落入凡間的科學怪人遊記

全文引用自wko+ user guid：

http://home.trainingpeaks.com/trainingpeaks-wko/wko-user-guide/workout-data/quadrant-analysis.aspx

原文與翻譯如下：

There is a lot of valuable information on this page.  To make it easier to read, we have it broken down into three parts, but it is recommended that you read through the entire thing to get an understanding of the Quadrant Analysis feature.  

翻譯：這很重要，請把它讀完

What is Quadrant Analysis?

Quadrant Analysis is a way to measure the neuromuscular power demands of cycling.  Taken from the book, "Training and Racing with a Power Meter by Hunter Allen and Dr. Andrew R. Coggan,  "Tools such as Normalized Power, Intensity Factor, and Training Stress Score explicitly recognize the seemingly stochastic nature of cycling power output and help coaches and athletes better understand the actual physiological demands of a given race or workout. Even so, to completely understand the physiological consequences of large variations in power, one must also understand how they impact neuromuscular function—that is, the actual forces and velocities that the leg muscles must generate to produce a given power output. Such effects are recognized by the algorithm used to calculate Normalized Power, but only to the extent that they influence metabolism (e.g., via altering fiber-type recruitment patterns). Although strength (or maximal force) per se is rarely a limiting factor in cycling, neuromuscular factors nonetheless can still sometimes play an important role in determining performance. Thus, we realized that it would be useful to be able to analyze power-meter data that captures this important information in a form that could readily be grasped even by nonexperts.

Neuromuscular What? “Neuromuscular function” may sound complicated, but it simply means how fast you can contract a muscle, how strongly you can contract it, and how long you can contract it before relaxing it again. When someone learns a new movement pattern—it could be anything from learning how to type on the keyboard to pedaling a bicycle—those movement patterns are governed by that individual’s ability to transfer the information from his or her brain to the muscles that are involved. We all take this for granted, and when it comes to cycling we just pedal, but in reality each of us is different in our ability to make these contractions occur. With your power meter, you can begin to understand your neuromuscular ability, and you can determine whether you are training correctly for cycling success and then begin to improve your neuromuscular power.

 翻譯：

什麼是象限分析？

象限分析是衡量自行車的神經肌肉輸出力量的一個方式，內容擷取自神書「Training and racing with power meter」，如同NP、IF、TSS這些工具一樣，能夠明確的解析看似隨機性的輸出功率，讓運動員與教練能夠明確的瞭解，實際比賽與訓練科目的生理需求，即便如此，為了要完全的理解大功率的變化對於生理產生的後果，以及瞭解這又如何影響神經肌肉的功能，也就是說，實際腿部肌肉的力量與踩踏速度，會產生一個特定的輸出功率。這會被用來計算NP，但是這些影響僅限於代謝能力（例如：改變肌肉纖維的合成模式）。雖然說強度（或最大力量）本身是一個自行車的限定能力，但是神經肌肉因子有時在運動表現中仍然是扮演重要的角色。也因此我們意識到這是一個很有用的重要訊息，透過功率計的數字，即便是非專業的人員也能輕鬆掌握。

神經肌肉什麼？“神經肌肉功能”可能聽起來很複雜，但它只是意味著你如何快速收縮肌肉，你可以承擔多麼強烈，以及多久可以收縮之前再次放鬆。當有人學習新的運動模式--------它可以是任何一樣東西，從輸入鍵盤到自行車踩踏-------這些運動模式的能力，從他或她的大腦的信息轉移到肌肉。我們以為是理所當然的自行車踩踏，其實現實中我們每個人都是不同的。透過功率計，你可以開始了解你的神經肌肉的能力，你能夠確定你是否正確的訓練，然後開始提高神經肌肉的力量

（看不懂嗎？很正常）

What are these units on the Y and X axis?

On the Y AXIS: The velocity of muscle contraction (as indicated by cadence) is only one of two determinants of power, with the other, of course, being force. Unfortunately, at present no power meter directly measures the force applied to the pedal. However, it is possible to derive the average (i.e., over 360 degrees) effective (i.e., tangential to the crank) pedal force (both legs combined) from power and cadence data. The equation looks like this:AEPF = (P*60)/(C*2*Pi*CL)

In this formula, AEPF stands for “average effective pedal force” (in newtons, or N); P is power, in watts; C is for cadence (in revolutions per minute); CL is for “crank length” (in meters); and the constants 60, 2, and pi serve to convert cadence to angular velocity (in radians/seconds). Additional insight into the neuromuscular demands of a race or training session can then be obtained by preparing a frequency distribution histogram for AEPF that is similar the one for cadence, as shown in Figure 7.3. (Note that, as with all such plots, graphs like this one do not take into consideration how long AEPF was continuously within a given “bin,” or range. This is not an issue, however, because unlike, for example, heart rate, neuromuscular responses and demands are essentially instantaneous. Indeed, it is the generation of specific velocities and forces via muscle contraction that essentially drives all other physiological responses.)

Although simply examining the frequency distributions of AEPF and cadence provides insight, it does not reveal the relationship between these two variables. This relationship can only be quantified by plotting force versus velocity.

翻譯：

Y軸：是踏板上的力度

On the X AXIS: Circumferential pedal velocity—that is, how fast the pedal moves around the circle it makes while pedaling—is derived from cadence as follows:CPV = C*CL*2*Pi/60

Here, CPV stands for circumferential pedal velocity (in meters/second); C is for cadence (in revolutions per minute); CL represents crank length (in meters); and the constants 2, pi, and 60 serve to convert the data to the proper units. Although technically, muscle-shortening velocity, or at least joint angular velocity, should be used instead of CPV, CPV has proven to be an excellent predictor of both of these. Indeed, since crank length is generally constant, especially for a given individual, one could just as well use cadence instead of CPV. However, we have used the latter here to be consistent with scientific convention and to emphasize the relationship of cycling-specific plots to the more general force-velocity curve of muscle. A scatterplot of force and velocity, such as that shown in Figure 7.4, therefore presents information that cannot be obtained from just frequency distribution plots of AEPF and CPV.However, it can be difficult to detect subtle and sometimes even not-so-subtle differences between roughly similar rides based on such “shotgun blast” patterns, especially if the scaling of the X and Y axes is allowed to vary. Furthermore, without additional information, such force-velocity scatterplots are entirely relative in nature because there are no fixed anchor points or values that can be used as a frame of reference. It is the latter issue that Quadrant Analysis was specifically developed to address.

翻譯：

X軸：是踏板的速度

How to use QA?

Using QA is as simple as clicking on the the Quadrant Analysis Tab on your workout View.   Understanding what it means is a different thing though!

Before we delve into the details of understanding them, we should point out the features inside the QA tab, so you can make sure you are interpreting them correctly.

Threshold: This should be the threshold that you set inside your Power Training zones on your Athlete Home page.  If this is not correct, you can change it here, by typing in a new Threshold value, or by Creating a new power zoneon your Athlete home page

Lo Threshold: this should be set at about 20-30 watts under your Threshold value, just to give you some perspective on the graph.

Hi Threshold: this should be set at about 20-30 watts above your Threshold value, again, to help you with some perspective on the graph.

T-Cadence: This is the Threshold cadence.  It's your normal self-selected cadence in which you would average when you do a threshold interval.

Crank Length: The Crank length of your cranks on your bike.

Centering the Axes- This is a somewhat hidden, but very easy and useful feature.  You can change the center of the axes, by just double clicking anywhere in the view.   Double-click in the upper right and it pulls the axes to the upper right.  Double-click to the lower left and it pulls the axes to the lower left.  Simple and can really help you read the chart more clearly.

翻譯：如何使用象限分析

請看下圖，Threshold就是你的FTP值，也就是黃線，Lo/Hi就是+/-20-30W，落在曲線上方的表示大於FTP的輸出，落在下方的就表示小於FTP的輸出，T-cadence則是你慣用的迴轉數，Crank Length 是曲柄長度，十字中心點則很好用你可以到處按兩下看看會發生什麼事。