Power or HR on the trainer?

Gav888

Hi Guys,

I have had a search but I cannot find what I am looking for so hope you can help.

At the moment with all the sh*ty weather I have been doing a lot of turbo trainer time but I have always wondered something. If I am doing power zone 4, so threshold work at approx 95%-100% of my FTP, I can feel it in my legs, but my heart rate is typically zone 3 and stays steady at that HR, even when using a big fan or even not using a fan (as some people have said HR is higher without a fan).

I know people have mentioned use power in this situation, but why, for adaptions to happen, ie increasing my FTP, shouldn't my HR be in zone 4 as well (after all cycling is aerobic) as my legs being in power zone 4 will be a muscular workout instead of an aerobic one, if that makes sense?

FYI I am using % MHR rather than % LTHR.

Could someone explain this for me please?

Thanks.

Trev The Rev

Gav888 wrote:

Hi Guys,

I have had a search but I cannot find what I am looking for so hope you can help.

At the moment with all the sh*ty weather I have been doing a lot of turbo trainer time but I have always wondered something. If I am doing power zone 4, so threshold work at approx 95%-100% of my FTP, I can feel it in my legs, but my heart rate is typically zone 3 and stays steady at that HR, even when using a big fan or even not using a fan (as some people have said HR is higher without a fan).

I know people have mentioned use power in this situation, but why, for adaptions to happen, ie increasing my FTP, shouldn't my HR be in zone 4 as well (after all cycling is aerobic) as my legs being in power zone 4 will be a muscular workout instead of an aerobic one, if that makes sense?

FYI I am using % MHR rather than % LTHR.

Could someone explain this for me please?

Thanks.

How are you measuring power? Are you sure you are measuring the power correctly? Some people do find it harder to get their heart rate up as high indoors as they do outdoors this may be because cycling outdoors is more stochastic than indoors on a trainer. Poke up the resistance and get out of the saddle a bit and put some force into the pedals this might poke up the heart rate, it may be you are not in fact producing the power you think you are.

If you can measure power correctly I see no reason why you should not use power. But you need to make sure you have the zones worked out correctly. Some use different numbers for indoors because they find their power is different on a turbo to outdoors.

xscreamsuk

Maybe you are getting fitter and your FTP is higher than you think? When did you last test it?

SBezza

HR is just a response to intensity, it is not having a high HR that drives adaptions. If you have a reliable power measuring device use that. If it is turbo power, then perhaps HR might be a better option unless you can ensure the figure it gives out is repeatable over the duration of use and across different sessions on different days.

Zone 4 is still aerobic, not until you get to Zone 6 and above would it be anaerobic.

Trev The Rev

SBezza wrote:

HR is just a response to intensity, it is not having a high HR that drives adaptions. If you have a reliable power measuring device use that. If it is turbo power, then perhaps HR might be a better option unless you can ensure the figure it gives out is repeatable over the duration of use and across different sessions on different days.

Zone 4 is still aerobic, not until you get to Zone 6 and above would it be anaerobic.

It would be difficult to ride at a high intensity without a corresponding high heart rate. If the blokes heart rate is not getting up to speed would he not be generating the required power?

Gav888

Last test for my power zones was 2 weeks ago, but I would be surprised if my fitness has increased that much to drop an entire zone for HR, plus my legs still feel knackered.

As for standing and sprinting for a bit, it does raise my HR but then it drops back down again once I sit down.

Power is from a turbo I have, so accuracy is debatable but its all I have, I can hit the same numbers when doing 2x20 for example using the zones I setup 2 weeks ago and my legs feel like they had a good workout. These zones are from http://www.trainingbible.com/joesblog/2 ... zones.html.

If HR is just a response to intensity, it makes me think that my Z4 power levels are not right even though they feel right as I am not hitting Z4 HR.... but I guess if I am following the above testing for my zones then it 'should' be correct and its just the fact that HR indoors will always be lower?

I can hit Z4 HR on the road no problem but as I dont have a power meter on my bike I cannot compare indoors to outdoor power levels, I just want to be sure I am hitting the right levels indoors and not actually be working out less than I think I am because my HR is a zone lower than expected.

Alex_Simmons/RST

Gav888 wrote:

FYI I am using % MHR rather than % LTHR.

How did you established your MHR?

and/or are you capable of actually riding at a higher power than you are?

SBezza

Trev The Rev wrote:

SBezza wrote:

HR is just a response to intensity, it is not having a high HR that drives adaptions. If you have a reliable power measuring device use that. If it is turbo power, then perhaps HR might be a better option unless you can ensure the figure it gives out is repeatable over the duration of use and across different sessions on different days.

Zone 4 is still aerobic, not until you get to Zone 6 and above would it be anaerobic.

It would be difficult to ride at a high intensity without a corresponding high heart rate. If the blokes heart rate is not getting up to speed would he not be generating the required power?

Not really, I have done hard workouts with a depressed HR, so it is perfectly possible to output the power and your HR not be in the corresponding zone.

Now if it was happening all the time I would suspect something is not right, but if it is a one off, or is happening when tired, it may not be a low reported power issue.

Trev The Rev

Gav888 wrote:

Last test for my power zones was 2 weeks ago, but I would be surprised if my fitness has increased that much to drop an entire zone for HR, plus my legs still feel knackered.

As for standing and sprinting for a bit, it does raise my HR but then it drops back down again once I sit down.

Power is from a turbo I have, so accuracy is debatable but its all I have, I can hit the same numbers when doing 2x20 for example using the zones I setup 2 weeks ago and my legs feel like they had a good workout. These zones are from http://www.trainingbible.com/joesblog/2 ... zones.html.

If HR is just a response to intensity, it makes me think that my Z4 power levels are not right even though they feel right as I am not hitting Z4 HR.... but I guess if I am following the above testing for my zones then it 'should' be correct and its just the fact that HR indoors will always be lower?

I can hit Z4 HR on the road no problem but as I dont have a power meter on my bike I cannot compare indoors to outdoor power levels, I just want to be sure I am hitting the right levels indoors and not actually be working out less than I think I am because my HR is a zone lower than expected.

Many riders can't hold the same power on a turbo as they can on the road. Many factors and much disagreement as to why, but my gut instinct is it is because the turbo stresses the muscles and the parts of the muscles differently in a more monotonous way. You are stuck in exactly the same position, same force, same cadence and this stresses the legs more or differently. There might be more resistance through the whole pedal stroke on the turbo than on the road so the muscles are used for more of the stroke. On the road there is more variability to force and cadence due to undulations wind etc. Also pedaling just feels different on a turbo so you use the muscles differently.

If you are unsure as to the accuracy or repeatability of the power numbers I would not use them.

If your heart rate goes up when you stand and sprint a bit then drops again when you sit you have proven you are not generating as much power sitting as you might think.

Is your cadence and force the same on the turbo as on the road? I find I drift to a much higher cadence on a turbo than I naturally use on the road.

Gav888

Alex_Simmons/RST wrote:

Gav888 wrote:

FYI I am using % MHR rather than % LTHR.

How did you established your MHR?

and/or are you capable of actually riding at a higher power than you are?

For MHR, I found a long hill and rode up it as hard as I could, then when I couldn't max out my HR anymore seated I sprinted until I was f**ked and then used this as my MHR, so it might be that its low compared to what a true MHR test is....?

As for riding at a higher power, yes, but for shorter intervals, for example when doing 5x5, but I havent actually tried doing 2x20 at a higher level than 100% FTP as I did my last test 2 weeks ago.... it might be that on that day I wasn't at my 'freshest' to get the highest levels possible so the test was below par?? but isnt that why you have a zone of 90% to 104% for Z4 to take into account 'freshness' when doing your zone testing, or should you be doing multiple tests and then averaging that?

Gav888

Trev The Rev wrote:

Gav888 wrote:

Last test for my power zones was 2 weeks ago, but I would be surprised if my fitness has increased that much to drop an entire zone for HR, plus my legs still feel knackered.

As for standing and sprinting for a bit, it does raise my HR but then it drops back down again once I sit down.

Power is from a turbo I have, so accuracy is debatable but its all I have, I can hit the same numbers when doing 2x20 for example using the zones I setup 2 weeks ago and my legs feel like they had a good workout. These zones are from http://www.trainingbible.com/joesblog/2 ... zones.html.

If HR is just a response to intensity, it makes me think that my Z4 power levels are not right even though they feel right as I am not hitting Z4 HR.... but I guess if I am following the above testing for my zones then it 'should' be correct and its just the fact that HR indoors will always be lower?

I can hit Z4 HR on the road no problem but as I dont have a power meter on my bike I cannot compare indoors to outdoor power levels, I just want to be sure I am hitting the right levels indoors and not actually be working out less than I think I am because my HR is a zone lower than expected.

Many riders can't hold the same power on a turbo as they can on the road. Many factors and much disagreement as to why, but my gut instinct is it is because the turbo stresses the muscles and the parts of the muscles differently in a more monotonous way. You are stuck in exactly the same position, same force, same cadence and this stresses the legs more or differently. There might be more resistance through the whole pedal stroke on the turbo than on the road so the muscles are used for more of the stroke. On the road there is more variability to force and cadence due to undulations wind etc. Also pedaling just feels different on a turbo so you use the muscles differently.

If you are unsure as to the accuracy or repeatability of the power numbers I would not use them.

If your heart rate goes up when you stand and sprint a bit then drops again when you sit you have proven you are not generating as much power sitting as you might think.

Is your cadence and force the same on the turbo as on the road? I find I drift to a much higher cadence on a turbo than I naturally use on the road.

I find that when I stand to get my HR up, then my legs build lactate quickly so I have to sit down again, but it proves my HR will rise... as for cadence and force, cadence is roughly the same on road as to the trainer, around 90rpm. As for comparing force, I cant as I dont have a power meter on the bike, but RPE feels about the same....

So I can be doing 2x20 for example, showing power z4 and rpe feels right in what my legs are telling me but I look down and see HR is only z3. I guess from my knowledge its either HR is lower in doors or rpe is actually higher indoors and my power is actually lower than what I think it is.

Another way of looking at it, is there any accurate way to setup my zones given the tools I have, which is a Edge 305 for HR and a turbo with a power meter on it... I know a power meter on my bike would be ideal but too expensive.

Trev The Rev

SBezza wrote:

Trev The Rev wrote:

SBezza wrote:

HR is just a response to intensity, it is not having a high HR that drives adaptions. If you have a reliable power measuring device use that. If it is turbo power, then perhaps HR might be a better option unless you can ensure the figure it gives out is repeatable over the duration of use and across different sessions on different days.

Zone 4 is still aerobic, not until you get to Zone 6 and above would it be anaerobic.

It would be difficult to ride at a high intensity without a corresponding high heart rate. If the blokes heart rate is not getting up to speed would he not be generating the required power?

Not really, I have done hard workouts with a depressed HR, so it is perfectly possible to output the power and your HR not be in the corresponding zone.

Yes me too, and it is things like that which are so interesting, but in my case not by more than 10 bpm, but generally all things being equal, you are not going to do 250 watts one day and 300 watts the next and find heart rate lower at 300 watts than you did at 250 watts.


Many people set different zones for indoors on the turbo. Be these power zones or heart rate zones. As you don't have a real power meter I would go opt for heart rate. You can still have fun with the power numbers at the same time.

Gav888

Trev The Rev wrote:

Many people set different zones for indoors on the turbo. Be these power zones or heart rate zones. As you don't have a real power meter I would go opt for heart rate. You can still have fun with the power numbers at the same time.

That is a pain in the back end then, having 2 sets of HR zones but saying that, how do you know if by using HR it isnt a 'bad day' for HR that your having, so if for example I do the 30min test, and my LTHR is 180 and my power reads 250W. Then I repeat the test in a couple of days and my LTHR is 170 but my power is still 253W.

How do you get an accurate HR for the zones as it can fluctuate from day to day, hence why I thought power was a better option for me, although not as accurate as its only turbo based, but then potentially neither is HR that accurate lol

Trev The Rev

Gav888 wrote:

Trev The Rev wrote:

Many people set different zones for indoors on the turbo. Be these power zones or heart rate zones. As you don't have a real power meter I would go opt for heart rate. You can still have fun with the power numbers at the same time.

That is a pain in the back end then, having 2 sets of HR zones

Having said that your max heart rate is still your max heart rate, so you will be setting indoor training zones which are workable indoors, rather than setting new zones.

I don't want you to re set everything so you are poncing about without putting the effort in. You still need to get the power and heart rate up into a zone where it is doing some good.

Gav888

How do you know if by using HR it isnt a 'bad day' for HR that your having, so if for example I do the 30min test, and my LTHR is 180 and I check my power after and it reads 250W. Then I repeat the test in a couple of days and my LTHR is 170 but my power is still 250W.

How do you get an accurate HR for the zones as it can fluctuate from day to day, hence why I thought power was a better option for me, although not as accurate as its only turbo based, but then potentially neither is HR lol

twotyred

Three possibilities. Either your power zones are wrong or your HR zones are wrong or they're both wrong.

Next time you are doing a threshold turbo session of 20 min or longer if after 10 mins or so your HR still isn't into what you think the threshold zone should be then pedal harder until it is and see if you can sustain that effort for the whole interval. If you can then you've found out what your proper threshold HR is (or near to it). Having got that and as you haven't got a reliable method for power measurement I'd say forget power and just work on heart rate especially as you have no power measurement on the road. If you concentrate on just using HR you'll eventually get a good feel for what your zones should be without having to do a regular max HR test which I think are always suspect unless you have someone motivating you. OK HR isn't much good for shorter intervals but its fine for 2 x 20 or longer.

Personally my power and HR zones match up and I had my HR zones worked out long before I got a power meter.

Trev The Rev

Gav888 wrote:

How do you know if by using HR it isnt a 'bad day' for HR that your having, so if for example I do the 30min test, and my LTHR is 180 and I check my power after and it reads 250W. Then I repeat the test in a couple of days and my LTHR is 170 but my power is still 250W.

How do you get an accurate HR for the zones as it can fluctuate from day to day, hence why I thought power was a better option for me, although not as accurate as its only turbo based, but then potentially neither is HR lol

Heart rate does fluctuate, but not by as much as some would have you believe. You should set heart rate zones from a max heart rate test which should be done when rested and fresh and doing the same sport. You maximum heart rate does drop with age but in a well trained athlete no where near as much as the usual formulas. Mine has dropped only 5 beats on 20 years.

I trained with power and heart rate for decades and I found heart rate followed power remarkably accurately. Whenever I saw a lower heart rate than usual for the same power I was able to raise the power and heart rate to a level I knew was sustainable. Whenever I saw a heart rate that I knew to be unsustainable for the desired time and I held the power because the power was 'doable', I was unable to hold that power or in serious difficulty holding it.

A lower heart rate for a given power predicted an improvement in fitness which was proven in test after test. Lower heart rate for a given power always showed improvement I never once got improvement following a higher heart rate for a given power.

Only once did my heart behave oddly and unpredictably - and that was when I got a serious illness.

Heart rate does vary, slightly and predictably. I always found the power zones and heart rate zones correlated very narrowly.

The only times I have found heart rate and power not to correlate closely, (other than when I had a serious illness) was when the power meter has subsequently been proven to be inaccurate.

Unless you are using a real power meter which is properly calibrated and known to give accurate figures throughout the entire power range you would be better off using heart rate.

Sadly because too many people look mostly at power, they assume the power is always correct and that it is the heart rate which is variable. Very often it is the power meter which is duff not heart rate. And for those that don't use heart rate at all and rely only on power - you better hope your power meter is as accurate as you think it is.

Gav888

Ok, thanks for all the advice guys its clarified what I wanted to know, not really what I wanted to hear having spent out on a turbo with power as I thought it was the way to go with training, still, you learn

One last question, should I stick with MHR or change to LTHR?

Trev The Rev

Gav888 wrote:

Ok, thanks for all the advice guys its clarified what I wanted to know, not really what I wanted to hear having spent out on a turbo with power as I thought it was the way to go with training, still, you learn

One last question, should I stick with MHR or change to LTHR?

Provided you control the variables there is no reason why you should not use the power on the turbo. Just accept the numbers may not be 'real' but you should be able to make them repeatable so you can see improvement. The feature is still useful and fun to use.

I would base things on max heart rate. LTHR should move as you get fitter.

Gav888

lol ok, so you would recommend:

1- Ignore HR indoors, providing power is setup correctly then you are getting the adaptions as expected?
2- Setup the power levels by doing a 30min TT, the average power is my FTP for my zones?
3- Setup MHR by riding a hill as hard as I can until my HR wont go any higher, then sprinting all out until I can do no more, the highest HR is my MHR for my zones? Or is it safer to do this on the trainer as less chance of being killed

Trev The Rev

Gav888 wrote:

lol ok, so you would recommend:

1- Ignore HR indoors, providing power is setup correctly then you are getting the adaptions as expected?
2- Setup the power levels by doing a 30min TT, the average power is my FTP for my zones?
3- Setup MHR by riding a hill as hard as I can until my HR wont go any higher, then sprinting all out until I can do no more, the highest HR is my MHR for my zones?

I would base everything on max heart rate then you can use heart rate indoors & outdoors and that data will always be useful.

Use the power function on the turbo but accept that data might not be of any use on any other machine. Accept that performance on turbo is different to outdoors.

If and when you get a real power meter train with power and heart rate. You will have to use heart rate anyway whenever the power meter is malfunctioning or not working at all or being calibrated or at the manufacturers being fixed. The heart rate data also becomes useful when you discover the power meter you have been using for the past year was giving erroneous data all along and all your power meter data is totally worthless and all those hours spent analysing said data was a complete waste of time.

Gav888

Thanks Trev The Rev for all your advice today, its very useful.

My only concern with using MHR indoors is that I have found that I usually cannot reach Z4 HR indoors and have to kill my legs just to get into the zone, let alone maintain it for 20min. On the road I can hold Z4 for the 20min and repeat it.

Should I have a MHR for indoor workouts and a MHR for outdoor workouts to solve that, keeping the zones the same so I only adjust my MHR depending on the workout im doing (indoors or outdoors) and keep the zone % the same? I think one of the coaches said something about MHR is sports specific, does that include road vs turbo work?

Or should MHR be MHR regardless of indoors or outdoors?

Trev The Rev

Gav888 wrote:

Thanks Trev The Rev for all your advice today, its very useful.

My only concern with using MHR indoors is that I have found that I usually cannot reach Z4 HR indoors and have to kill my legs just to get into the zone, let alone maintain it for 20min. On the road I can hold Z4 for the 20min and repeat it.

Should I have a MHR for indoor workouts and a MHR for outdoor workouts to solve that, keeping the zones the same so I only adjust my MHR depending on the workout im doing (indoors or outdoors) and keep the zone % the same? I think Friel said something about MHR is sports specific, does that include road vs turbo work?

Or should MHR be MHR regardless of indoors or outdoors?

In my opinion you can only have one max heart rate per sport and even then max heart rate evens out when you are trained in each sport to the same sort of level. Runners switching to cycling find it hard to get as high on a bike at first. Same for rowers. If you really try you should be able to hit the same max indoors as outdoors. It is just your legs are not capable of pushing your cardiovascular system as hard on the turbo as on the road.

Just accept you can't perform the same way on a turbo (yet) as on the road. You might find in time your performance on the turbo starts to get nearer road performance.

As for finding my comments useful, remember my views are not orthodox, in fact many find them heretical.

Simmotino

Trev The Rev wrote:

As for finding my comments useful, remember my views are not orthodox, in fact many find them hysterical.

FTFY

Gav888

Just to give you an idea of what I am seeing.

Currently using MHR, which was tested on the road and its 200bpm at my max on that day, top of my Z3 HR is 166bpm.

Below is a pic of a 4x10 workout I did. 10min warm up ramping up the power then just holding it at the top end of Z3 for the intervals, you will see that my power (in blue) is fairly constant at that level and I found it ok to hold the power at that level, but my HR (in red) only gets to that level in the last 5min of the last interval....



Its the same situation when doing Z4 work.

Trev The Rev

Gav888 wrote:

Just to give you an idea of what I am seeing.

Currently using MHR, which was tested on the road and its 200bpm at my max on that day, top of my Z3 HR is 166bpm.

Below is a pic of a 4x10 workout I did. 10min warm up ramping up the power then just holding it at the top end of Z3 for the intervals, you will see that my power (in blue) is fairly constant at that level and I found it ok to hold the power at that level, but my HR (in red) only gets to that level in the last 5min of the last interval....



Its the same situation when doing Z4 work.

I would say that was normal, heart rate would lag behind like that, it just took until the last interval for heart rate to catch up. It would have happened sooner without the rests.

Gav888

Yep, I have found that when doing 1hr Z3 for example, the last 20min is in Z3.

BUT, if I was using HR only for the above workout my power levels would be a lot higher to get my HR into Z3 and as each interval was completed the power level would be less and less as my HR got higher and higher, so I could be doing power Z5 for the first 10min, then Z4 for the next, if you see what I mean, just to get my HR high enough.

But using power for these workouts indoors its nice and neat as above, but HR lags behind. On the road the above workout is different as I can easily get HR into Z3 and keep it there, then repeat it after the short rest period, HR just doesnt respond the same indoors as outdoors (for me anyway).

SBezza

Trev The Rev wrote:

Gav888 wrote:

Just to give you an idea of what I am seeing.

Currently using MHR, which was tested on the road and its 200bpm at my max on that day, top of my Z3 HR is 166bpm.

Below is a pic of a 4x10 workout I did. 10min warm up ramping up the power then just holding it at the top end of Z3 for the intervals, you will see that my power (in blue) is fairly constant at that level and I found it ok to hold the power at that level, but my HR (in red) only gets to that level in the last 5min of the last interval....



Its the same situation when doing Z4 work.

I would say that was normal, heart rate would lag behind like that, it just took until the last interval for heart rate to catch up. It would have happened sooner without the rests.

Agree with Trev, 10 mins is too short an interval really to determine what your HR is doing compared with the power. For the power you are holding your HR is increasing all of the time as you would normally expect it to do, if you had done 20 min intervals it would more than likely reached Z4 HR as well.

Gav888

Ah ok, so maybe I am using this wrong then.... but even so, if I was doing a 20min Z4 interval by HR alone, so I do the 10min warmup and my HR is Z2 or Z3 by the end of it, then I start to hammer it to get to Z4 HR I will be going too hard to get my HR up at first.

Should I be using a combination of Power and HR whilst on the turbo, so hold power at Z4 until my HR reaches Z4 then use HR to judge intensity until the interval is over, then repeat for the next intervals?

SBezza

Gav888 wrote:

Yep, I have found that when doing 1hr Z3 for example, the last 20min is in Z3.

BUT, if I was using HR only for the above workout my power levels would be a lot higher to get my HR into Z3 and as each interval was completed the power level would be less and less as my HR got higher and higher, so I could be doing power Z5 for the first 10min, then Z4 for the next, if you see what I mean, just to get my HR high enough.

But using power for these workouts indoors its nice and neat as above, but HR lags behind. On the road the above workout is different as I can easily get HR into Z3 and keep it there, then repeat it after the short rest period, HR just doesnt respond the same indoors as outdoors (for me anyway).

It is fairly easy to get to a HR zone and keep it there, just in getting there quickly you will be doing well over your target power. Adaptions are driven more by the maximum power you can sustain for a given duration rather than what your HR is doing. As Alex has said many times, longer intervals are fairly self correcting, either by power or effort in that if they seem a little too easy up the effort/power, if you can't complete a given duration, ease back slightly.

With a Z3 ride, as the HR is generally lower once at a level it stays around the right level, and even when using power on the road. Even though power will be up and down due to terrain etc, HR can remain fairly static. If you did a Z3 session on the turbo at a set power, again you would see a slow rise in HR over the duration of the session. Basically outdoors effort/power changes constantly, indoors on the turbo it is fairly static, so the HR traces would be different.

twotyred

Gav your HR data is entirely normal and exactly what I would expect, from your earlier posts I didn't realise it was only at the start of the intervals you thought the HR was too low. As you have found out HR is a lagging indicator which IMHO makes it nearly useless for judging intensity at intervals less than 20 mins. As you point out there is always the danger of overcooking your start to get your HR to where you think it should be leaving you unable to maintain that intensity for the rest of the interval. For short intervals on the turbo I'd recommend using speed as a proxy for power or if you think the power meter on your turbo is consistent then use that as an indicator to guage your intensity.

It could be you are warmed up more effectively on your road sessions which makes your HR respond faster.