Intervals: 1 K by 6 Sets @ 4:30/K Pace with 20-Minute Jog Before & After it.

I did intervals tonight. I did it the way it was recommended in a book written by ultra marathon world record holder Mr. Takahiro Sunada. According to him, it is important to keep the interval short. Many runners tend to run at a pace significantly faster than the target race pace, but rest too long, like two minutes. He says that's not good. A better approach is to run at a pace slightly faster than your target race pace, but to keep the interval short, like one minute. I would normally run at a far faster pace than my race pace, but rest for two minutes between reps, which is exactly the way he says I should not do. So I decided to try what he preaches. 

Also, a 20-minute jog was recommended before and after the intervals. In the past, this was an element completely absent in my training. So I decided to do this as well.

I jogged in my new pair of aqua shoes. (See below.)

I changed into my split-toe minimalist shoes MUTEKI (see below) for the intervals.

For the time of each rep, see below:
1st rep: 4:45.28
Rest: 1:00.42
2nd rep: 4:26.52
Rest: 1:00.28
3rd rep: 4:15.37
Rest: 1.00.48
4th rep: 4:24.58
Rest: 1:00.51
5th rep: 4:22.54
Rest: 1.00.28
6th rep: 4:20.56

Although the target pace is far slower than usual, it was fairly challenging because of the shorter interval.

Also, thanks to a short jog before the intervals, my coordination seemed better right from the start. I felt a benefit of jogging for another twenty minutes after the intervals when I finally reached home. I was drenched and felt a far greater feeling of achievement. I really liked Mr. Sunada's approach. I will stick to it for a while. There are many more specific activities recommended in the book that I have never tried. I would like to put them into practice one by one.