"Its rather difficult to advise someone I have no real running experience with, but I will try and help by offering some insight.

First off, I assume you are training for a 1/2 or full marathon. I also assume this is your first endeavor into this type of training. I also assume you are an adult runner over 30.

Let me say this: speed work has "crippled" more beginning runners than I care to think about. Speedwork is meant to be the last stage of a training program. Kinda like the last 5%.
For beginning marathoners its a waste of time because they don't understand what it is or why they are doing it. Unless you are able to run 30+ miles a week for 10 weeks without injury, it will not improve your "speed" much, but may actually set you back.

I strongly urge you to adopt a solid base training phase of 10 weeks. Then progress into a phase of up tempo runs. Its good to train with someone a couple of days a week who runs a faster pace than you do. By running this second stage of training faster you will condition your body to run fast and push your cardio endurance up.

Now by looking at this speedwork session you enclosed, its for a mile pace of 8:12. that should mean that you have run a 52 min 10K race within the last 4 months. Am i close? If not, you should look over your plan again.

Let me break down speedwork.

It is used in the final phase of training to improve your VO2 max, sharpen your form, teach you to pace and teach you the mindset of fast running. You run an up pace for short distances/length of time to do this. By doing it in short bursts, you don't overtax your body or suffer build up of lactic acid to the point of inhabiting the next 48-hour training session.

Some definitions: If you think of a high school track as a reference. 1 lap around is 440 yds or a 1/4 mile. Two laps would be 1/2 mile, 3 would be 3/4 mile and 4 would be a mile. Now a metric measurement is a bit different to measure. There a paint marks on a high school track to indicate standard and metric measures. They are tough to decipher if your not familiar. so keep this in mind: Most runners will use 400 meters as a 1/4 mile, 800 meters as a 1/2 mile etc. It is a bit off, but the reason to use a track and set time is so you can refer to past efforts and current efforts using a standard length and time.

Let me break down the workout you list.

Your total mileage for this work out is 5 miles -- no more.

You would run 3 x 800 meters (2 laps) at around a 4:06 pace (8:12 mile pace). you could be 5 seconds faster or slower depending on how you pace yourself. HINT: use your watch. You know your gonna run two laps -- yoou should compete your first lap around 2:03ish, therefore you should run 200 meters (that would be directly across the track from where you start) at around 61 seconds. Using these checkpoints you can learn to pace yourself.

You will then jog one lap (1/4 mile) between. This pace should equal the pace of your speedwork lap - 4 minutes. This allows your heart rate to recover to about 70% of its max.

Now the total of your speedwork it as follows: 3 set of 800 meter with two recovery jogs of 400 meters each. This equals 2 miles. That leaves 3 miles total to be used for your warm up and cool down (1 1/2 mile or 6 laps for each) this should be run at an easy pace to warm up the muscles in the beginning and then to help flush the lactic acid out of the muscle tissue at the end. This pace should be around 2+ minutes slower than your predicted race pace.

Hope this begins to clear things up. Remember its not about speedwork as much as its about a solid base of mileage followed by training your cardio system to function more efficiently."