This morning's run brought me closer to understanding the impact of the metronome, but there is still a missing piece of the puzzle. I put a new battery in my foot pod and clipped it to my shoe for the first time since I bought my Garmin FR210 in May 2011. The FR210 uses GPS, but the foot pod allows me to capture my cadence during my run. It's a metric I've missed having when I analyze my performance data.
The good news is that I now have proof that the metronome works. I set the app for 87 SPM before I started and the data shows I averaged exactly that on today's run. This is no coincidence. I have mounds of pre-FR210 data that shows that (at best) I used to average 83 SPM on a training run. The cause and effect of the metronome's beat could not be clearer. All I have to do is jump it up to 90 SPM and my performance is optimized. Problem solved!
(Cue sound of record scratch)
What? That's not the whole story?!! Indeed it is not. While there seems to be evidence supporting the effectiveness of a metronome, the result of today's 87 SPM performance was an average pace of 9:42 per mile. I measured my route using two different browsers (Milemeter is behaving much better now) and they were pretty consistent, so I'm going with that pace. So cadence improves, and my pace gets worse. Huh?
The last puzzle piece clearly involves stride length. It's likely that I'm achieving my SPM target by maintaining a shorter stride. It makes sense that opening stride length with an increasingly higher cadence will bring my pace down to my targeted level. Sounds easy, but we all know the danger of over striding. I think I'll take one victory at a time and work my way up to 90/180 SPM and see what that gets me. Once I can do that consistently (and without the need for a metronome), I can start experimenting with stride technique.