We've always known weightlifting not only changes your muscles, but it can also change your brain and nervous system for the better. Now we may know why thanks to a new study from the United Kingdom.
Researchers at Newcastle University trained monkeys strength training exercises to study how weightlifting affects the brain. They found that repeated weightlifting changed the animals' brains before any muscles were added.
According to the study, published in June in the Journal of Neuroscience, researches found that repeated weightlifting strengthened the nervous system that delivers neural input to muscles.
“Strength isn’t just about muscle mass," co-author Isabel Glover, told the Inverse.com. "When you start lifting weights, you get stronger because the neural input to your muscles increases. It’s only a few weeks later that the muscles themselves start to get bigger."
A core finding of the researchers was weight training benefited the animals early on. Their nervous systems changed and could activate their muscles more efficiently, even before new mass was added.
A diagram of the contraption researchers used to study monkeys lifting weight
For three months, researchers trained two female macaque monkeys to pull a weighted handle with one arm 50 times daily and rewarded them with food. Over time, researchers increased the weight to a goal 6.5kg, the approximate bodyweight of the animal. Despite the physical difficulty and challenges with motivation, the animals reached the goal.
Beyond the physical training, researchers investigated the animals' nervous system and found an increase in strength in the reticulospinal tract (RST), shedding new light on how the brain, muscle mass and weightlifting are all connected.
"The results show that strength training first increases the strength of connections from the reticulospinal tract to the spinal cord, allowing muscles to be activated more strongly," Researcher Stuart Baker said to Inverse.com. "This happens early on — only later do muscles grow larger, which adds even more to the maximum strength."
The takeaway for humans, say the researchers is that if you don't have immediate strength results from training, keep at it. More is happening behind the scenes. Big changes are happening in your brain that could lead to big payoffs down the line.