I’ve spent a significant amount of time doing this workout on the trainer over the past 6-8 weeks and need some advice. Also, let me reference this with the fact that I’m fairly new to training with power.
I’m using Trainer Road with a Wahoo Kickr as well as a Garmin Edge 500. I’ve had no issues with any of the devices but have noticed an odd pattern and am curious. All devices are set to the same FTP/LTHR settings.
If I’m doing the workout at 85% FTP my HR usually averages in the 148-155 range for the first interval. I’m noticing that my HR is dropping fairly significantly during the second 20 minute interval and I’m not sure why?
As an example, I did the workout today and my average power, HR and cadence for the first set was 204/148/95. After a 5 minute recovery I tackled the second set at a higher wattage and my numbers were 223/125/94. This being said, my average wattage increased and my heart rate decreased. I’m pedaling at the same cadence with a harder wattage and would assume my heart would work harder and therefore have a higher heart rate?
Help me? What am I missing here? I’ve noticed this on several of my workouts as of late and can’t figure it out. I’ve even gone as far as purchasing a new HR monitor as I thought mine might be bad.
Any help, suggestions, comments or thoughts would be greatly appreciated!
are you sure you are getting a good contact with your HR monitor? It needs to be tight across the chest to keep the contact when crunched up in a bike riding position.
85% is on the easier side of what you want to be doing 2x20 at.
My warm up is in the 8-10 minute range with a few intervals ranging from 65-100% FTP.
I vary the workouts from 85% to 105% FTP depending on if I run afterward or not and no matter how I do them my HR average is lower in the second interval.
On my fluid trainer, I would see the same results. Higher wattage and lower heartrate on the second interval, but I attributed this to the fluid trainer getting easier as it heated up.
On my Kickr, I have a slightly higher heartrate on the second interval with same wattage across both.
Any help, suggestions, comments or thoughts would be greatly appreciated!
Sounds like your trainer’s resistance is not consistent. You are getting same wheel speed for less real power after it heats up, but the virtual power readings are using wheel speed. Try a real power meter, or a trainer that’s less susceptible to such drift.
Any help, suggestions, comments or thoughts would be greatly appreciated!
Sounds like your trainer’s resistance is not consistent. You are getting same wheel speed for less real power after it heats up, but the virtual power readings are using wheel speed. Try a real power meter, or a trainer that’s less susceptible to such drift.
When you say “real” power meter I assume you mean hub or crank based?
Is the KICKR power measurement not “real” or are their know instances of it having significant drift? I’m confused.
Also, I’m not under the impression that it’s a power issue. The resistance on the crank becomes harder or stays the same depending on the workout. My heart rate dropping is my concern.
It sure sounds like either your Kicker is reducing its resistance on the second interval or your HRM is not functioning properly. Even if I’m well hydrated my pulse will be up at least a couple of beats at the end of my second 20 minute interval when done at the same power as the first working in ERG mode. Twenty beats lower on the second says you’re putting out a good bit less power or the HRM is on the fritz. How hard does the 2nd 20 minute session feel compared to the first? If it actually feels easier then your Kicker is acting up.
It sure sounds like either your Kicker is reducing its resistance on the second interval or your HRM is not functioning properly. Even if I’m well hydrated my pulse will be up at least a couple of beats at the end of my second 20 minute interval when done at the same power as the first working in ERG mode. Twenty beats lower on the second says you’re putting out a good bit less power or the HRM is on the fritz. How hard does the 2nd 20 minute session feel compared to the first? If it actually feels easier then your Kicker is acting up.
I will second this & what most others have been saying.
Also, this might be a stretch, but have you had your heart checked out? Maybe you shouldn’t jump to rule out some sort of heart condition (I mean, most likely not, and hopefully not, but it’s best to be on the safe side with these things). Did you feel weird during the second rep? Chest pain? Light-headed? If something feels funny you should see a doc.
Quite frankly I normally feel much more relaxed on the second interval than the first. That’s not to say the effort is easier but that I’m more in my “grove” so to speak.
I’ve tried three different heart rate monitors and had the same results with each one.
I’ve also calibrated both the KICKR and Trainer Road on a fairly consistent basis.
Also, I don’t experience this HR issue with a VO2Max workout. It only seems to happen in the second interval of a 2 x 20’ session.
I can’t speak with 100% confidence regarding your Kickr, but I train with a Quarq and record data on a Garmin Edge 800 and also record the power from the Wahoo on Trainer Road. I have compared the power from the two for numerous workouts and have not seen drift or inaccuracies more than 3% between the two.
I’d be interested in seeing the TR graph from those if you can post that.
8-10 minutes isn’t really a sufficient warm up. I think you’re still cold and thats why both PE and HR are elevated for the first interval.
There is a great video by TeamSky on their warmup… it’s basically a ~5min easy spin then a ramp from easy spin to FT over 5-10min and then a couple 10-15 second sprints. I use it for basically every hard bike workout I do it’s funny how I can feel awful during the ramp, but I’m ready to kick ass after the sprints.
i train with a Quarq and garmin 705 on a turbo trainer. I have a 15 min warm up routine before the 2 x 20’s, I always have 5 mins in between not 2 mins as I find it easier on the brain! I calibrate the Quarq before every session and the numbers are consistently between 184 and 192 - so I am pretty sure the Quarq is good to go. I use a Garmin HRM strap that came with the 705. I have not used the HRM for over 2 years as I could not see the point when training with power, but recently have gone back to using it to inform what happens in L5 or L6 intervals but generally out of curiosity.
I too have seen his effect. I am pretty sure my equipment is not the source of the unexpected result. I have no reason to suspect my power meter is reading differently between the two intervals, I know the turbo is warmed up after 15 mins from past experience and besides if it started rolling easier my power numbers would go down - which they don’t.
I have observed this for a few months now - I am not getting differences of 15 to 20 BPM, only maybe 5 BPM difference between the two intervals but it is consistently there. It has also been bugging me to the point I was going to start and put a 2 min rest period inbetwen the two intervals instead of my favored 5 mins and see what happened. My only explanation is that I set off doing the first 20 min interval and my HRM has to suddenly bump up to meet the increased demand. It never really recovers from this so always maintains an ‘offset’ if you understand my meaning? The second interval starts off and because there is no sudden increase - I have already been working at that level for a short time - the HR settles into a slower pace.
Not a very scientific conclusion but I have no other explanation. I will be changing my warm up to put in a 2 min L5 interval which should stress the HR beyond L4 (FTP) before the first interval starts. If that settles the HR down it is something to consider before starting a TT during your warm up I would think.
8-10 minutes isn’t really a sufficient warm up. I think you’re still cold and thats why both PE and HR are elevated for the first interval.
Eight to ten minutes is probably a bit short for someone doing VO2 max or harder efforts but riding at an IF of .85 or so it should be just fine if done as a nicely progressive build from say 100 watts to begin with and then ramped up to your goal effort over the course of the warm up. Heck I’m doing 3 X 20 of .9** IF** every day with more like 5 or 6 minutes of progressive warmup and I’m in my 60s. Being a bit cool in the beginning suppresses my HR rather than increases it.
Toadbra,
When are you turning fans on? After the first 20 minute session by any chance? It’s a nice mystery. Something is certainly at play here.
warm up and do the spin down test, then do the first 20 in erg mode, then switch to trainer mode and use your gears to keep the power in the same zone and see what results you get
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