I’ve heard a bunch of different ways on estimating bike LT, and i’m not sure which one is the best estimate. Here are the methods i’ve heard of (that i can do… I dont have a computrainer)
Friel: not a great definition in the training bible
Strauss: Ave HR for last 20 mins of a 30 min time trial
Ave HR for 1 hr time trial
others?
so what is the best/most accurate estimate that people have found?
Another way is the Conconi Step test - typically I use the 30 minute TT with my athletes.
Conconi:
You’ll need an assistant, a home trainer, and way to measure wattage or speed. A Cateye CycloSimulator, a Tune PowerTap, an SRM, or a CompuTrainer are all effective tools for measuring wattage, which is the preferred and more accurate method. If you are measuring speed, you’ll need your computer set up so that it takes the measurement from the back wheel. It’s also better to use a magnetic resistance trainer when measuring speed. With wattage, one can see very specifically the set, linear increase in resistance. With speed, you’re trying to estimate wattage. A windtrainer’s resistance increases exponentially as the speed increases, and feels more like riding outdoors. A magtrainer’s resistance will increase linearly as the speed increases, and is more effective for this kind of test.
Warm up at a comfortable pace for 10-15 minutes, and have your assistant note the wattage or speed you settle in at. This will be your starting point for the test
Increase your wattage each minute by 15 watts, or 10 watts if you are a smaller rider, holding steady by +/-5 watts. If you are using speed, increase by .5 miles/hour. One way to make that easier is to put 2 magnets on your wheel at opposite points to double the readout on your computer, and then increase by a full mile/hour. Shift gears when you need to, but focus on maintaining a steady cadence of +/- 90 RPMs. The test is over when you can no longer maintain the wattage. You should try to go to failure.
Once you’ve collected the data, you can determine your lactate threshold by taking into account a few factors: the point at which breathing becomes labored (or Ventilatory Threshold), the total length of the test, and the results of graphing the test. You should just mail me the test data, but I’m trying to teach you how to do this, so…
When you graph the test, your horizontal axis should be the minutes of the test. Start from the right with the final minute of the test, and use 2 blocks of standard graph paper for each minute. Your vertical axis should be heart rate, with every 2 blocks equaling 5 beats. Record every point of heart rate data on the graph. What you’re looking for is a mostly linear increase in heart rate until somewhere in the last 5 minutes of the test. At that point you’re looking for a plateau or pulling away of the heart rate line, often, but not always, followed by a spike in the heart rate. The start of that plateau or pulling away is normally an accurate estimate of your Lactate Threshold. It’s unusual for anyone to ride more than 5 minutes over their threshold in this test, which helps you narrow down the area to look (and corresponds with what we know about High and Middle intervals. High is your longest anaerobic effort and should be 2-4 minutes long. Anything over that length and you’re venturing into Middle, and an aerobic interval.) Also, the onset of heavy breathing will normally occur very close to the threshold point.
Mike Ricci
I have heard that wind trainers are more linear. Fluid seems to be the worst, too easy when going slow, then they load up and are impossible.
the best method is the one you mentioned you couldn’t do because of not having a computrainer. So, it sounds like you’re familiar with it, if not, check Joe Friel’s books out. I was faced with the same problem last year of not having a computrainer. I went and used a bike at a gym with wattage. The problem with that is they might be off in wattage and may vary from test to test after being used and abused. Also, position and fit are a lot different than my tri bike. I just made sure I stayed as close to a tri position as I could and that I used the same bike everytime. If that doesn’t work, are there any universities around with an exercise science dept.? They may have a computrainer or an ergometer that is accurate. They’ll charge you though.
I have read that the real-world best example is the average HR for a one hour TT effort. Same for running. Note as you get fitter obviously this will change and it will become a higher and higher percentage of your max HR.
The Friel test is the same as the Strauss test. I just did it last night. The results are spookily similar month after month. The only way mine changes much is when the weather is very cool or very hot.
Lactate threshold is usually defined within peer reviewed research as 1 mmol increase in lactate over baseline level. It’s also measured invasively, by taking blood samples and a corresponding power output (bike) or velocity (run) is recorded. LT is never a measure of HR.
However, that being said, the athlete and sometimes coach (:-() definition of LT is the maximum amount of work that can be achieved in 1-hr or the average power output or average speed (running). For most athletes, this will be about 20% above your true LT work level.
The Conconi method has been refuted in peer reviewed scientific journals, because such a deflection point exists in very few athletes. There’s also considerable difficulty in accurately assessing the deflection point when it does exist – as researchers don’t identify the same point in each person. see http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9293415&dopt=Abstract and http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8776209&dopt=Abstract as examples.
Using an incremental test to exhaustion is fine to estimate approximately where your TT power output might be, simply because, everyone TTs at around the same percentage of maximum aerobic power irrespective of fitness. However, this will give you a wide(ish) range, see, http://www.cyclingnews.com/fitness/?id=powerstern
However, if you want to know what your power is for a ~1hr TT, then the best thing is to undertake a 1hr TT!!
I would steer clear of using a Cateye to base too many results on, because they’re not reliable enough – the power displayed alters over time, as the units wear out, and there’s no way you can compare one cateye to another as they all give different readings. They are a nice feeling trainer though.
It’s also vitally important to realise that your result from an incremental test to exhaustion is very much protocol dependent. Using a 15 W/min ramp rate, will give a totally different answer to using a 25 W/min ramp rate.
As a last resort HR avg from a 1-hr TT is reasonable, but, HR does vary for many reasons (e.g., too much caffiene, anxiety of competition, temperature, hydration status, etc), which is why for cycling a more solid measure, i.e., power is far better.
Ric