Muscle firing rates differ less by sex in older adults
An observational study compared young, middle-aged and older adults, linking older age to less adjustment of muscle-control signals as force increased.
Limit: Older adults were less physically active, which could contribute to differences in firing rates
Edited by Boris Djordjevic · AgingResearch.News
An observational study in young, middle-aged and older adults compared the firing patterns of motor units—a nerve cell and the muscle fibers it controls. Researchers recorded electrical signals from muscles and assessed muscle size and daily physical activity.
Women had higher average firing rates than men in the young and middle-aged groups at 30% of the strongest contraction participants could produce. This difference was absent in older adults. No sex differences appeared at 50% contraction strength in any age group. Firing rates fluctuated more in women. Older adults showed less adjustment of firing rates as contraction force increased. They also had lower daily physical activity. The authors suggested that physical activity may contribute to the age-related differences and emphasized strategies tailored by sex to preserve nerve and muscle function.
Why it matters
Understanding sex differences in nerve and muscle aging may help guide strategies to preserve muscle control with age.
Caveats
These observational comparisons cannot establish whether lower physical activity contributed to the differences. The abstract does not report participant numbers or age ranges.
- Physical activity
- Synaptic transmission
- Daily physical activity
- Maximal torque
- Maximal voluntary contraction
- Humans
The paper
Politecnico di Torino
npj Aging, Jun 29, 2026, Open access
