Differentiating between the usual, "I just worked out really hard" pains, and the more worrisome, "I think I might've hurt myself" ones can be difficult, especially when you're trying to push yourself towards progress. "There's a pain of injury and a pain of adaptation—one is bad, and the other is good," says Equinox Advisory Board Member Justin Mager, Ph.D., a San Francisco Bay Area-based exercise physiologist and physician. Here's how to know the difference.
The Good Kind:
The comeback aches. "You might be doing an activity perfectly, but if you haven't done something like high-intensity cardio in a while, it's normal for your body to ache a bit during and after your session," he says.
1. The immediate aftershock. When you perform an activity pain-free, and then feel really sore afterwards, that's a good sign. "Pain after properly executed exercise means that your body is adapting to become more fit," says Mager. Note: Taking ibuprofren or other anti-inflammatories might slow down those fitness adaptations.
2. (Perfectly normal) soreness. Your soreness could last anywhere from two to four days post-workout. Rather than stopping all movement and letting the pain take over during that time, you should work through it and keep your muscles moving instead, says Mager.
The Bad Kind:
1. Biomechanical error. "I had really bad left knee pain, and then an Olympic weightlifting coach taught me how to do squats differently. Now my knee feels better than ever," says Mager. "If you don't have any pain prior to your activity, and then you experience pain while you're performing a particular movement, you should take a step back and have a trainer evaluate your biomechanics."
2. Interconnected injuries. Any chronic, pre-existing pain in your back, hips, or knees might rear its ugly head in other parts of your body, says Mager. "For example, an ankle issue will probably create knee issues. It's important to make those connections so that you can avoid misdiagnosis and focus your treatment appropriately."
3. Localized pain. "A repetition should not feel painful," says Mager. "Take a bench press, for example. If you're doing it right, both arms and chest are going to burn out together. But if you have discomfort in one area, it's muscular failure and a sign that something's off," says Mager. "If you're experiencing localized pain during or after strength training, it's a red flag."
4. Acute, out-of-nowhere aches. Any sharp, stabbing, traumatic, and/or sudden pains during any kind of workout should be checked out immediately.
5. The overdoing-it variety. If the pain lingers into your next attempted exercise session after your two-to-four day recovery period, you might be overtraining or not recovering adequately enough between workouts. "If you're doing maximal work, you need maximal recovery," says Mager.