
Originally Posted by
CityOfChicago
If your goal is improved 1.5mi time, then ditch the 2 mile runs. You're wasting energy that could be spent elsewhere. Again, this is if your goal is that 1.5mi time.
I'd add some shorter runs (1mi to 1.25mi) that are interval-based. Do you run on a track? If so, sprint the straights and jog the curves. If not, you'll need to do it by time(easier if on a treadmill, otherwise wear a watch). Try a 1:3 or 1:2 ratio - "sprint" 30 sec / jog 90-60 sec. The exact time syou neeed to base on your current fitness level. You may find it best to sprint 60sec/jog 120sec, or you might need to "sprint 30sec / jog 90 sec.
This interval training will get your HR higher, increase capillary density (the number of blood vessels in you muscles) increase mitochondrial density (the number of organelles that produce energy in the muscle cells), and increase lactic acid levels in the muscles. The active rest will allow the muscles to recover a bit and metabolize the lactic acid, removing it from the muscles. Lactic acid tolerance is one of the main limiting factors in performance. As it builds in the muscles, it literally begins to prohibit further work. By exposing your muscles to repeated high levels of lactic acid, they 1) become more tolerant of higher levels and 2) become more efficient removing/metabolizing it. Also, the higher intensities will force adaptaions between your lung cells and blood, allowing for more O2 to be absorbed and transferred to the working muscles.
Over time, aim to increase the length of time you spend "sprinting", subtracting it from your time 'jogging'. ie: if you do a 16min run, with 30 sec sprint 90 sec run, work on getting 60sec/60sec. Once this 1:1 ratio is achieved, increase the speed of your "sprint" and "jog", and go back to the 1:2 or 1:3 ratio. Clear as mud?
Also, apply these to your regular 1.5mi runs. Example: Lets say you currently run a 10min mile (I know your's faster a bit, but let me make the math easier on myself). Your intervals may be something like 7min mile/12 min mile - you'll have to figure out the speeds that work for you. As you start getting better at this interval, and closing in on that 1:1, increase the speed of your 1.5 mile runs, as well.
With all the longs runs you've been doing, you should already be in fantastic aerobic shape. These changes wont effect that. Also, with such a strong aerobic base you should see changes very quickly - I mean like nearly every workout for several weeks quickly. Work those intervals hard. "Sprints" should be hard runs that gas you , while "jogs" should allow you time to recover so that you feel ready to "sprint" again.
Sorry for the long post - hope this is helpful.