Hello i read that article too. The idea is to run 1st mile 6% faster than anticipated average pace. Don't know if thats good or not.
But in the article there were a few other tips, i've implemented in my training. Always used to slow down in the 3rd and 4th km
So at the end of a long run i have started throwing in a km split at my 5km race pace, the idea is to simulate that 4th km (or in my case 3rd and 4th km when i slowed down)
Last months 5km i did start out fast, not 6%, but it was fast, but i didn't slow down as much (only about 20 seconds) as i normally did.
Only other thing i've done different was the introduction of 1km intervals.
Don't know what training you are doing, has there been any changes to your routine etc.