"But all this really didn’t hit me until half way through our short 40-minute trail run—my heart rate was about 10 beats lower than usual. This was evident because I felt myself going faster—much faster.
"I thought Phil [Maffetone] was behind me all that time to analyze my gait, but now it was evident that, not only did I make up the difference of 10 beats between Phil’s heart rate and mine, it was lower by a couple more beats. I need to get him a pair of these (well, even if it made him run faster).
"All these new albeit relatively minimal but noticeable changes in my gait translated to almost a minute a mile faster at the same heart rate! We also run by time, not sure of the exact distance, and don’t have mile splits so this was not a scientific study.
"But today we ran again—same course, same time of day, same result. I love running fast! The human body never ceases to amaze me."
My friend David called me shortly after getting his first Vibrams and running in them on a treadmill. He wanted to know if it was normal that his heart rate should be 10 points lower than it usually is. I told him that it was.
P.S. A paper was just released confirming this effect.