The Ambiguous Tempo Run

Each of the training plans I've followed have defined "tempo run" differently.

In the Solving the 5K Puzzle article from Runner's World, Pete Magill defines a tempo run as:

Tempo runs are one of the great misunderstood workouts of our sport. In his seminal book, Daniels' Running Formula, ubercoach Jack Daniels writes that "the intensity of effort associated with [tempo] running is comfortably hard. [Y]our effort should be one that you could maintain for about an hour in a race."

The 10K training plan I've been following from Women's Running defines a tempo run simply as 10 seconds per mile slower than race pace.

The Hal Higdon half marathon training plan has this definition:
This is a continuous run with a buildup in the middle to near 10-K race pace. A Tempo Run of 30 to 45 minutes would begin with 10-15 minutes easy running, build to 15-20 minutes near the middle, then 5-10 minutes easy toward the end. The pace buildup should be gradual, not sudden, with peak speed coming about two-thirds into the workout. Hold that peak only for a minute or two. A Tempo Run can be as hard or easy as you want to make it, and it has nothing to do with how long (in time) you run or how far.

Runner's World has a whole article devoted to defining the tempo run and admits that different people use the term differently. The article summarizes it as an effort that should be "comfortably hard—one that could be maintained for an hour in a race," which is the same as the first definition.

To be fair, the 10K training plan gives such a specific definition because the plan is based on hitting a specific time goal. Since this is the plan I've been following, my "tempo runs," which are just 10 seconds slower than race pace, which in reality is my 5K and not 10K race pace, is extremely difficult. No wonder I've been struggling to hold that pace for 3-3.5 miles.

Today was my last of these tempo runs before my 10K race on Sunday. It was just 2 miles at tempo pace sandwiched in between easy paces. I've been getting better at being consistent with my tempo pace, but the 2 miles was still tough (tougher than "comfortably hard") but doable. Today I practiced being present and visually finding anchors to pull me forward instead of continually checking my watch. This strategy works well for me and will definitely be useful on race day.

I'm leaning toward trying the Hal Higdon half marathon plan, but I'm still unsure of how to run a tempo run on that plan. He says peak speed should only be held for a minute or two. That is much different than the other definitions that you should be able to hold it for an hour. Should I stick to the Hidgon definition if I'm following that plan?

Do you follow the tempo run definitions in the training plan you're doing, or do stick to a certain way of doing tempo runs? Is there a best way to do a tempo run?