LACTATE THRESHOLD

Lactate Threshold
http://www.hornetjuice.com/lactate-threshold.html

Everyone wants to ride, run and swim faster. Whilst natural ability still plays a huge role, lactate threshold is highly trainable (as is Vo2Max). By training properly almost every individual can ramp up their lactate threshold.

What is Lactate Threshold (also known as anaerobic threshold)?
Lactate is a by-product of anaerobic metabolism that, despite common misconception, is produced across all exercise intensities. In fact, even when you stand up from sitting in a chair, lactate acid is produced. The key in sport is the balance between the rate of lactate production and lactate absorption.

During light and moderate-intensity exercise, the blood concentration of lactate remains low. The body is able to absorb lactate faster than the muscle cells are producing it. However, as exercise intensity increases, there comes a point at which lactate removal fails to keep up with the rate of lactate production. This point is referred to as the lactate threshold and spells the beginning of the end of high intensity exercise.

Excessive blood lactate and hydrogen ion concentrations combine to interfere with efficient and proper muscle contraction, and as a result, power output drops, suffering increases and you are forced to slow down.

Lactate threshold represents the highest steady-state exercising intensity an athlete can maintain for prolonged periods of time (> 30 minutes).

Most coaches and sport scientists today recognize lactate threshold, or a derivative thereof, as one of the strongest predictors of endurance performance.

Lactate Threshold also serves as a very useful measure for the determination of training zones and the overall effectiveness of training programs.

How is Lactate Threshold Measured?
Lactate threshold tests typically are performed on a treadmill or bicycle ergometer. After an adequate warm-up period, the test starts at an exercise intensity corresponding to 50-60 percent of the test subject's VO2MAX. Each stage lasts 2-6 minutes, allowing sufficient time for the subject to achieve steady-state heart rate, VO2, and lactate production. Blood samples taken towards the end of each stage determine blood lactate concentration (a simple finger prick does the trick). The workload increases in steps and the process is repeated until an obvious spike in lactate concentration occurs. Heart rate, power output or speed, and/or VO2 are recorded at each stage.

We measure blood lactate concentration in millimoles (mM) of lactate per liter of blood (mmol/L). Lactate threshold typically is expressed as a percentage of one's VO2MAX or maximal heart rate. With the advent of power meters, various power outputs identify a riders lactate threshold and training zones. By evaluating a rider's power output at lactate threshold, we can determine the potential for success. To be competitive in a race like the Tour de France, a male professional must be able to maintain 5-6 watts/kg at lactate threshold. This means if the rider weighs 68 kg (150 lbs) he must produce 350-400 watts while riding up even the toughest hills.

If you take two cyclists, one with a high VO2max but a moderate lactate threshold, and the other with a moderate VO2max but a ridiculously high lactate threshold. Being the same size and weight, the cyclist with the highest lactate threshold would likely find himself victorious in a head to head race up a monster hill.

How to determine Lactate Threshold (LT)
http://www.trainingpeaks.com/hunter/thresholdwattage.asp

Lactate Threshold Test for Power for Beginner to Intermediate Athletes

• Get in 25 minutes in your warm up before starting the test. During warm up, get in 1 x 5 min all out Time Trial effort after 15minutes of your warm-up and spin easy until you get in the full 25 minutes. It's important that in each month in which you test, your warm-up is the same. Do this test somewhere that you can come back and re-test each month.

• On a loop, or out and back, on the flats or rolling hills (so you get the wind in all directions), give me your best 20 minute effort. Don't start too hard, build up in the first 1-2 minutes and then get right to your edge and get into the fastest and most powerful rhythm you can maintain, and explode in the last minute, right at the finish. Be sure to get in an easy 20 min cool down to recover.

Lactate Threshold Test for Power for Advanced Athletes

• Get in 40 minutes in your warm up before starting the test. During warm up, get in 1 x 5 min all out Time Trial effort after 20 minutes of your warm-up and spin easy for 5 minutes. Then do (2) x 1 minute as hard as you can go with 2 minutes rest between each. Then just ride at a steady endurance pace until you get in the full 45 minutes. It's important that in each month in which you test, your warm-up is the same. Do this test somewhere that you can come back and re-test each month.

On a loop, or out and back, on the flats or rolling hills (so you get the wind in all directions), give me your best 20 minute effort. Don't start too hard, build up in the first 1-2 minutes and then get right to your edge and get into the fastest and most powerful rhythm you can maintain, and explode in the last minute, right at the finish. Be sure to get in an easy 20 min cool down to recover.