Getting a bit more serious now. Threshold run with BSX Insight

OK. I’ve faffed about too much so far this year. Hackney and Hever beckon with the Hackney Half being the more pertinent of the two.

Today’s session for me was 25 minutes of grimacing (that’s a technical running term btw). Basically 90 seconds at 5k pace and then 90 seconds at HM pace. Easy huh? If you have no rest and repeat for 25 minutes it gets harder though 🙂

But still not too hard as it’s clearly easier than your 5k race effort if you think about it. Although in some ways varying the effort with no rest adds a new level/kind of discomfort. I would actually prefer to do a flat out 5k and get the pain over and done with much more quickly. But that wasn’t the session.

As your HM pace is probably below your threshold pace then this session will have you tottering under and over your threshold level. You test/push that threshold level in your body. In theory your body adapts to that and, over time through training, raises your threshold higher. Which is a good thing.

I played with the BSXInsight again. I’m still waiting for Garmin to sort a few things out with FIT files then I’ll spend more time on it.

I don’t want to go into this too much but here are the SmO2 and HR plots


I did a bit of stretching and the like before turning the device on so I’d ‘warmed up’ (75/76%). I then jogged slowly for 21 minutes or so. Yet you will see that after 21 minutes I stopped for about 30 seconds before starting the meat of the run. You will notice here that my levels of oxygen are higher (77.4%). ie there is more oxygen after I  REALLY warmed up with a 20 minute jog. 

OK so I’m clearly NOT saying that a 20 minute jog is the perfect warmup. But I am saying that faffing about a bit and then going for your 5k PB is most definitely NOT optimal. There WILL be an optimum level of warmup where you can start your race in the best possible oxygenated state. Tools like BSX may well help YOU find the right level of ‘warmup’ for you.

You will also see that as the run proceeds the oxygen state progressively gets worse until around 30 minutes or so where it flattens out. This was NOT a race level effort for 25 minute duration but I think what you can take away is that it shows that you arrive at a point where you can supply a certain amount of oxygen and also consume a similar amount. Maybe the graph shows that level for me is 69%, maybe that is the sort of level I can sustain for 10k or 10 miles. Maybe.

But what we might find the likes of BSX/Moxy can do is also tell us what one of our physiological limiters is. So is the limiter in the oxygen supply or oxygen consumption at that 69% level? For me, above, I would suspect that the problem is with my ability to use the oxygen as many people can operate at levels well below 69%. Anyway I don’t think I can draw that conclusion yet. I’m just giving you a flavour of what you might discover about your body and how it works and THEN what training might be most effective.

Going back to Run Hackney. Wouldn’t it be nice to know for a HM what level of oxygenation you can work at for the FLAT HM race? A real TT/track-type effort. Sure you might also know what level of HR you can sustain, which could be similar but what if you only have caffeine tabs before races and not before training….that’ll skew your data for one thing. Sure you might also know your sustainable pace or you could run by feel.

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2 thoughts on “Getting a bit more serious now. Threshold run with BSX Insight

  1. What was going on with your run starting at the little orange marker on your HR chart? Looks like you threw in some surges or long strides.

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