You may have heard or read about the Furman Institute of Running and Scientific Training program that has been documented on-line and also in the recently published book Runner's World Run Less, Run Faster: Become a Faster, Stronger Runner with the Revolutionary FIRST Training Program. The program is based on three weekly runs (interval session, tempo run and long run) complemented with two (or more aerobic cross training sessions). The runs are done at prescribed pace in order to achieve speed improvements, improve lactate threshold and VO2max.
I was very excited when the book came out, because the traditional "run every day" program does not work with family, triathlon training, full time job, and all the other stuff that life throws at you. I decided to start the F.I.R.S.T. training plans for the 5k race right after the triathlon season was over (after the September 23rd race). Unfortunately I injured myself in the week before my last triathlon race (a stupid mistake when I stepped off of the running treadmill) and I had to take things lighter over the next few weeks to heal the ankle sprain. For the training I used my 5k PR from the September sprint triathlon to determine the training paces. The book recommends to use recent 5k race results or longer distance race that is then converted to the 5k equivalent.
First training sessions felt quite hard as I used to run little slower even on hard days. So it took some adjusting. Especially the interval session was hard to do and I found myself feeling sick from my stomach after the sessions. I did majority of the interval sessions on treadmill to force myself to stick with the prescribed pace for the whole interval duration. In the recovery part of the interval I keep moving, but quite often need to resort to fast walking to catch my breath and sustain the next interval work. The tempo training is fairly manageable and I alternated it on the treadmill and outside (depending on the weather and the time constraints). The long runs are generally fine as the pace is little slower than tempo, but they get harder in the last 1-2 miles. In all the sessions I found myself checking the watch more often in the last part of the session. I complement the running with bike, swim and strength training to reach the planned number of training hours in the week (determined by my training plan on trainingpeaks.com).
So how did it all worked for me. Let me just say that my 5k PR improved from later September to mid November from 22:15 to 21:35. That is 40 seconds improvement on the 5k race which looks good to me considering that I was unable to train through all the 5k plan sessions due to the injury. I lost about 2.5 weeks when I was unable to run at all or I had to run slower than prescribed pace. Later in December I ran another race - 5mi in 35:10 which translates approximately to 21:15 for 5k. So there is certainly good improvement after just few weeks of training. I continue using the F.I.R.S.T. plan for the upcoming half marathon. I hope the speed gains will continue and I'll be able to run the half in under 1:45 (well maybe even faster). We shall see how the speed translates from the short distance race to the longer distance race.