IOWA City, Iowa — It might seem counterintuitive to exercise your muscles when you’re trying to stop muscle pain, but a new animal study suggests there’s a method to such madness. University of Iowa researchers report that resistance or strength training activates androgen receptors that protect against chronic musculoskeletal pain. Even if you don’t currently have muscle pain, the team suggests that regular strength exercise could help prevent future muscle pain and problems.
People with back pain or osteoarthritis know all too well that exercise helps to make chronic pain more bearable. But there’s not much research on how resistance training helps with musculoskeletal pain.
To study the benefits of strength training, the researchers trained mice to climb a ladder with small weights attached to it. Regular ladder climbing helped increase front paw strength.
Next, the researchers injected a mild acidic solution that was supposed to cause muscle pain during exercise.
However, eight weeks of resistance training halted the development of muscle pain in both male and female mice. When muscle pain was present, the team observed that the ladder-climbing exercise would help relieve the pain — but only in male mice. In addition, exercise resulted in a transient increase in testosterone in male mice, but not in female mice.
In previous studies, researchers have found a protective effect between testosterone and pain. To test its role in muscle pain, researchers injected some mice with a drug that blocks androgen receptors. Animals receiving the androgen blocker experienced muscle pain. However, once the exercise-induced protective effect was in place, the mice were not bothered by the pain induced by the androgen blocker.
The results suggest that androgen receptors are needed to protect against muscle pain. Although the study was conducted in mice, it could lead to more recommendations for strength or resistance training in people with chronic pain.
The study is published in Pain, the official journal of the International Association for the Study of Pain.