I started studying workout statistics after I bought my Garmin Fenix 3HR back in April of 2016. At the time, I wasn’t sure how much I would be involved in OCRs, training and tracking stats. But the stats that the Garmin tracks on my performance are pretty incredible and addicting to follow with the watch alone. I started to notice that as our workout intensity increased, my heart rate seemed to be less accurate for some reason. I read some blogs and confirmed my suspicion – the fast paced movements of the HIIT workouts were causing me to sweat a lot more which then caused my watch to move all around my wrist. So between the sweat interfering with the optical sensor and the movement of the watch along my wrist, my heart rate readings became skewed and unreliable. I soon found the Garmin HRM to be the optimal solution to not only solve this problem but also give me more stats to track. It’s crazy what this little sensor can do.
Running Stats before HRM:
Running Stats after HRM:
Notice “Vertical Ratio” and “Ground Contact Time Balance” (seen in screenshot above) have drop down options to change those stats to “Vertical Oscillation” and “Ground Contact Time” respectively (seen in screenshot below).
As you can see in the screenshots above, the HRM-Run provides 5 additional running dynamics metrics:
Stride length — length of your stride from 1 footfall to the next; measured in meters
Vertical oscillation — degree of ‘bounce’ in your running motion; displays the vertical motion of your torso, measured in centimeters for each step
Vertical ratio — ratio of vertical oscillation to stride length (displays a percentage); a lower number typically indicates better running form
Ground contact time — amount of time in each step that you spend on the ground while running; measured in milliseconds
Ground contact time balance — displays the left/right balance of your ground contact time while running (displays a percentage); for example, 53.2 with an arrow pointing left or right
How I use this additional data
Aside from the overall benefit of tracking a more accurate heart rate during my intense workouts, there are a few benefits of this additional data I want to point out.
The Ground Contact Time Balance I found particularly interesting (and shockingly accurate) as I got injured. I slowly built up and injury in my left leg pain that was obvious to see when reviewing this data point. I noticed I was spending 1-2% more time on my right leg – I favored that leg as my left leg was hurting. Now in this case and example, I knew I had injured my leg before I saw the data point. However, if I didn’t know, this would have been a key indicator for letting me know something was wrong with my left leg. So to touch on accuracy for a minute, when I got the HRM I already had this injury. But I wanted to test out the HRM. I went for a short 2 min jog up the street in my neighborhood. I started to notice some slight pain in my left leg about 1:15 in and I specifically looked at my watch to get the time when I felt the pain. When I got home I looked and sure enough at the 1:15 mark, you immediately see my running dynamic for Ground Contact Time Balance start to favor my right leg. Before the 1:15 mark the statistic was fairly balanced at roughly 50% for each. Crazy how accurate and quickly it picked this up.