Wednesday, August 28, 2013

Optimizing Running Training Part 1

This series will look at using Ventilatory Thresholds, Lactate Threshold and Annaerobic Threshold Training to optimize your run training  This will be a fairly lengthy discussion, so I have broken it up into several parts.

DEFINITIONS: Terms can become very confusing  

Lactate Threshold

Lactate threshold is a speed, or percentage of V.O2 max at which a specific blood lactate concentration is observed or the point at which blood lactate concentration begins to increase above resting levels
The maximal lactate steady state is defined as the exercise intensity at which maximal lactate production is equal to maximal lactate clearance within the body. The maximal lactate steady state is considered by many to be a better indicator of aerobic endurance performance than percentage of maximum heart rate.

Ventilatory Threshold
Ventilatory Threshold is the ‘point of transition between predominantly aerobic energy production to anaerobic energy production.’ And if you want to get specific…then the first ventilatory threshold is ‘the intensity at which ventilation starts to increase in a non-linear fashion’ and the second ventilatory threshold is a further change in the respiration ratio curve.

Lactate threshold and Ventilatory threshold are closely related but are not exactly the same thing.  Lactate threshold is difficult to measure, requiring blood samples immediately after or during an event.  Ventilatory threshold is much easier to measure and gives a practical indication of Lactate threshold for training purposes.

But how do we measure VT1 and VT2? Research has found that the Talk Test provides an accurate measure of the body’s response to increasing intensity. Where before we relied solely on percentage of heart rate (We’ll discuss heart rate monitor training in an upcoming post), now physiologists have discovered that talk test relates very well to similar intensities.

Below VT1: you can speak comfortably, recite the alphabet etc.
At VT1: you can no longer speak comfortably; it requires some effort at this point
Above VT1/Below VT2: speaking is possible, but not really comfortable, you can’t recite the entire alphabet with ease at this point
At VT2: Speaking is no longer possible with the exception of one or two word statements, chances are you are not going to be able to exercise much longer above this point‘’.

How to Optimize Your Endurance Training Using Lactate Threshold and Anaerobic Threshold

The purpose of this discussion will be to describe the physiological mechanisms behind the lactate, ventilatory, and anaerobic thresholds, as well as discuss the heart rate threshold.  This will be used to outline training principles for the improvement of lactate threshold values in your training.

Lactate Threshold and Endurance Performance
Traditionally, maximal oxygen uptake (VO2max) has been viewed as the key component to success in prolonged exercise activities However, more recently researchers have proposed that the lactate threshold is the best and most consistent predictor of performance in endurance events. Research studies have repeatedly found high correlations between performance in endurance events such as running, cycling, and race-walking and the maximal steady-state workload at the lactate threshold (McKardle, Katch, & Katch 1996).  This research is what we will use to optimize out training.

What is the Lactate Threshold?
At rest and under steady-state exercise conditions, there is a balance between blood lactate production and blood lactate removal.  The lactate threshold refers to the intensity of exercise at which there is an abrupt increase in blood lactate levels.
Lactate threshold effects involve the following key mechanisms:
1) Decreased lactate removal
2) Increased fast-twitch motor unit recruitment
3) Imbalance between glycolysis and mitochondrial respiration
4) Ischemia (low blood flow) or hypoxia (low oxygen content in blood)

Next: Metabolic Pathways Overview
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