We tend to have a “muscle-centric” view of the effects of ageing and inactivity on health and physical performance. But as this great new article by @orssattolucas and colleagues argues, sarcopenia is a disease of the whole motor system, not just our muscles. Ageing affects the entire system responsible for producing movement - from the brain and spinal cord to motor neurons, peripheral nerves, the neuromuscular junction, and finally - the muscle itself. This is likely why the loss of muscle mass alone doesn’t always do a great job of accounting for the much larger declines we see muscle function, like strength and power, and physical function with ageing. It's also one reason why modern definitions of sarcopenia place more emphasis on muscle strength and physical function, rather than just muscle mass. But I think this broader view also helps us understand why resistance training is such a critical intervention here. Because resistance training already trains the whole motor system. With every repetition, the brain generates a signal, the spinal cord and motor neurons transmit it, the neuromuscular junction passes it on to the muscle, and the muscle fibres ultimately contract and produce force. That’s why resistance training is not just about building muscle, but challenging the whole system responsible for creating movement. It’s also why resistance training can produce large (and more rapid) gains in strength, power, and physical function, even without measurable changes in muscle size. I totally agree with the shift away from a “muscle-centric” view of sarcopenia. But perhaps we should do the same with resistance training too.

Back in 1999, 3234 adults with prediabetes were enrolled in a 3-year Diabetes Prevention Program. They were randomly assigned to either lifestyle (exercise + diet + support), medication (metformin), or placebo arms. 21 years later, the lifestyle group had a 21% lower risk of multimorbidity, while the metformin group showed no statistically significant reduction. How we move, eat, and live now could impact our health for decades.

After 17 years, the ACSM just updated their resistance training guidelines. So, what's changed?

Can lifting weights slow brain ageing? Here, one year of moderate or heavy resistance training slowed functional brain ageing by ~1-2 years in older adults, based on brain “clock” models derived from resting-state fMRI. These benefits persisted for 12 months and appeared to reflect global improvements in whole-brain networks rather than isolated regional changes. What’s good for your muscles is probably good for your brain.