## How To Run Faster With Critical Power Training For Speed Endurance

### Increase your speed endurance with critical power training.

The critical power or critical speed is defined as an intensity between steady state and non-steady state exercise. In simpler terms, it is the maximum sustainable intensity in which, food fuel availability is not a limiting factor. It is an excellent tool to monitor endurance performance but can also be used for prescription of training intensity. Critical power lies between the hard and severe exercise intensities. If we work above critical power, we will burn out our anaerobic work capacity and there is a finite amount of time before we will be exhausted and exercise intensity will have to be reduced. This concept is mainly applicable to sports where, we are continually working within a severe exercise intensity domain such as a 1500 m run or a 10 mile cycling time trial. There is a growing thought that in elite marathon runners, that critical power training could be used to make a race plan to break the 2 hour marathon.

THE VIDEO: How to Run Faster with Critical Power Training for Speed Endurance

#### How can we calculate critical power?

One way, is through a mathematical formula requiring the use of high tech equipment which, isn’t particularly accessible. However, there is an alternative. In its simplest form, critical power or critical speed is measured as mechanical work, distance and time. On 3 to 5 separate occasions, an athlete will run a distance for example, 1200m (264s), 1600m (330s), 2000m (410s), 4000m (900s) and so on. This distance will be completed as fast as possible with very little pacing. It isn’t pleasant. Each of these times will be plotted on a graph in Excel. Add in a line of best fit, regression line, and it will pop out an equation.

D = (CS·T) + D’

D = Distance (m), CS = Critical Speed (m^{-1}s^{-1}), T = Time (s), D’ = Anaerobic Running Capacity (m)

This example would be y = 4.30x + 154.5

If we re-arrange this formula we can work out the time it would take to do any distance at this critical speed. Then, all you need is a stopwatch and motivated athlete to be able to match these times.

Time to complete prescribed distance = (Distance – D’) / CS

Time = (5000m – 154.5) / 4.30

Time = 4845.5 / 4.30

Time to complete 5000m = 1126s

#### How can we use this value to be a better endurance athlete?

It is important to note that there are two aspects of improving critical power. These are speed at critical power and anaerobic work capacity.

To improve the speed at critical power we want to work above the critical power threshold for prolonged periods of time through high intensity interval training or continuous high intensity work. An example of this may be working at 105% of your critical speed for 1 minute with 30 seconds recovery, 6 times, two times per week alongside, traditional endurance and high intensity training. If we are working below the critical power, then, theoretically we will be able to exercise forever and this will elicit less of a benefit for critical speed despite improvements in VO^{2} kinetics and VO^{2} max. Activities that work to improve your VO^{2} max will help to improve your critical power but the most effective way is to work above the critical speed for sustained durations repeatedly.

To improve our anaerobic work capacity, we want to be working maximally. This could include maximal sprints of 4-10 seconds with 30-60+ seconds of recovery between each bout. This will predominantly use your anaerobic energy sources developing specific adaptive responses. If we can increase our anaerobic work capacity, then, we can work for longer durations above our critical power which, may be advantageous when it comes to a sprint finish at the end of a 5K.

Critical power is your maximal sustainable running, swimming or cycling intensity and is a useful tool to help prescribe exercise intensity. It requires you to be motivated to complete each test maximally but if you can get through this, then, you will be in a good position to improve your training and race runs. To improve this value, make sure you are working above critical speed and to increase your anaerobic work capacity make sure you are working beyond this intensity towards maximal.