Take your pick of cliché statements from motivational posters. In order to improve athletic performance, you have to exceed your previous limits to induce new change. But by how much do you need to exceed those limits? Put another way, how much should it hurt? The stimulus for growth can come from time, intensity or frequency of training. This is only the stimulus. Real growth occurs during recovery as the body responds to the stresses that were placed upon it in an attempt to gird itself against future assaults. If the stimulus imposed is too drastic, or rest is inadequate, you will overwhelm the body’s ability to respond and adapt.

In this article, we’ll take a look at this response on both the micro and macro levels.

Starting small, what should your daily workouts feel like? There is clearly a vast difference between an endurance workout and an intensity session. At low intensities, fuel availability is often the primary limiter. If you persist long enough, muscular fatigue may set in, but it’s likely that in most cases you’ll become bored before this point. An endurance ride should not feel “hard,” but at the same time, it is not necessary for the ride to be completely easy. A good rule of thumb for finding the proper intensity is your ability to converse. If you are able to speak in full sentences, you’re in the right range. Apart from the contact points, there should be little soreness or muscular fatigue at the end of an endurance ride. With appropriate rest and refueling, these can be repeated daily for several consecutive days or even weeks. At the other extreme, high intensity efforts are limited by fuel availability, as well as rate of breakdown and muscular fatigue.

Here, there will be some pain. Muscles will burn and your lungs will ache at times, often during the workout and sometimes after the workout. When paced appropriately, you should not be suffering at this level for the entirety of every interval. At the start of a long interval (20 minutes for example), you should not be suffering to hold target power. If you are, the likelihood that you’ll be able to hold this power for the duration of the interval or reproduce it on subsequent intervals is low. On shorter efforts (a set of 5x1 minutes), the first interval may not feel very hard, but fatigue may start to creep in during the last few seconds of the second interval and by the final interval you may have real doubts about your ability to even get power into your target range, but you should be able to do so. Some workouts are, by their nature, not intended to be maximal. Tempo and Sweet Spot workouts are intended to overload the body a little bit, but in a way that reserves some energy and allows recovery to happen more quickly. Even for threshold and VO2 workouts that are intended to challenge your limits a bit more, it’s not necessary to completely drain yourself in each session.

Finishing with “something left in the tank” is often a good strategy. Completely exhausting yourself not only takes a lot of physical effort, but a lot of mental energy. Particularly at times when you find yourself riding really well, it becomes even more important to be judicious in how you dole out power, because you want to save that ability for your key events. If you don’t have any on the horizon, maybe you should find some and capitalize on good form when you have it. Moving on to the bigger picture, how should you feel between workouts and over several weeks of training? The standard advice is to allow a rest or easy day between each intensity session. This allows the quality of the intensity work to be higher, thus producing a greater stimulus that can lead to greater growth.

However, it’s often the case that even with recovery, there is some cumulative fatigue that is transferred from workout to workout. You still may be able to complete workouts, but notice it becoming progressively more challenging to achieve your targets over the course of a week or several weeks. This cumulative fatigue is a valuable part of training and not something to be avoided. Block training with multiple consecutive days of long and/or hard training takes this concept to the extreme. It is important to recognize when you get close to the tipping point and allow yourself a chance to recover and rebuild. A complete rest day once a week will often help to accomplish this. A reduced-load, recover week every 2-3 weeks is also a wise option. Many athletes resist this feeling, thinking that they will lose ground. However, once you reach the point when you can no longer achieve target powers, your muscles are chronically sore and your attitude becomes irritable, you’re no longer doing yourself (or anyone else) any favors. Providing the opportunity to recover allows the body to super-compensate and come back stronger after the break. This is how improvement happens. So to return to our opening question, how much should it hurt? At times, quite a lot. Individual workouts should be somewhat to extremely challenging at least once, and often twice, a week. But cases wherein large amounts of fatigue, soreness or disinterest are carried through several workouts should be monitored closely with appropriate opportunities for recovery given when the “hurt” starts to get the upper hand. Training should mostly be fun after all!