下图中显示为一位骑士先稳定地爬上一个小坡，然后在另一侧享受先前先做的功，快乐地自由溜下，最后回到平地又开始踩动踏版保持前进。爬过坡的车友们一定都有感，爬坡时心率和RPE（运动自觉强度）都会逐渐上升，气也越喘越大声，但是功率和速度则是保持在一个较稳定的状态，到了下坡时，速度则是节节飇升，而心率，RPE与功率都快速下降。若把曲线放一起看，其实可以看出心率的反应慢了几拍（与RPE相比图形略偏右），就连刚开始下坡时心率都还在上升，这样的延迟是很常见的事；RPE在爬坡时快速累积痛苦，下坡时也快速地回到舒适的感觉，直到最后进平地又开始踩踏为止；速率在爬坡时显然相对较低，下坡时飞快，平地时又回到一个稳定速率前进。
（出处：Joe Friel (2012). The Power Meter Handbook: A User’s Guide for Cyclists and Triathletes）
那功率呢？它即时地显示出另外三个资讯所发生的一些变化，稳定地爬完坡后，功率在两个切换点迅速地发生变化：停止踩踏开始下滑与进入平地开始踩踏时。可以明显地看出，功率曲线能即时地呈现运动员最真实的输出。
功率越高，运动表现当然越理想，同理在速度方面亦然。速度和功率直接反应出运动表现，而RPE和心率告诉你运动员正在经历的“情形”。当把心率、RPE与功率相比较，我们便能得知运动员的“体能水准”，当在同一个坡上时，能踩出更高的功率可是RPE与心率却相对降低，我们便可以很容易地知道这个运动员变强了！
输入与输出
前段中所提到的功率与速度表示运动表现，心率与RPE呈现运动中体验，这里指的其实是一个输入与输出的关係，这四个数据分别归类为两种“多少”：功率与速度是输出的测量方式，告诉我们到底输出了“多少”；而心率和RPE是输入，告诉我们为了制造这样的输出而花了“多少”。
这是很重要的区别，在竞技运动中，你将因为输出而获得奖赏（干掉对手，得到奬盃或第一个冲过终点线）；但是最努力的，可能有残酷的现实在等待。
（以上原文请见附录）
比较后才有意义
由上我们可以知道，心率和RPE在“比较”之后才能帮助我们获得资讯，如文中的例子，同样的功率输出，可是输入变少了（心率变低），这就是体能变强了，或是分析有氧区间和无氧区间之的心率变化，也可以得知自己在有氧能力或无氧能力哪一个比较需要加强，并针对自己的比赛项目做训练调整。所以若能有更多监测设备，可以帮助你得到更多训练资讯，有1+1>2的效果啊！不过看到那么多数据，又该如何整理和分析呢？别担心，请继续锁定本专栏啰！
附录
Notice that heart rate and RPE rise as the hill is steadily climbed, while speed and power remain fairly constant. When the rider is coasting down the hill, speed increases as heart rate, RPE, and power decline. Note that heart rate is slow to respond as the rider starts up the hill, and heart rate continues to increase in the early part of the descent. This lag is common with heart rate. RPE increases on the climb as fatigue gradually sets in. RPE rather quickly decreases on the downhill side before rising again as pedaling is resumed on flat terrain. Speed remains constantly low on the uphill, increases on the descent, and eventually settles in at a steady rate with the return to flat terrain.
Now look at the power line. It reflects some of the changes taking place in the other three, but it does so rather quickly. Following a steady level on the climb, power almost immediately responds to the transition from climbing to coasting and from coasting to pedaling on the flat section. The power line presents the most useful picture of the athlete’s performance because it is a direct measurement of the rider’s output.
The higher the power is up the hill and on the flat terrain, the greater the rider’s performance is. The same can be said of speed. Only power and speed are directly related to performance. Heart rate and RPE tell us nothing about performance—they simply reflect what the rider is experiencing. When compared with power, however, heart rate and RPE also tell us something about the rider’s fitness. When power is high and heart rate and RPE are relatively low compared with previous rides on that same hill, we know that the athlete is fitter and faster.
OUTPUT AND INPUT
“Only power and speed are directly related to performance. Heart rate and RPE tell us nothing about performance—they simply reflect what the rider is experiencing.”
What I’m describing here are output and input. Power and speed are measures of output. They tell us what is being accomplished during a ride. Heart rate and RPE are input. They tell us what the effort is to create the output.
This is an important distinction. Races give out awards based on output— who got to the finish line first. There are no awards for input—who worked the hardest to get there.
文/耐力网/曾奕颖
跑步入门指南//www.nduoke.com/beginners-guides
跑步入门文库//www.nduoke.com/beginners-articles
跑步入门秘诀建议//www.nduoke.com/beginner-tips
