HR vs. Power vs. Pace vs. GAP - an experiment | 80/20 Endurance

HR vs. Power vs. Pace vs. GAP – an experiment

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  • #10774
    winoria
    Moderator

    Hello 80/20 forum!

    I have to commit that I’m pretty much a numbers geek and I truly enjoy comparing date and doing experiments. For a long time, I was wondering about running power. While using a power meter on my bike for a while, I never really considered buying one for running. I knew it existed but I probably ignored it 🙂
    Anyways, I was reading about it and also in the 80/20 triathlon book it is mentioned as the best metric for running (followed by pace and heart rate – in that order).
    Stryd (I’m not trying to make this a commercial) offers a 30 day testing period or better return period and I decided to give it a shot. I received the Stryd pod yesterday and had a RSI1 coming up today which, at least to me, seemed to be a good workout for a first trial (David & Matt: don’t be surprised b/c of the RSI1 on a Thursday, I had to shift workouts around as my pool will be closed for COVID cleaning the next 4 days so I had to change the schedule for this week).
    For those of you not knowing what RSI1 is:
    5min Z1
    5min Z2
    6x1min Z5 / 2min Z1
    5min Z1
    total: 33min

    Before I share the numbers – I will compare HR vs. Pace vs. GAP vs. Power, I want to make you aware that this is not a scientific test nor am I a professional tester or athlete (LMAO) but rather a amateur who likes endurance sports and enjoys the forum as well as numbers.

    Here now the numbers:
    Lap 1 (5min Z1):
    Pace: 9:33min/mile
    GAP: 9:08min/mile
    HR: 127 BPM
    Power: 216 W (NP 220W)

    Lap 2 (5min Z2):
    Pace: 8:17min/mile
    GAP: 8:28min/mile
    HR: 137 BPM
    Power: 225 W (NP 225W)

    Lap 3/5/7/9/11/13 (Z5)
    Pace (Z5): 5:41 – 5:31 – 6:01 – 5:36 – 5:25 – 5:52 min/mile
    GAP (Z5): 5:26 – 5:30 – 5:50 – 5:59 – 5:39 – 5-51 min/mile
    HR (Z5): 164 – 163 – 165 – 163 – 164 – 166 BPM
    Power: 336 – 323 – 329 – 298 – 308 – 316 Watts
    NP: 341 – 330 – 321 – 304 – 314 – 322 Watts

    Lap 4/6/5/10/12/14 (Z1ish)
    Pace (Z5): 8:50 – 8:42 – 9:24 – 8:22 – 8:35 – 8:28 min/mile
    GAP (Z5): 8:32 – 8:47 – 8:46 – 8:34 – 8:33 – 8:40 min/mile
    HR (Z5): 150 – 150 – 156 – 153 – 157 – 156 BPM
    Power: 236 – 229 – 239 – 230 – 236 – 225 Watts
    NP: 230 – 221 – 233 – 226 – 232 – 222 Watts

    Lap 15 (5min Z1):
    Pace: 9:10min/mile
    GAP: 9:01min/mile
    HR: 136 BPM
    Power: 218 W (NP 219W)

    What are my thoughts? Well, I find the power numbers quite interesting. I also think, that a watch that would show live GAP could be an alternative. I’m quite certain that HR is not really good for intervals – not a surprise though.

    If from interest, I can share more data as I will keep the pod for the 30 days and decide then how to proceed. I will keep running by pace and will keep collecting power date, etc.

    winoria

    #10779
    Matt Fitzgerald
    Moderator

    Thanks for the information, Winoria. By all means, keep it coming. I have a couple of one-on-one coaching clients who train with Stryd and I generally find it super reliable. Not reliable enough that I would ever allow it to completely control my decision-making, but a very useful supplement to other data (including subjective data).

    #10800
    MartinH
    Participant

    I’ve recently switched to power, and am finding it easier to use than the HR I was following previously – which mostly means my watch doesn’t beep at me to slow down as much as it did when I was working with HR 🙂

    #10882
    winoria
    Moderator

    Here a brief update after an RF12 run:

    Lap 1:
    Pace: 9:14min/mile
    GAP: 8:51min/mile
    HR: 131 BPM
    Power: 215 W

    Lap \2:
    Pace: 8:35min/mile
    GAP: 8:33min/mile
    HR: 144 BPM
    Power: 225 W

    Lap 3:
    Pace: 9:17min/mile
    GAP: 9:32min/mile
    HR: 135 BPM
    Power: 195 W

    David/Matt: have you ever tried or had an athlete that actually ran by GAP/NGP?

    #10885
    Matt Fitzgerald
    Moderator

    I have not. When power came along it sort of obviated those metrics.

    #10903
    winoria
    Moderator

    Some more data from an RAn4 that was ran as a brick (CF9 before the run):

    Lap 1:
    Pace: 8:52min/mile
    GAP: 8:27min/mile
    HR: 128 BPM
    Power: 225 W

    Lap 2/4/6/8/ (Z4)
    Pace (Z4): 6:25 – 6:18 – 6:16 – 6:07 min/mile
    GAP (Z4): 6:25 – 6:18 – 6:15 – 6:20 min/mile
    HR (Z4): 155 – 158 – 163 – 163 BPM
    Power: 307 – 307 – 311 – 304 Watts

    Lap 3/5/7/9 (Z1 ish)
    Pace (Z4): 8:33 – 8:35 – 8:47 – 8:38 min/mile
    GAP (Z4): 8:25 – 8:26 – 8:37 – 8:52 min/mile
    HR (Z4): 136 – 140 – 140 – 137 BPM
    Power: 230 – 226 – 222 – 214 Watts

    I start to really like running by power but will keep collecting data before I make a decision to switch (the plan) from pace to power.

    #10912
    jnatiw
    Participant

    This is fascinating. I have a long (35 year) relationship with pace, a more recent relationship with HR (thanks to the 80/20 book). As a result of being old and set in my ways, I have a healthy distrust of a foot based power meter (I do have power pedals on my bike, so I’m not completely out of touch). This is a great read. Thanks for posting and for the replies.

    #10961
    winoria
    Moderator

    RT19 today and I decided to give it a shot to also be able to establish a real running FTP.

    5min Z1
    Pace: 9:50 min/mile
    HR: 117 BPM
    Power: 206 W (209 NP)

    10min Z2 (including 3 x 30 sec bursts)
    Pace: 8:20 min/mile
    HR: 134 BPM
    Power: 229 W (234 NP)

    20min TT
    Pace: 6:37 min/mile –> Threshold pace: 6:58/mile
    HR: 170 BPM –> Threshold HR: 162 BPM
    Power: 293 W (293 NP) –> Threshold Power: 278 Watts

    50min Z2
    Pace: 8:43 min/mile
    HR: 143 BPM
    Power: 227 W (228 NP)

    5min Z1
    Pace: 9:14 min/mile
    HR: 129 BPM
    Power: 206 W (206 NP)

    What I find interesting is, that the FTP would give me a Zone 4 of 286-334W and Zone 5 of 334-2000W. Looking at the above mentioned RSI1, I doubt that I could hit the Zone 5 numbers:
    Lap 3/5/7/9/11/13 (Z5)
    Pace (Z5): 5:41 – 5:31 – 6:01 – 5:36 – 5:25 – 5:52 min/mile
    GAP (Z5): 5:26 – 5:30 – 5:50 – 5:59 – 5:39 – 5-51 min/mile
    HR (Z5): 164 – 163 – 165 – 163 – 164 – 166 BPM
    Power: 336 – 323 – 329 – 298 – 308 – 316 Watts
    NP: 341 – 330 – 321 – 304 – 314 – 322 Watts

    I have a similar issue when swimming but I think that is b/c of my sloppy technique when trying to swim fast.
    While it feels easy to maintain a medium-high/decent power/or pace (swimming) for long time (relatively speaking), I have a hard(er) time hitting the Zone 5 targets.
    I’m not worried to hit Zone 5 numbers based on running pace however (6:03 – 0:02)
    I feel like it is not a big issue for long distance athletes but I wonder why? Slow-Twitch vs. Fast-Twitch?

    Matt or David, what do you think is the root cause for that? Should I even bother?

    #10966
    Matt Fitzgerald
    Moderator

    You have a gift for finding the cracks in our zone system! The issue is that our pace-based, HR-based, and power-based zones don’t truly align. It’s almost impossible to get them to do so at the population level. The best way to get them to align for YOU individually is to do so manually. By this I mean: Choose one intensity metric as your anchor. Let’s say it’s pace. To get power to align with your established pace zones, go out in the field and find what wattage you are actually producing when you are running at threshold pace, at the bottom and top ends of Z4 pace, etc. If you do this you will eliminate all discrepancies between the two metrics.

    #10969
    winoria
    Moderator

    Thanks for the swift response!
    I was always hoping to be gifted but I would have picked something different I guess 🙂
    I will likely make a plan switch to power as I really start to like it – especially in windy and hilly conditions.

    #11008
    winoria
    Moderator

    Another – most likely likely last – update, as I don’t want to bore people with this. I thought however, that by adding one run that was performed based on power target not pace target would be interesting for people who consider making the switch to a running PM. Today, I ran the very first time based on power targets, condition were rather difficult, 32F and 20-30mph winds brrrrr – RCI9:

    5min WU Zone 1:
    Power: 209W (NP 212W)
    HR: 114 BPM
    Pace: 9:46min/mile (GAP 9:20min/mile)

    10min WU Zone 2:
    Power: 231W (NP 231W)
    HR: 132 BPM
    Pace: 8:16min/mile (GAP 8:15min/mile)

    4x7min Zone 4:
    Power: 269W (NP 269W) – 270W (NP 270W) – 276W (NP 277W) – 272W (NP 273W)
    HR: 153 BPM 157 BPM 162 BPM 162 BPM
    Pace: 7:06(GAP 6:57) 6:47(GAP 6:52) 7:01(GAP 6:52) 7:02(GAP 6:54)

    4x3min Zone 1:
    Power: 218W (NP 216W) – 230W (NP 229W) – 222W (NP 221W) – 210W (NP 209W)
    HR: 139 BPM 147 BPM 148 BPM 142 BPM
    Pace: 9:04(GAP 9:01) 9:41(GAP 8:47) 8:53(GAP 8:37) 8:30(GAP 8:54)

    15min CD Zone 2:
    Power: 234W (NP 235W)
    HR: 143 BPM
    Pace: 8:19min/mile (GAP 8:08min/mile)

    5min CD Zone 1:
    Power: 207W (NP 208W)
    HR: 132 BPM
    Pace: 9:23min/mile (GAP 9:13min/mile)

    I really think that running based on power prevents one from going too hard uphill. That’s probably the greatest benefit. I’m not going much faster downhill just to stay in my power zone as I don’t want to ruin my joints, but I feel much stronger when running on the flats as I saved quite some energy that I would normally “waste” on the hills. I like the fact to not display my pace on my watch but only run by power and time.

    winoria

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