rda,
As a new triathlete you'll find that there are three components that you will really need to focus on with your training in each discipline:
- Enough mileage
- Enough intensity
- The right kind of intensity at the right time of year (peridoization)
For long term development, your focus is in two areas (in this order):
1) Increasing your mileage.
-You will find it VERY difficult to make any great gains running only 2-3 days a week. Because of the nature of running being an impact sport, your wokouts will likely end because your legs are beat up, not because you are too tired to run any further. In the pool or on the bike, you can push for several hours in a single workout. You simply can't do that as a runner. Therefore, you must try to get in many shorter runs.
-I recommend ONE run a week that is as far as you can reasonably handle without needing more than a day to recover from. The rest will be anywhere from 15-45 minutes. A goal of 5-6 runs a week is, IMO, ideal for most struggling runners. This could mean you simply run 45 minutes once and then 5 15 minute runs where ever you can squeeze them in. The runs should be relatively easy (but not a lollygag). I have had great success doing this myself and with the athletes I've advised. In addition I've heard of great successes from coach Brian Stover and Mitch Gold giving the same recommendations to triathletes.
2) Increasing your lactate threshold
-This is done through LONG sustained efforts, not short fast intervals. Once you have pushed yourself as far as you are willing to spend the time doing (as a triathlete, TIME will be your limiting factor, not ability) then you want to gradually begin trading in those easy efforts for harder long efforts. You may get to 2 hours a week.....3 hours.....5 hours....whatever you set for yourself (I recommend *most* people a minimum goal of 3 1/2 - 5 hours of running a week. But if it's shorter due to life constraints, then that is what you have to work with). These long efforts should be at a pace that you think you can run in a one hour race. It will most likely be about 25-30 seconds a mile slower than your 5K race pace. The efforts can extend up to one conitnuous 40 minute run (plus warmup and cool down) or be broken up into intervals with a 6/1 work:rest ratio (6 minutes hard, 1 minute jog). Shoot for a minimum of 20 minutes in one workout and a maximum (once you *gradually* build to it) of 60 minutes a week.
For short term development, your focus will be in these areas:
1) V02max intervals
-These are intervals that last 3-4 minutes in length with 2-3 minute jog in between. The total workout (the fast parts) should be a minimum of 18 minutes (untalented 14 year old girls) and a maximum of 28 minutes (very talented collegiate runners). This will raise the amount of oxygen your body can take in during a race.
-This workout is VERY stressful and has great short term benefits. However, everytime you do this workout you will be sacrificing potetential long term benefits that occur when training at longer/lower intensities. I recommend doing these for periods of 4-12 weeks at a time and for no more than 24 weeks total out of the year.
2) Shorter, faster intervals with longer rest.
- These will be intervals of 30-90 seconds in duration with double the amount of rest. A workout should consist of between 6-12 minutes of fast running. This will help improve the neuromuscular component of running (like a boxer hitting a heavy bag....he learns to punch quicker, harder, and more efficiently).
- This can be done as a second workout during the week in conjunction with your V02max workout.
3) Hills
-Similar to the short, fast intervals. You can do these in place of those or as a thrid workout during the week. It will take time to see which kinds of workouts you respnd better to.
Notes about periodization:
I prefer to 1st build an endurance base, 2nd work on lactate threshold, and then 3rd build speed through hills and intervals. It’s a really good idea to run the longer fast efforts 6-9 months out of the year and even carry them well into your “speed phase.” Once you get comfortable with these you can also work in some hills as a second workout each week.
To answer your question:
If you want to get faster in ONE month, then you are talking about short term improvement. You will benefit more from doing those workouts. However, on a year to year basis you need to spend the BULK of your time training from the long term list.
For more info, see the link below.