Careful interpretation of specifically chosen lactate tests can tell you more than just your anaerobic threshold. Improper nutrition will affect the curve, increased / decreased technical efficiency will affect the curve, etc.
However, the relationship between acidity levels in the muscle (as estimated though blood lactate) and performance is what we end up looking at. To get faster there are two main parameters associated with iAnT;
- The percentage of peak HR you can hold at iAnT, and
The associated percentage of peak speed
In your lactate profile there are some expected changes with training;
- When you do good quality easy distance training, the lactate levels at low intensity will drop as will the lactate levels at high intensities. Your low intensity speeds (up to and possibly slightly beyond iAnT) will increase, but your supra-maximal speeds will probably decrease.
When you do high intensity training (above iAnT) you will expect your high intensity lactate values to increase along with your high intensity speeds. These may positively affect your iAnT if you have also been working your low intensity easy distance training. This step is necessary for long term increases in your speed at iAnT, and is often neglected by non-elite athletes.
It is easy to get caught thinking low lactate is better than high lactate. We are conditionned to fear “high lactate values” as we often associate buring muscles with lactate. Ironically, it is not lactate that causes the burn, but more probably the acidity levels (this revelation is often too much for many non-physiologists as it requires too much reprogramming of how we interpret training/racing discomfort and pain).
At low speeds you will alsways have lower lactate. However, to push yourself and race to your potential you do not do compete at your iAnT but ever so slightly above iAnT. How much above iAnT depends on the length of the race, how hard you’ve trained, and how hard you are able
to push yourself.
If you’ve worked on pushing your peak HR up near your physiological / genetic maximum, you will produce higher lactate. If you have never worked in that range, you won’t produce as much lactate, nor will you have as much speed reserve. This is one reason I hope never to be in a
sprint finish with a sprint trained athlete. if they kept up through the long portion of the race and it all comes down to the final few meters they may well have a bigger speed reserve than I do.
- i.e. in our local fun races on Tuesday nights some flatwater sprinters come out. One of them is on the Canadian junior national team. We race side by side for 4.9 of the 5 km (the bit at just over iAnT – so mostly aerobic fitness) then we start winding it up for the
finish. At this time, my peak speed was ~13.5 km/hr and his is ~15 km/hr (the anaerobic or high lactate producing portion).
Back to test interpretation, if your lactate values at a given HR are increasing and the associated speed does not change (or gets slower), you may have a problem. Poor nutrition resulting in muscle glycogen depletion could be the cause, or a loss of aerobic fitness. However, if you’ve been working the high intensity end of your training this is a normal result. If after an easy distance phase the associated speeds don’t increase you can assume a problem exists.
Fatigue or overtraining would probably result in a decrease in speed and lactate at a given HR. If it is overtraining (chronic fatigue), you can expect to take months to recover, while short term fatigue will clear up with a few days of recovery. Using indices of overtraining/fatigue monitoring tools will gove you more insight into this.
- Incidentally, a well designed training program should be designed around recovery as opposed to work. This will minimize the risk of overtraining.
There are a number of books to help you learn about lactate curves.
- Swimming Fastest: Ernerst Maglischo
The Science of Winning: Jan Olbrecht (coach of IM Hawaii record holder Luc VanLierde and advisor to top cyclist Jan Ullrich)
Lactate Threshold Training: Peter Janssen- lots of sample data from top athletes and long term follow up data showing training induced changes.
Check these out here
More excellent resource books are the Blackwell Scientific IOC Series with the Endurance in Sport book or the Power in Sport book being worth purchasing.
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