What I’ve Changed My Mind About: Strength and Pain
Muscular strength is one of the biggest themes in rehab. Weak muscles are often blamed for pain - weak glutes or core for low back pain, and weak shoulder muscles for neck pain or poor posture. The logic seems straightforward: if weakness causes pain, then getting stronger should fix it.
That’s certainly what I believed early in my career. I assumed strength was the main driver of recovery. But over time, and after reading more research, I changed my mind. People often improve while doing strengthening exercises, but those improvements aren’t consistently explained by increases in strength. If it isn’t strength that’s making people feel better, what else is changing?
Strengthening exercises are prescribed for many painful conditions, and they often work. But the literature has repeatedly found that improvements in pain don’t always line up with improvements in strength. For example, tendinopathies of the Achilles, knee, and shoulder often see improvements without meaningful changes in tendon structure or strength. Those with either general knee pain or knee osteoarthritis can see improvements in their pain and function without the surrounding muscles drastically improving. This growing body of evidence has led me to change my wording around the use of strengthening exercises - often people get better with strengthening, but it’s not necessary in order to get better.
Exercise changes much more than muscle strength. It can reduce tissue sensitivity, improve confidence in movement, reduce fear around pain, improve cardiovascular fitness, improve sleep and overall health, and gradually expose the body to the demands you’re returning to. Strength is just one adaptation among many.
It’s important though to make the distinction between rehab for pain and rehab for physical performance and return to sport. Strength still matters in injury rehab. Following ACL reconstruction, the research suggests that quadriceps strength needs to be at least 90% compared to the unaffected side; otherwise, the risk of re-tear increases. For baseball players, there are a couple of different metrics in shoulder strength to aim for in order to maintain a healthy arm. Strength is important in this context, but rehab for pain is not the same as rehab for performance; pain cannot be reduced to just, “get stronger.”
I still want my patients to get stronger. I just no longer assume that getting stronger is the reason they improve, or even needed to improve. I used to present exercise as the way to get stronger in order to get out of pain. Now I present exercise in a much broader sense. Exercise is a way to stay active despite injury and pain, increase activity tolerance, reduce fears around movement and pain, and restore confidence to return to sport and activity. This doesn’t mean strength doesn’t matter. It just means that pain is more complicated than strength alone. Strength gains are often one of the outcomes of good rehab, but not necessarily the reason it worked.
Reference:
Powell J, Wood L, Cashin AG, Lewis JS. It is not all about strength: rethinking mechanistic assumptions in exercise-based rehabilitation for musculoskeletal pain relief. Br J Sports Med. 2026 Mar 17;60(6):407-409.
