This is an antiquated theory I wholeheartedly subscribe to. However, nowadays, if most people hear these words, especially people who are experienced in fitness, they freak out! If they do, it’s my fault and I should be more clear.
When I would come home from college for the summer, I taught at tennis academies. Part of my teaching involved leading the conditioning sessions for the kids, most of whom were 12-18 years old, competitive tournament level players. However, many of them were also lazy, and needed to be pushed; that is why they were training and also why I led the conditioning. Sure, if one of them had an injury, they wouldn’t have had to participate in conditioning, but if they were too injured for that, they wouldn’t have come in to train that day in the first place. Kids would stop, and I would do everything I could to make them keep going.
When I say “no pain, no gain,” I refer to mental toughness. This is what you need to push yourself through a marathon or even when you are lifting. Obviously, you need to discern between physical pain and mental pain. However, a lot of what you need to achieve physical results is driven by how mentally fit you are.
Now, I am not suggesting that you train through an injury. That would be stupid, er, and something I might do, like I did in early January.
If I am sore from doing squats or dead lifts one day, I still go running the next. Yeah, soreness does not feel good, but I find that the cardio actually helps to get rid of the soreness. It is a kind of physical pain that I believe can be worked through.
Still, there should be a differentiation between an actual physical injury and mental toughness when people say “no pain, no gain.” There is a huge difference between when you are super fatigued and you push yourself to keep fighting on, vs. when you are hurt.
Unfortunately, a lot of people mistake feelings of fatigue with feelings of physical pain. So much of what we feel is mental, and when people realize this they can see much more in the way of physical gains. Those kids I taught all would get tired, but it was only the ones who realized that mental toughness could make them keep fighting who actually progressed further in their tennis careers. This is a lesson that anyone can apply and this is what I mean when I say “no pain, no gain.”