Personally, I don't see the value in power for running for most people. In its current form, they aren't actually power meters, but more of power estimators. Stryd doesn't measure direct force - It uses a barometer and an accelerometer and a bunch of formulas to estimate power -- sort of similar to the PowerPod. Even if it is within 5% accuracy, 5% from a 6 minute mile could be anywhere from a 5:42-6:18. That's a huge variance.

With cycling, you're pretty much doing the same movement over and over. Your cycling form doesn't change much over the course of a ride as your feet are clipped into your pedals and moving in a circular motion. A direct increase in power across the board will increase your speed.

With running, everyone's form is different. Foot strikes are different, gait is different. Heck, the difference in your form at mile 1 is significantly different than mile 20. For distance running, you're actually trying to minimize your power output over the course of the race. When you actually get tired and your form gets worse, you actually are using *more* power than for the same pace earlier in the race.

Weather can also play a larger effect on your overall run. If it's 90 deg out, your core temp is going to rise, you're going to sweat more and become dehydrated. You might be running the same pace and wattage as a cooler day, but your HR is going to be up and you're eventually going to slow. With cycling, you get the advantage of the wind produced by moving faster, plus you have water with you at all times. So while performance might decrease as well on the bike, it's not nearly as drastic as while running.

Will running power meters eventually catch on? Possibly. The running world has been focused on pace and hitting specific times for track intervals though and runners at all levels have been extremely successful. Since running itself is more based on times than place, and most races are consistent efforts than cruise, attack, cruise, sprint, cruise, sprint of many bike races I've seen, I'm just not sure how that power number really fits in to either racing or training. If your goal is to qualify for the Boston Marathon with a 3:05, then you better be able to run that 7 minute pace the entire race. Running with 280w isn't going to get you in.

[MENTION=193221]musicmaster[/MENTION] - To your original question, yes, a power meter is definitely worth it. As you noted, it'll help you maintain your pace at a level that will let you arrive at the run start with enough energy to make it through the run at the pace you want to hold. Finding that pace will take some time and experimentation, but you've probably figured that out. As noted above, you'll have to figure out your functional threshold power (FTP) and base your training zones off that. Training and Racing with a Power Meter, mentioned above, is an excellent resource for that.

As for heart rate differences between cycling and running - IME, cycling HR is almost always lower than running HR at a given RPE. I think it's due to the fact that your whole body is working at every stride to support your body weight and move you forward when you're running, while your weight is supported while cycling.

I was wondering about your cadence too. Experienced cyclists tend to ride at ~85-95 rpm on level ground. Tri folks I've ridden with seem to ride at a much lower cadence, which puts a disproportionate amount of the load on your legs and lets your cardiovascular system off easy. This might be the problem you're having when your legs give out before your CV system does. Or not. It'd be worth experimenting to see if it helps.

1. Not to be too blunt, but this particular forum is probably not the place you should be asking this question. I haven't found the quality of advice about power meters and their usage here to be especially high.

2. You've laid out your specific use case clearly and well. A power meter will probably help you learn to calibrate your RPE better, which appears to be your specific goal.

3. Slowtwitch may be a slightly better forum for you. If you get serious about this, the 4iiii may not fulfill all of your needs but for your existing stated use case it's almost surely fine. In fact, your usage isn't particularly demanding so for your specific case, something like a HRV-based meter could be just as fine, and it's cheaper. If your checkbook balance is high, of course, that may not matter.

4. Very nice. Sounds like your FTP is in the 5 watts/kg range.

OP, I can confirm that RChung is a legitimate expert in power meters, and his advice in this regard is worth more than anyone other responses here.

Thanks for the very detailed explanation of how power fits into running, [MENTION=193221]musicmaster[/MENTION]. Appreciated.

I think that's right. If you just want to go out and ride, then it doesn't matter. If you're into improving and getting more insight into your performance they are very helpful - not required, but extremely helpful and illuminating.

J.

I personally would suggest Garmin pedals because they can be easily moved from training bike to race bike to indoor trainer to spin bike even... across SRAM, Shimano, and Campy.... because they use the only interface that is still standard in the entire modern cycling universe.... 9/16 LH and RH threads.

Note: This is not what I personally use. I have crank based power meters. And I find the migration from GXP/Hollowtech to BB30 to BB86/PF30/wtf ever to be maddening. Also the inability to just swap full size 53/39 vs compact 50/34 vs cyclocross 46/36 is another aggravation. However, I don't plan to move away from crank based power meters at this time. In fact I may be picking up a 3rd one for a climbing specific build.

But for the money, Garmin pedals seem to offer the best combination of real measurement and flexibility / compatibility with wildly all over the map groupset standards.

Curious about whether OP intends to use perceived effort/power measurements initially to limit training stress, or mainly for benchmarking, or do you have a detailed training schedule in mind?

This is a useful observation to have made.

Once I got this through my skull it made certain intervals a bit less awful, and lets me focus on teaching myself to fix my pedaling technique during winter indoor training when there's nothing to do except listen for instructions from the coach and staring at the power number on my Garmin.

If a hard interval (CP30 test, any VO2max interval) feels harder than it should, now that I'm pretty confident in my pacing, I know to look at my technique rather than write off the day as not being strong that day. The difference between "pedaling squares" and "pedaling circles" is pretty dramatic in the data. You never really feel all that great doing hard intervals, so it can be easy to slip into a less efficient pedaling motion if you haven't practiced it much lately. You can waste a lot of watts fighting against the cranks.

If you go with a pedal-based power meter, go with PowerTap P1 instead of Garmin Vector. The Garmins require a torque wrench to install, the P1s don't. Technically you could install Vector pedals without one but if they're not torqued to spec (40 Nm?) they'll report the wrong power.

Cheers. I was just curious as to what you meant, since the word efficiency gets thrown around loosely all the time. I also find the feedback quite useful, although it is not for everyone necessarily (as Doge can attest to) and sometimes can even be counterproductive (just look at everyone obsessing over FTP and FTP only.)

No worries - sounds like we are on the same page. I'm an engineer by training so I tend to look at this from that persepctive.

I do agree that people get way too hung up on FTP. I also think that obsession can come from a lack of understanding of what the power meter is telling you and the physics behind it. If you are listening to your body at the same time you are evaluating your technique and performance, the power meter is invaluable for the feedback it provides.

J.

You're holding over 180 bpm for 2.5 hours at a time? That's insane.

It is feedback. I don't argue that. But just like charts and graphs it is deciding what needs to change and how to change it that is most important. Sure you have to be able to diagnose the "problem" but group rides and races can do that. The more a rider needs to solo ride the more important that data becomes as they don't have other means for feedback.

When my kid was in SoCal and riding with his coach and racing regularly there was really not time or use for a PM program and other than USAC coaches - nobody cared.
Now that he is remote and the only one around at his level it is a great tool to communicate to his coach (a new one) - and him, where he is at. But a Strava hill segment can do similar. And I watch both for entertainment value.

I just ordered a PM wheel for me for no other purpose that to look at the numbers and see how I decline with age. I can do the same with a weight, or push-ups. Just a PM is more fun. If I did desire to compete in cycling there are many things I'd do first before using power numbers. And then, when it was time to use them - I'd send them to a pro. Because just because I can lift a known weight a number of reps does not mean I know the best way to gain strength (although been in this space 40 years - I am a good guesser).

Helpful information. Not being a user, I wasn't aware of the torque wrench requirement. In fact, I wasn't even aware of the power tap pedals!

Rather than exclude them outright though, I'd probably just include the price of a torque wrench when comparing the Garmin and Powertap products.

I've never worn a HR monitor for a marathon, but here's a treadmill workout I did two years back with one one that was 2x5 mile at somewhere between 5:45-6 min/mile pace (goal marathon pace that year was 5:42). Ignore the pace/mile splits since the accelerometer is very inaccurate on the forerunner watches


https://connect.garmin.com/modern/activity/426033457

Everyone's HR is higher running than cycling. There's more whole-body muscular activity when running and that increases HR at the same intensity, intensity being measured compared to LTHR. LTHR is higher running. Whether you get a power meter or go by HR, you have to go through the same process of examining your data to set training zones or targets. Your running experience is of little value for that, since your HR will be different and you don't measure power when running.

Personally, I've found HR to be a fine measure for incorporating varied training activities Though each different activity uses different HR zones, I can set up the various zones vs. activities in TrainingPeaks to give me comparable numbers for training stress. IME measuring training stress is the most help when trying to modulate training. Joe Friel's Quick Guide to Setting Zones | TrainingPeaks

That said, I believe you can also figure training stress similarly between running and cycling by using power for cycling and pace for running, though running pace in hilly terrain will be very inaccurate, while HR will be quite accurate.

It can seem difficult to get one's HR up when one is very conditioned. I've found that it helps a great deal to do some early ride spin-ups/power intervals, say two 1-minute hard high cadence efforts with 5 minutes between.

Other commenters' admonishments about maintaining a high cycling cadence are well taken. 85-95 is usual for the flat and 75-85 usual when climbing. I'm not a tri guy, but I think 90 cadence is common for the bike leg.

More tri information in the Triathlon Forum.

That adds about $200. You can get a torque wrench much cheaper but not one that goes up to the spec the Garmin pedals require.

Also means if you're traveling and want to just bring your pedals instead of the whole bike, and rent a bike where you're going, you need to bring your wrench or have somebody install them for you.

I bought a pedal-based PM for the reason you mentioned, portability between bikes. In practice that's more limited than you'd think, and the P1 pedals are an improvement.

Both pedal-based meters require a specific cleat. You can move them back and forth between a road racing bike and a gravel bike (or even a MTB), but Keo cleats don't work very well on dirt roads if you ever put your foot down for any reason.

That's been my experience with them.

rTSS = (Pace / Threshold Pace) * Duration in minutes

Should be pretty familiar to any cyclist who uses a PM.

I don't have WKO but it has a "grade normalized pace" that's supposed to deal with hilly terrain.

Yes, what I'm saying. I for sure don't run uphill at my same minutes/mile pace while my HR does show the variation one would expect. IOW, running uphill my hrTSS would be higher, while my rTSS would be lower. I also don't use WKO so I can't comment on the accuracy.

On a practical note, I can record running hrTSS with my uploading Polar watch and load that into TP, while having also to record distance and elevation will require a GPS unit.

Ah yes... the road cleats only limitation. Another consideration.

FWIW, 40nm = 29 ft lbs = 348 in lbs.

$49 buys a really nice Craftsman 1/2 drive clicker torque wrench (10-100 ft lbs)

$22 gets a reasonable Duralast 3/8" one at Autozone (up to 960 in lbs) Duralast 3/8 in. drive torque wrench 79-141- Read1Reviews onDuralast #79-141

But I don't have any opinion on Garmin vs Powertap pedals :-)

[MENTION=68730]nycphotography[/MENTION]

I borrowed a t wrench the few times I've had to install my pedals. I've been meaning to buy one but haven't got around to it. You may have just saved me a lot of money. If you're ever in Seattle shoot me a note so I can repay you in beer.

Lots of 20% off coupons floating around right now. Good time to pick an expensive, usually-not-on-sale, item like a power meter.

Yes, rTSS uses Normalized Grade of Pace (NGP) to account for the terrain. While it is not perfect, they use rTSS rather than hrTSS because the TrainingPeaks/WKO guys think it is a more accurate measure. HR is incredibly responsive to changes in conditions (temperature, diet, mood, etc). While you can get away with using NGP on the run, pace on the bike is also, and probably more acceptable to changes in conditions than HR. This is why a power meter is much better than evaluating work than pace or HR on the bike.

OP, it is going to be a long time before your run HR and bike HR are at all near each-other. For most people run HR is higher by default, but with a decade of 70 MPW your run fitness is very developed. If you can run forever at 180+ bpm, but feel like you are gonna die at 160bpm on the bike, this is pretty normal. Running and biking are incredibly different.

Will a power meter help you? I think that a PM will help anyone and everyone that learns how to use it. Is it worth the cost? Assuming you are going to use it, it depends on your goals. If you are riding 1-2x per week as cross training (presumably to complement your 70+ MPW) then I am guessing you are using it for recovery, in which case, I don't think that it has a ton of value... Just go out and spin easy for an hour. If you are serious about a 70.3, then it will help you a lot in both training, but also during races. A triathlon is a time trail that you need to pace with the intent to run well off the bike. Having a power-meter to do that is a big advantage.

To weigh in on the running power meter discussion, I do think they will catch on and I think they will catch on big. I do not see an issue with the accelerometer based "power", it is proven to be pretty accurate. Running power however, is not at all like bike power. Higher bike power is ALWAYS better. Higher running power is not always better. Interestingly, it is also not necessarily the case that lower run power at a given pace is better. Right now we are in a spot where the technology has come out at an affordable price to record run power data. The question is, what do we do with that data. Jim Vance has done some of that analysis, and I know Andrew Coggan (of TrainingPeaks) consults for stride. I will be interested to see how run power gets integrated into programs like TrainingPeaks and onto head units like Garmin to provide realtime feedback and post run analysis. Once those principals start to become better understood I think we will see run power meters take off.

Bolded is the issue I currently have with running power. Even if they are 100% accurate, the question is "what do I do with these numbers?"

Earlier this year, I had gotten into a conversation with a representative from Stryd. The biggest thing he had pointed out was the advantage of "flattening hills" (similar to cycling) -- but in the running scene, only really trail races have any significant climbs that would need to be "flattened" -- most road races are pretty flat by nature (there are exceptions, of course), or are rolling and aren't enough to need to be normalized.

I then asked him, "So what about me -- someone who (at the time) lives in IL, which is pretty pancake flat, who is an experienced runner, has a training group, and knows what my limits are based on both perceived effort and pace?" The best he could respond with was the ability to be able to experiment with different running form and gaits to determine what was the most efficient -- essentially, a product I'd use for a week or two, learn from, then have little use for after.

I think with cycling, there's a clear use for power and a clear correlation for both your fitness level and for training goals. With running, it just isn't that clear right now. As you stated, more power isn't always better, and less power isn't always better either. So when it's not always either or, then how do you write a training plan based on a power number? I think as time goes on, there will be a lot more analysis on the subject. But in its current state, I really don't think it's worth the $$$ right now until they can reliably create a training plan focused around the power numbers.