Written by John Donovan, PT, DPT

One of the things about being a physical therapist I enjoy is the daily variety it brings. After all, no injury is exactly like another. However, there are some consistencies. For example, almost everyday, I hear the phrase “No pain, no gain.” There is certainly a time and a place for the sentiments conveyed by this saying, but it generally isn’t my favorite thing to hear in the physical therapy clinic. 

Where did this phrase even come from?

The phrase in question has actually existed in slight variations for quite awhile. For example, around 700 BC the Greek poet Hesiod conveys the idea a little more elegantly writing, “before the road of excellence, the immortal gods have placed sweat” (Works and Days, c. 700 BC). Other early uses include those by Sophocles and Rabbi Ben Hei Hei. Generally, these authors are using the phrase in the context of some sort of life struggle.

Most of us, thanks to a number of more recent celebrity trainers and exercise enthusiasts, are probably more familiar with the use of this phrase in the context of exercising. And this is what I think most of the patients I hear this phrase from are trying to reference. However, the pain they are usually talking about is not the same pain our favorite Hollywood action stars are embracing to get their superhero physiques. What’s the difference? Let’s dive a little deeper into the science of pain. 

So what exactly is pain?

First of all, pain is a complicated and multifaceted topic. As a medical community, we are still learning about it. Pain is also uniquely personal. What is painful to someone could be an entirely different sensory experience to someone else. The rest of the discussion regarding pain is not meant to be an all encompassing guide to pain science. In fact, for the sake of keeping this post from turning into a textbook, some of the technical aspects of pain science will only be discussed briefly. Of course, if you have any specific questions you should reach out to your healthcare provider. Meriam-Webster defines pain as “a localized or generalized unpleasant bodily sensation or complex of sensations that causes mild to severe physical discomfort and emotional distress and typically results from bodily disorder (such as injury or disease).” The key thing to keep in mind as you keep reading is that pain is a “sensation or complex of sensations.” As pain relates to physical therapy, it’s generally the reason that people seek help from a physical therapist. When you go to a physical therapy clinic for your first session, you probably filled out a brief survey asking you about your pain and maybe whether or not you could perform certain tasks. Two of these questions likely went something like this: 

1. Describe the quality of your pain: aching, sharp, stabbing, numb, burning, shooting, etc.
2. Rate the intensity of your pain: 0 – 10

Now, no health care provider is going to put a ton of stock in your answers to either of these questions. However, they can give us some useful information, including in explaining why I’m often hesitant to reinforce the phrase “No pain, no gain.”

“Describe your pain…”

Let’s consider quality first. There are lots of variables that contribute to pain:

• Actual mechanical changes to the tissue around the injured area.
• Chemical changes to the injured area such as inflammatory markers and inflammation itself.
• Neurologic changes to nerves communicating information about the injured area to your central nervous system.
• Even changes within your central nervous system influencing your emotional response to the pain.

Each of these alone is worthy of several graduate level lectures, and this is where I’m going to make sure we don’t get too deep into the exact physiology. Many experts in the science of pain will describe these contributing factors as a “mosaic.” This term reflects the uniqueness of each pain experience as the factors resulting in the experience will vary. You may not realize this initially, but if you think back to any of your injuries or aches, you can probably tell that each one is a little different. For example, the pain in your shoulder that led you to physical therapy probably feels different than stubbing your toe. That shoulder pain has a specific quality to it that reflects the mosaic of factors leading to the specific pain you are feeling. If you’ve been through physical therapy before, your therapist may have even referred to this as “your pain.” 

Quality makes a difference

If you tell me “No pain, no gain” while doing a therapy exercise and you are talking about the same pain that brought you into therapy, I can almost guarantee you that I’ll stop you from doing that exercise every time. First of all, you may actually just be mechanically irritating the already inflamed tissue. Beyond the obvious, what this tells me is that something about that particular movement pattern is activating the same pain system – enhancing the mosaic if you will – that brought you to physical therapy in the first place. To understand why this is not necessarily something that should be worked through or toughed out, we need to look at sensory nerve anatomy a little more closely. 

Time for an anatomy lesson!

We often think of nerves as either on or off. However, with sensory nerves this really isn’t the case at all. In fact, these nerves are always firing at some baseline rate or frequency. A deviation from that baseline yields the experience of some kind of sensation. When you think about it, this makes a lot of sense with simple everyday experiences. Holding a hot drink on a cold day will cause nerves relaying temperature information to fire at an increased rate. However, those same nerves will fire at an even faster rate if you accidentally come in contact with the hot water used to prepare that drink leading to a decidedly less comfortable experience. 

Nerves are also highly adaptive. Staying with the temperature theme, imagine getting into a hot tub that’s just a little too hot. If you were to get in quickly (like you may do if getting into a cold pool) the water temperature is probably going to be pretty uncomfortable. But if you get in the way we learned to as kids (a few inches deeper every half minute or so), you give your nerves time to adjust. Every time you inch deeper, your nerves fire at a faster rate. But because you only exposed a few inches of skin to the hot water, they do not reach a rate that prompts you to withdraw. And as you leave your feet in the hot tub, eventually your nerves return to their baseline and you feel like you are used to the temperature. Moreover, this adaptation lasts for a short period. If you get out of the hot tub and then come back in a few minutes, you’ll find that it is easier to get in the second time around. 

“But wait, shouldn’t that mean that if I keep pushing through the pain eventually I’ll get used to it?”

Admittedly, that’s a good question and some of that does happen. However, I can tell you that in my experience, the people I meet who are used to pain are also always in pain. Consider a skilled movement, something like playing the guitar or driving a golf ball. If you wanted to get better at performing this skill, what would you do? Practice! Both of the aforementioned skills require quite a bit of repetition. Every time you do that movement, not only are you going to make the muscles that are involved stronger, but the nerves will begin to adapt as well, becoming more efficient at doing their role in the process. Given enough time, you will get better. 

The reverse effect for pain

However, this works against us when we talk about the nerves involved in your pain experience. Every time you feel pain, the nerves that relay information about the painful area to your brain and the nerves in your brain itself become more easily activated. The end result is this system is so good at working that it is almost always active and you are almost always feeling some kind of pain. This can even go as far as to create something pain scientists call allodynia: the experience of pain from stimuli that would not otherwise cause pain. Imagine water running over your hand being a painful experience. If it is possible to avoid building up the nerve systems responsible for communicating your pain, I would prefer to avoid it. 

(Now, there are certainly some exceptions to this and I think the most important is in cases of long lasting or chronic pain where this system has already been made so efficient you will probably feel a little pain/discomfort with most movements. But even in these cases, the exercises should still feel very manageable. See the following discussion on intensity.)

“Ok, that makes sense. But what about when I’m working out at the gym?”

Let’s circle back to pain quality, most of us would agree there is a certain type of discomfort that comes from exercising. It may not feel the same to all of us, but we can probably agree it is different than the kind of pain we would go see a physical therapist or doctor for. It isn’t your pain, but it is still telling you something about your body. When you are working out, you are actually causing microtrauma to your body. The loading of the tissues (muscles, tendons, etc.) that are helping you move is actually creating a little damage to them. Given appropriate time and resources to recover, your body will rebuild the areas of microtrauma and build them back stronger than they were before you worked out. 

Ok give me the final word

So if you say to me “No pain, no gain,” AND you can confirm that the pain you are referencing is different than “your pain,” great! Let ‘er rip! … within reason. This is where intensity comes in. For quite a few people, this likely will not come up in the clinic because by the time you are ready to exercise to this intensity, you’ve been done with physical therapy for at least a few weeks. When you are at the gym, however, it’s a different story. Muscle fatigue or burn within reason is very valuable. However, pushing too hard could put you at risk of an injury such as a muscle strain, and that could land you back in PT with me. For other people, especially those who have been experiencing pain for a longer period of time, it may be necessary to bend the quality rule a little. In these cases, your therapist should be able to help you figure out which exercises are ok to be a little uncomfortable and which ones should feel pretty good. Sometimes we may give you a number threshold, something like no more than a 3/10 on the pain scale, but this will vary a lot person to person. A more certain intensity rule is that you shouldn’t feel like your pain is getting worse as you do more exercise or “ramping up.” In my eyes, that’s often an indicator that the exercise needs to be adjusted or at the very least that it is time for a rest break. 

In summary, “No pain, no gain” is not a phrase to live by when you’re in the physical therapy clinic. There are different kinds or qualities of pain and if possible you want to avoid recreating your specific pain. When you can’t avoid doing so, make sure you keep it in check. And even if you’re feeling a good exercise burn on your third or fourth set at the gym, keep in mind that sometimes too much of anything can be a bad thing. Generally it’s better to finish your workout feeling like you could have done more than to regret doing what you did. If all those criteria are met, well… alright, No pain, No gain!