[Warrior-Mentor]

LT - No worries.

Couple thoughts for your consideration:

Pace: I used a 1/4 mile track to help accurately track my pace and to get used to it.

12.5 minutes/mile = 4.8 miles/hour

Call it 4.75 mph (for easy math) = 19 laps/hour (on a 1/4 mile track)

Pace in:
Min/Mile | Miles/Hour | Laps/hour | Min/Lap | Laps/Min
12.0 | 5.0 | 20.0 | 3.00 | 0.33
12.5 | 4.8 | 19.2 | 3.13 | 0.32
13.0 | 4.6 | 18.5 | 3.25 | 0.31
13.5 | 4.4 | 17.8 | 3.38 | 0.30
14.0 | 4.3 | 17.1 | 3.50 | 0.29
14.5 | 4.1 | 16.6 | 3.63 | 0.28
15.0 | 4.0 | 16.0 | 3.75 | 0.27

In other words, to do cover 1 mile in 12.5 minutes, you've got to get used to walking 1/4 mile lap every 3 minutes. Broken down further, you could say you've got to cover a 1/3 of the track every 60 seconds.

You've got the benefit of a GPS to track your speed, so you might not want/need to use a track. I recommend it at least once [even wth a GPS] so you can get the "visual" feel of the pace as well.

The next logical question [which you asked] is, "How do I speed up to get to that pace, WITHOUT running?"

Stride: Consciously work to lengthen your stride. At 5'10", I worked to get my comfortable, fast ruck stride to match that of guys who were 6 inches taller than I was. It feels a little ackward at first, but you can get used to it.

Arms: This pays the biggest, and fastest dividends in terms of immediate return on effort. Concentrate on swinging your arms very quickly and at a full swing. For whatever reason, your legs respond to the speed of your arms. It's strange, but it works. Without a weapon, swing your arms straight forward and back. With a weapon, I swung the weapon rapidy from side to side [or carried it in one hand, swinging it forward and back].

Good luck.