My Experience with Phase IV of Jack Daniels 5k-10k Plan

This spring, I’ve been training for a half marathon using the 5k-10k plan found in Jack Daniels’ book Running Formula.

I’ve previously written about my experience in Phase II of the plan, as well as my experience with Phase III of the plan. My goal race is Sunday, and I’m through my last workout in Phase IV, so I thought this would be a good time to reflect on how the end of the plan has shaped up.

Quick Review of the Jack Daniels 5k-10k Plan Structure

First, if you haven’t read one of the previous posts, let me describe the plan. If you’re already familiar with it, feel free to skip ahead to the next section.

It’s divided into four phases, and each phase is approximately six weeks.

Phase I is a base building phase. It’s not really a phase of the plan, as Jack doesn’t prescribe anything for you to do. But if you aren’t already in good shape, you should take six weeks to build up your mileage and prepare. I was in good shape coming off of a fall marathon, so Phase I wasn’t necessary.

Phase II focuses on speed. The main workout each week is an R-paced or Repetition paced workout. This is mile pace stuff, along the lines of 10x400m with 400m jogging recovery. The secondary workout each week is typically cruise intervals. Read more about my experience in this phase here.

Phase III shifts the focus to more race specific work. The main workout is now I-paced or Interval paced. This is typically 1000m or 1200m intervals at 5k race pace or a little bit faster. The secondary workout is still threshold cruise intervals. Read more about my experience in this phase here.

The final phase is a competition phase. There’s typically a light mid-week workout. Then there’s either a second workout on the weekend or a race. This phase is very fluid, and I ended up modifying it from what was written – but trying to follow the spirit.

Adjusting Mileage in Phase IV of this 5k Training Plan

There’s nothing specific in the book about mileage in this phase. The whole plan is kind of fluid in that respect. Jack assumes you’re running a certain range of miles – in my case, 60-70 miles per week – and it’s really up to you to determine how many to run in any given week.

Throughout Phase II and Phase III, I ramped up to 70 miles in a few peak weeks. My average mileage was about 65 mpw. By the end of Phase III, I was feeling the build up of fatigue, and I was looking forward to dropping my mileage a bit to get ready for some racing.

So my plan was to drop to 60 miles per week and hold it there throughout most of the phase. That’s worked out really well for me, and I’m feeling a lot more fresh throughout the week.

The only week that wasn’t 60 miles was the last week leading up to my goal half marathon. I decided to taper going into this race, and I ran 44 miles in the seven days leading up to the race.

The other adjustment that I made to the mileage was to incorporate some doubles. I hadn’t used doubles throughout the early part of the plan, and I hit my 70 mile per week goal with all singles. But this often meant mid-week workouts of 10 to 12 miles, and some easy runs that hit 8 to 10 miles.

In Phase IV, the shorter workouts were only 8 to 10 miles. Any other easy day that would have been over 6 miles, I split into two easy runs. A couple of these were 5-5 splits, and a couple were 7-4 splits. I liked the way these felt, and they helped me stay fresh while hitting the miles. This also let me front load some of the miles early in the week, so that I had some lower mileage days leading up to a weekend race.

Workouts in Phase IV of this 5k Training Plan

The weekly workouts in Phase IV are very toned down compared to what I’d gotten used to in Phase II and III.

In a typical week, this was simply 3 x 1 miles at threshold pace with 2 minutes of rest in between. I usually did a long warm-up before (~4 miles easy), and my total mileage for the day would be somewhere between 8 and 10 miles.

The first week, I killed this workout and ran the intervals at 6:40 pace. But the other two times I ran it, I was more comfortable running ~6:50 pace. The workouts were short and relatively easy, so they left me fresh for the weekend.

In one week, I replaced this with a more typical half marathon workout. I had raced a 10k that Sunday, and my mid-week workout was about a week and a half prior to my goal race. Instead of the easy 3×1 mile cruise intervals, I substituted a 14 mile long run progressing to half marathon pace (or there-abouts) for the last six miles.

I had hoped to hit an average pace of 7:00 to 7:05, but I ended up averaging 7:10. I ran this on a Wednesday following my Sunday 10k, so I’m not sure if I was 100% recovered yet. But I had a 6:30am flight on Thursday for a work conference, and there was no way I was doing this workout before or after my flight. While I was a little disappointed in the pace, I still feel like I’m in a good place going into my race.

Race Results and Time Trials Throughout This Training Plan

I had a lot of tentative plans going into Phase IV, and they didn’t all come to fruition.

Based on when my goal race was, I had 5 Sundays (including the half marathon) in Phase IV. I had hoped to run one or two 5k time trials, a 10k race, and a mile time trial in there.

The 5k time trials didn’t happen. In the first week of Phase IV, I was still feeling really beat up from Phase III. The timing of things also resulted in my last big workout being on a Friday, and I didn’t think I’d be in a good place to have the results I wanted in a Sunday time trial. Then, the week after my 10k race I was traveling for workout. I had tentatively hoped to do a time trial while I was out in San Diego, but between the travel, the weather, and the drinking, that probably wasn’t a good idea either.

I did, however, stick with the 10k and the mile time trial. You can read about my 10k experience in this race report. I finished in 42:03. It wasn’t quite as fast as I had hoped, and this lead me to revise down my expectations for the half just a little bit, but I was still very happy with the results.

The week before my race, I decided to throw in a quick mile time trial. I figured this was short enough that I’d be able to recover and not have any impact on my goal race. And in retrospect, I think that was true.

I initially planned on going to the track to get an accurate measurement, but I didn’t have enough time to that morning to drive out to the track. Instead, I did it around my usual loop at the Orange Reservoir. The path is marked, but I’m not 100% sure of how accurate it is, so I trusted in my GPS watch.

I finished in 5:55, which was more or less my conservative goal. I started off a bit fast and my pace fell off a bit in the second and third quarters. So not a perfect time trial, and probably not a true 100% effort, but still a clear personal best for me. Prior to this training block, my best mile was 6:03.

Setting Goals for My Half Marathon Race

Overall, Phase IV did what it was supposed to.

It gave me a chance to drop my miles and intensity and recover from Phase II and Phase III. It also gave me an opportunity to run a couple races and gauge my fitness prior to my goal race. I wish I’d been able to run a 5k in this period as well, but I’ll have to make do with what I did.

The two race times line up well with each other. The 42 minute 10k and the 5:55 mile are roughly equivalent in the VDOT calculator, and they suggest a 1:33 half is possible.

If I look at the last big workout – 14 miles with 6 at half marathon pace – my pace was 7:10 per mile. That would be roughly a 1:34 half marathon.

Finally, if I look at the threshold workouts throughout the plan, I reliably hit paces between 6:45/mi and 6:55/mi. If I split the difference, a 6:50/mi threshold pace would be appropriate for about a 1:31 half marathon.

With that in mind, I’m going to set my goals for this race as 1:35, 1:33, and 1:31. 1:35 is an easy C-goal, and I’ll be very disappointed if I can’t hit that. 1:33 is probably a tough be realistic goal, and I’ll be very happy to hit that. 1:31 is a stretch – but I think it’s within the realm of possibility. I would be ecstatic if I ran 1:30 to 1:31 in this race.

In terms of pacing, I’ll try and start out conservative (7:10-7:15) for the first two or three miles. From there, if I’m feeling good, I’ll speed up to 7:00 to 7:05 for the middle part of the race. Somewhere between 7-10 miles, I’ll decide whether to speed up a bit more to 6:50-6:55 or to stick it out at 7:00 to the end. If all goes well, that should set me up for a finish time of around 1:32 to 1:33.

Wish me luck. I’ll report back next week on how it went.

1 thought on “My Experience with Phase IV of Jack Daniels 5k-10k Plan”

  1. I think you’re missing the point of the final phase – lactic threshold based sessions are the primary focus and these are key as they are most aligned to race pace. My experience is that thes get you really firing, especially for the 10k and HM. I just ran a 73:30 HM which was a big PB despite being 40 – I attribute more threshold work to that. Jacob Inglebritson swears by it even for the 1500!


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