of the other days you should try slowing down and extending the run portions. Say at least one day slow it down to a point where you can run 10 minutes instead of 5 and one day slow down as much as you need to to run the whole 30.

Now if you care nothing at all about improving your running, and all you care about is effective calorie burn you are probably doing ok, but intervals like this can be taxing to the body if done too frequently.