I’m seeing weird results with my heart rate strap. My ground contact time is really low, but my vertical oscillation is really high! One indicates good form, the other indicates bad form. My subjective experience is that my vertical oscillation is low, but my garmin disagrees.
And I think the reason why is the movement of my breasts. I think they’re moving the sensor itself, and confusing its measurements.
Is that actually a thing? I’ve tried to find research or people talking about it, but all I can find is discussion on the impact of breasts on actual running performance, rather than on the measurement of it.
The strap normally goes just below the chest rather than on, so if the issue is due to movement, then that should minimise it.
Water or saliva can also aid electrical contact of the strap with your skin, if you’re not already doing that.
The strap sits in the right place, just below the breast crease. The issue is that the strap itself can’t be moved far enough away from that area to avoid breast movement
On really long races with a backpack, my HRM strap has often got nudged down so it’s practically round my abdomen, and it still worked fine. Why don’t you give it a go much lower and see what happens? That might help settle the breast question?
So, it didn’t really seem to make a great deal of difference, but I’m not sure if I was able to get the band low enough. I had it right at the bottom of my sternum, but couldn’t go lower without it being weird and uncomfortable. And when it was still on my sternum, it was still partly under my bra, so there was likely still movement impacting it…
I’m sure I saw a video recently that talked about women-specific HRMs which attach onto the bottom of a sports bra rather than being on a strap. But I couldn’t find it again just now when I searched and I didn’t pay super close attention the first time, because I (a cis man) am not the target demographic. So I dunno if this specifically is what they’re supposed to solve, but it seems reasonable to think it might be.
Here’s a YouTube video for a women’s-specific HRM from the manufacturer.
I don’t think it’s the answer as such, but I think the answer is on the page for that product, which is to say my existing bras probably aren’t supportive enough. That product only works with high support bras, which mine aren’t…
Can’t hurt to try I guess! I’ll give it a go
You could also try tightening the band a small amount to see if that reduces the oscillation measurement. You could also take a video of yourself running to confirm or deny what the strap is saying about your form.