Hi, some weeks ago I attempted a sweet-spot workout, I input my FTP (158, done IRL, with max HR from the 20min being 184, averages 166W and 166bpm) and it calculated the watts I should be riding for each interval. I understand that sweet spot is supposed to be sub-threshold or so and is a percentage of FTP.
From running I know my threshold is 184-186bpm (with max 199 when trying to control it in a 5k running race, and just over 200 when really pushing it to the max) and my threshold pace is between 4:30 and 4:48min/km. This is something tested irl multiple times, running on the track around this pace, and when I reach the area of 185bpm and stay there for a little bit, I begin to feel the soreness in my legs. My Garmin watch seems to agree with this (no idea how).
I understand that running and cycling are not the same.
Problem #1: I don’t know my threshold HR in cycling. My max HR from a 20min FTP is the same as my HR from a threshold run.
Problem #2: The scheme of a sweet-spot workout gives me power values (139-143W) that achieve HR Z3 (around 155bpm after 5min) and this is the zone I am rather used to being in and am comfortable in (happens on every group ride and “fun ride”), however it feels nothing like threshold pace/HR in running, hence I believe it’s wrong.
I have done the sweet spot workout along my boyfriend who seems to have the wattage and HR matched perfectly, the HR for sweet-spot calculated in watts lands just below his threshold HR on avg and I can tell his effort is much harder than mine in this interval (he is much more fit than I am with a VO2max 10 points higher than me).
How should I perform the sweet-spot workout? How should I create the HR zones for cycling, are they really different? The FTP result might be slightly skewed because I did not get up at all (idk if I should or not, either way it was done fully seated), but by no more than 0.15W/kg and I have considered recalculating the sweet-spot workout if the FTP was higher by 10 and it made almost no difference.
You are correct that cycling HR is different to running HR. It may be that with a more controlled FTP test (indoors, on the trainer) you might get a different result (including a higher HRmax reading).
A sweetspot workout should be noticeably easier than a threshold workout, say 7/10 RPE.
At your calculated 90% of FTP (143/158), you are working in sweetspot and just below the lower end of threshold.
Generally, sweetspot HR would be around 80 - 85% of HRmax cycling. So your 155/184 = 84% is pretty much where it is at.
It is not uncommon for there to be some mismatch between HR and power zones (especially near the “boundaries”). This is no bad thing at all.
Here are a couple of options to consider
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Up the power from 90 to 92 / 93 / 94% of FTP (still sweetspot) if you want to go harder, but be careful not to end up inadvertently doing a threshold workout if your intention is to do a sweetspot workout.
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Extend the duration of the work intervals and see how long (and indeed if) your HR nudges up later in the intervals. 20, 30 and 60 minute sweetspot intervals are commonly used. Sweetspot progression is primarily through extending the time in zone.
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One more thing that came to me is that the FTP test is a functional power THRESHOLD and achieving a max HR of 184bpm at it would match the threshold in running (+/-), which would hint that the set of HR zones is the same, or almost the same.
I compared the FTP test result to races or group rides or workouts and it seems adequate. I later did a 5min test and planned to extrapolate the 20min FTP from it but I had the ant+ disconnect for a bit and I didn’t fix it.
One other thing to consider is cadence, especially if you are doing workouts on a trainer in ERG mode.
Generally, if you reduce your cadence a little and keep the power constant, your HR will also reduce a little.
Same in reverse. Constant power, up the cadence a little, HR will increase a little.
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Thanks, I do take cadence into consideration, certainly higher cad → higher HR.
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