
WKO4: Stamina Overview
By Tim Cusick and Dr Andrew Coggan
Introduction to Stamina
Stamina in endurance sports is the ability to keep performing for a long period of time. All endurance sports require stamina, although some, such as Ironman distance triathlons, marathon running and long endurance events require more stamina than others. Developing peak physical condition results in endurance athletes having a high degree of stamina because their hearts, lungs and muscles are all functioning at a high level of efficiency. If you have stamina, you will be able to concentrate fully on your endurance performance, fatigue will be less of a factor.
Stamina in WKO4
In WKO4 Dr. Andrew Coggan has designed a new metric for tracking stamina. This metrics is defined as:
"Stamina: a measure of resistance to fatigue during prolonged duration, moderate intensity (i.e., sub-FTP) exercise. Units are percent of maximum, i.e., 0-100%, although most individuals will fall in the 75-85% range."
The purpose of the metric to track and analyze an athlete’s endurance fitness over time in an effort to better understand:
1. Response to training stimuli
2. Effectiveness of Training Dose
3. Athletes “readiness to perform”
Additional uses
1. Relationship to Vo2Max
2. Relationship to muscle fiber type
3. Relationship to FTP

Stamina and the Endurance Athlete
Resistance to fatigue during prolonged duration, moderate intensity exercise, which gives us the ability to work out at a particular moderate intensity for an extended amount of time. Whilst there are many factors that make up our stamina, V02 max, muscle fiber type and lactate threshold are the most important.
V02 max is the maximum rate of oxygen consumption measured during exercise. It is a measurement of our capacity for aerobic work and is a key determinant of endurance capacity during extended exercise. Studies suggest our endurance ability is largely down to genetics, but targeted training can increase maximal oxygen uptake.
Endurance athletes have shown important specialization of muscle fiber type and adaptation through myoplasticity. Myoplasticity refers to the capacity of skeletal muscles to change. Training can increase muscle mass and alter muscle fiber composition depending on the specifics of an athlete’s training. Let’s look at how endurance and strength training each change muscles in different ways.
Lactate threshold is the level of exertion at which lactate accumulates in the blood stream/muscles. If VO2 max can be seen as an upper limit for aerobic exercise, the lactate threshold determines how much of that 'aerobic' upper limit can be used. Training can have a favorable effect on lactate accumulation and when it occurs, which is associated with improved endurance performance.

The expression for stamina: Stamina
Note: Stamina is a "score" and can only be tracked for a specific time period, will not work are "history" at this moment.
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