Changes

You can think of Critical Power can be thought of as a threshold between aerobic and anerobic anaerobic exercise. While that's an oversimplification, it reflects the subjective feelings of the athlete quite well. In some ways it's similar to the idea of like [[Lactate Threshold]], but far easier to determine. The idea of Critical Power has been around since 1965<ref name="MonodScherrer1965"/>, but the rise of power based cycling trainers, cycling power meters, and now the ability to estimate running power with [[Stryd]], the concept has gained new traction. Critical Power is the highest workload that you can be sustained sustain without using the anerobic your anaerobic reserve , and is research papers often considered the consider this workload that an athlete can be sustained sustain "indefinitely." In practiceOr course, "indefinitely" here means until glycogen reserves start to get depleted, or other limiting factors set in. Typically, so typically you can maintain Critical Power for 30-60 minutes can be maintained at Critical Power<ref name="Hill1993"/>. Above the Critical Power, there's an amount of work that you can be performed perform anaerobically. This anaerobic work capacity is typically called name W' (W-prime), and it . You can either be used use your W' at high intensity for a short period or a lower intensity for a longer period. This creates a curve of how long you can sustain a given high intensity power level can be sustainedabove Critical Power.[[File:CPModel_sience.png|center|thumb|400px|Critical power, from [https://www.goldencheetah.org/Golden Cheetah].]]

I see There are several benefits to knowing your Critical Power as a runner. Improvements in your Critical Power show improvements in your fitness. This is a good way of evaluating the effectiveness of your training. Critical Power can help define your running paces. To use Critical Power for pacing, you can't use your Critical Power when cycling directly. One option is to perform a Critical Power test while running, using [[Stryd]] (the greatest benefit from only running power estimation that works as of April 2020.) The other option is to convert your cycling power to your Stryd running power. You can use Critical Power for [[High Intensity Interval Training| HIIT]]. A You can structure an HIIT workout can be structured based on your CP and W', using those metrics . You can use these values to understand how stressful (and how practical) a given workout will be. I use Golden Cheetah which will show the W' balance as a curve for a given workout. The CP and W' can be used for pacing allow you to pace shorter races (30-60 minutes) as an . An ideal pace will be one in which you deplete W' is depleted evenly over the race, reaching near zero at the end. For longer races, other factors beyond W' depletion become the limiting factors, so it's less valuable there. However, CP can be used as a metric to evaluate for running potential (see below.)

The gold standard for measuring CP is to perform multiple tests to define points in the CP/W' curve. Each You need to perform each test needs to be performed while well recovered, so each needs to be on a separate day. After a warmup, you do a fixed power workout is performed that should result in cause your exhaustion between 3 and 15 minutes (durations less than 3 minutes may give an overestimate of CP<ref name="BishopJenkins2007"/>.) Given these results, there are a number of several online calculators that will give CP and W' numbers. (As an aside, one One study found that CP occurred at around 83% of [[Maximum Heart Rate| Max HR]] <ref name="MielkeHoush2011"/>). ==The 3AOT Approach==There's a simpler "3 minute all out test" (3AOT) that can estimate your CP. This is an test must be "un-paced" test where the athlete goes you go all out for the duration of the test. This means that power output will be very high for the first few seconds, then drop off as you deplete your W' is depleted. The idea is that by the end of the 3 minutesBetween 90 and 120 seconds, you should have depleted all of the your W' will be depleted and you can only the maintain your CP can be maintained. The limitation of the test is that any pacing by the athlete, even subconsciously , will overestimate CP and underestimate W'<ref name="Mandell2019"/>. There are several studies that have found the 3AOT gives a good estimate of CP/W'<ref name="BurnleyDoust2006"/><ref name="DekerleVanhatalo2008"/><ref name="VanhataloDoust2007"/>, and they . These studies found that it a 3AOT can detect relatively small changes in CP with from training (, such as increasing CP from 230-to 255w)<ref name="VanhataloDoust2008"/>. One validation technique that was a study used was to exercise at 15w above and then 15w below the critical power estimate. The study found the that athletes could not maintain 15w above could not be maintained past their CP for over 10-15 minminutes, where 15w below is their CP was stable from ~10 min up to 30 minminutes. However, one study found the 3AOT did not provide valid results in elite cyclists<ref name="BartramThewlis2017"/>, with . That study found that the 3AOT estimating estimated an average of 351w compared with 402w with multiple tests. This study found that the underestimated the athletes' W' was underestimated, with measuring an average of 15.5 kJ rather than 24.3 on averageKj.

A study looked at the relationship between Critical Power and Running Performance<ref name="KolbeDennis2008"/> over 40m, 1km, 10km, and 21.1km (half marathon distance.) The study found a reasonable correlation between CP and both running performance and [[VO2max|V̇O₂max]] for distances of 1km and longer. They found that CP corelated correlated with 75-85% of both values (r=0.75-0.85). =Critical Power and Power at V̇O2max=I find it interesting that Critical Power is halfway between [[Lactate Threshold]] and the maximum power attained during an incremental [[VO2max|V̇O₂max]] test<ref name="PooleBurnley2016"/>. This suggests that the power achieved at [[VO2max|V̇O₂max]] is partly from anaerobic sources.