Age-Related Decline in Strength as Decline Neurons

“What we have here is (a) failure to communicate,” said the Captain in the 1967 film Cool Hand Luke. This line rings true today as it relates to the failure of physiologists to communicate the mechanisms of muscle strength to the geriatrics community, where the lack of muscle strength observed in older adults holds high clinical significance. Similarly, there is a relative under recognition in the scientific community for the potential role of the brain’s failure to communicate with skeletal muscle as a central component of muscle weakness in older adults. For the better part of the last quarter century scientific endeavors have primarily focused on the role of muscle wasting (sarcopenia) in explaining strength loss in seniors [1], with relatively little attention paid to understanding the role of the nervous system despite calls for investigations of this nature from preeminent scientists more than 25-years ago [2]. Developing a detailed understanding of the brain, which is commonly referred to as “the final frontier of science”, is still in its relative infancy, but there are already several key observations that clearly attest to the power of the mind as it relates to muscle force production. For example, findings that training with mental imagery of strong muscle contractions increases muscle strength also implicates the brain and its ability to produce a descending command as a key mechanistic determinant of maximal voluntary muscle strength [3]. Collectively, these findings provide general proof-of-concept support for the nervous system, at times at least, being a limiting factor in muscle performance.

As the neurons controlling muscle fibers die off, those muscles grow weaker. Possibly exercising muscles might keep signals going to those neurons and keep them alive, staving off age-related cognitive decline.