yesterday I banged out a 30 min TT on my bike and got my polar to give me the average BPM for the whole session. I was under the impression that this was an ok test to determine my AT, but after looking around on the web this morning, I am not so sure…as there seem to be heaps of different protocols flying around.
What do you guys think of this test?
BTW, avg BPM 176. My Max HR in training is 204 and my MVO2 occurs at 184. So 176 does sound a little high when taken to a % of my MV02 I reckon.
Get a Power Tap, SRM, or Computrainer. The first two, in particular, will give you pretty accurate power readings and a more solid basis for training on the bike. Heart rate is highly variable, being dependent on a host of factors, e.g., hydration, temperature, humidity, training stage, etc.
I tell you what, as little as I know about aerobic energy systems, I do know that you can pump out a significantly higher than anaerobic threshhold heart rate, when you are only going at it for 30 mins, so my test, and the friel test do seem a little short.
Benno, your comment seems a bit counter-intuitive.
Given that your anaerobic threshhold (LTHR) is the point at which lactic acid clearance equals lactic acid production, it is unlikely that you could exercise for much more than a few minutes above your LTHR. Otherwise your blood would be full of lactic acid and you would blow (or at least slow down significantly).
Perhaps the answer is that your LTHR is higher than you think.
Roy, your description of what the LTHR is the same as my understanding of it, but I would dispute the notion that you can only exercise for a few minutes above threshold, before blowing up or slowing down. I would consider (the speed of) the effect of Lactic acid to be fairly variable dependent on an individuals training adaptations (lactic tolerance), mental strength, training adaptions etc.
Anyone doing a 10k run race , or 30 min bike TT is going to be moving at a fair way above their LTHR. It is this ability to exercise for short periods above LTHR, that a LTHR test is supposed to iron out (IMO) to allow an accurate measurement to be taken.Thats why in hindsight I consider 30 mins a fairly short test.
Hey, I hope I’m wrong and your right though, because if the figures are accurate, then my LTHR is 95% of my MV02! SHyeah!
Perhaps the answer is that your LTHR is higher than you think.
Very likely. This is why power measuring tools are invaluable for this sort of analysis. If done correctly by maintaining power in a narrow band maintainable for no more than 30 minutes, a 30min TT will produce a very accurate approximation of your LTHR by taking the average over the last 20min. Using HR alone is not as accurate due to the lag time in HR vs effort. If you yo-yo your power like most riders will do without power feedback, your avg heart rate may be lower, but your avg power output, and consequently your performance will not be what it could be. Consequently you’ll end up training at lower heart rates than you could be, hindering your development.
“b) Time Trial: most commonly used, but also misinterpreted. This method is described by Joe Friel: perform a 30 minute time trial, as if in a race. Pace your effort so that you don’t die too soon, or finish with too much gas. At 10 minutes, hit the split button on your heart rate monitor to record your average heart rate over the last 20 minutes of the test. This average heart rate is an estimation of your LTHR. However, there is a problem here. If you use the Conconi method above, and then use the Time Trial method, you can often experience a difference of 4-12 beats per minute between the two tests. Depending on the athlete’s conditioning, mental state, motivation, pain tolerance, etc, it is possible to maintain a heart rate well above your LTHR for a considerable amount of time. For example, I’ve tested myself on my Computrainer several times and am confident that my LTHR is about 172-174 bpm. However, I can do a climbing trial and average 183 for 40 minutes. I can do a sprint tri and average 180+ for 55 minutes”
The author goes on to apply some fudge factors for “experience” to the different methods to get the LTHR to come out to the number he wants. The disagreement comes from being at your LTHR or being slightly above it and your ability to suffer. All in all, as long as you make an attempt to repeat the conditions in subsequent tests, it probably doesn’t matter too much. It also depends on how you got your VO2 tested. That could be low.
Benno, I agree that there is likely to be a variation in how long various individuals can continue to exercise at intensity above their LTHR. However, I would be surprised if that range extended to 30 mins.
As Mike suggested, I’d be inclined to review your av HR for the last 20 mins of the test.
Alternatively, perhaps your VO2 max figure wasn’t properly calculated?
“Depending on the athlete’s conditioning, mental state, motivation, pain tolerance, etc, it is possible to maintain a heart rate well above your LTHR for a considerable amount of time. For example, I’ve tested myself on my Computrainer several times and am confident that my LTHR is about 172-174 bpm. However, I can do a climbing trial and average 183 for 40 minutes. I can do a sprint tri and average 180+ for 55 minutes”
Exactly what I was looking for.
My MV02 test was done in a lab with the mask and all with all the gas measuring things :-),…however it was done on a running treadmill so the reading was obviously valid only for a specific sport/movement. Which was, BTW, 54.5
As Mike suggested, I’d be inclined to review your av HR for the last 20 mins of the test.
I’d love too, but from memory, my heart rate was over 175 and got up to 186 for the last 20 mins, so that would calculate my LTHR to an even higher % of MV02, and a generally really high BPM figure for a 26 yr old 6ft 3,92kg, which is why it sounds so wrong…to me.
Just FYI, it was a long straight road I was on, and I was trying to pace the whole thing and maintain a fairly even power output the whole way, whilst staying above 170 for the first 10 mins, and letting it really burn the last 20.
I guess I sounds like I am trying to disrepute the legitimacy of the 30 min TT protocol, and maybe I am…cause I find it hard to believe that I can exercise aerobically at 170bpm on bike. Which is how I understand it to mean. I was feeling a fair bit of pain during that test.
I guess this is where Perceived Exertion comes in, and what they say about formulas being a good guide, but not set it stone.
Normally I do my long rides (5 hrs) at 135, and come home pretty wiped.I can’t imagine that I would make it anywhere near 5 hours near 170 bpm.
BTW, I really appreciate your discourse on this guys
“Similarly, heart rate at LTV (lactate threshold velocity) exhibited a rather large natural variation . In fact, the research suggested that athletes should expect the heart rate associated with a specific LTV to vary by up to 12 to 18 beats per minute from one day to the next! This rather large natural variation in heart rate presents problems for those who believe they have identified a “lactate threshold heart rate” and who are carrying out training at that specific heart rate, believing it will be beneficial for LTV enhancement. In fact, it would not be unreasonable to expect that the heart rate which the athlete had “tied” to LTV might be up to 18 beats “off” the true LTV ticker rate!”
Owen Anderson - “Bad News For Lactate Lovers:…”
Running Research News - Volume 18, Issue 7, Sept. 2002
Lactate threshold, is usually defined within scientific literature as a 1mmol increase in lactate over baseline levels. The power (bike) or velocity (run) at this point can be sustained for a long period of time (bike = couple hours plus).
The effort (power output) that you can sustain maximally for ~ 1-hour, is likely to be significantly higher than LT (~20% plus). It’s also highly unlikely that lactate will remain constant during a TT if you are giving it all (in a study i took part we had lactate measured every 5 mins during a 1-hr TT, and the mean lactate went from ~@ 3 mmol to 7 mmol during the effort – even though power output was kept constant).
Trying to specify a HR that occurs at LT is generally going to be hard as, as others have pointed out it can vary quite dramatically depending on such variables as ambient temperature, fatigue, stress, hydration status, etc.
Therefore, it is possible to go way over “LTHR” for a long period of time, providing you can maintain the power output (or velocity in running). HR is a very poor indicator of what is going on.
