I used the Garmin Forerunner 630 with the HRM-Run heart rate strap during cardiac rehab yesterday. If you look at the image above you’ll see there are some anomaly’s with how the 630 records the data on a treadmill. I started out at a 6 mph (10:00/mi) pace. Then I alternated walking with increased pace running.
This is the more detailed pace data chart from above. You can see that even though I had the treadmill set at 6 mph, the Forerunner 630 didn’t quite have me at the 10:00/mi pace. I then walked to lower my heart rate before increasing the speed to 6.5 mph which is about a 9:13 pace. I started that block of running at 6.5 mph and increased .1 mph every minute up to a 7 mph pace (8:34/mi). But as you can see from the above chart, it shows I barely broke the 6 mph (10:00/mi) pace, and only very briefly. I walked again and then ran for 3 minutes at a 7 mph (8:34/mi) pace. I did that again except I ran for 3 minutes at a 7.5 mph (8:00/mi) pace. The Forerunner doesn’t really show any of the speed increases with any accuracy.
For this chart I want to talk about the “stops” the Forerunner 630 is recording. You can see around the 15 and 21 minute marks, the 630 shows me stopped. Yet, based on this chart it’s still recording both run cadence and vertical oscillation data. I walked, but never stopped. What’s interesting to me is that the first drop in pace data occurred right before a major speed increase and the second occurred right after a major speed decrease. I did the same thing two more times during the run and it never dropped the pace data again.
For now, I’m gong to rate the treadmill data from the Garmin Forerunner 630 as inaccurate. I will be running on the treadmill more in the near future and I’ll see if anything changes.