As we age many factors limit our ability to move as quickly as we used to including disease processes, medications, neurological changes, balance impairments, and importantly weakness. Age related weakness is a major contributor to falls, less independent living, and lower quality of life in older adults. Age related muscle loss begins for most adults in their early 30s and can be significant. Untrained males can lose 1% of their muscle mass every year after age 30. Often a threshold is reached when enough muscle mass has been lost reducing our remaining muscular tissue’s ability to contract quickly (rate of force development). A recent study explored which factors may be at play.
Wrucke et al. and colleagues examined the nervous system and muscle’s contributions to age related changes in strength and power (J Applied Physiology. 2024). Authors compared quadriceps muscle strength and power three groups
- 31 young adults (23 y.o, 50% female)
- 82 older adults (70 y.o., 46% female)
- 16 very old adults (86 y.o., 56% female)
Each individual performed a seated knee isokinetic test to determine peak power at 14 different joint velocities. Authors also assessed the brain’s motor cortex and the nerve that supplies the quadriceps muscle (femoral nerve) for their contributions during these tasks. Interestingly, authors found nervous system changes did not explain differences in muscle power. One exception was a minor role in the older women studied. Instead, the muscles ability to contract was found to be due to the muscle itself. The study results indicate the muscle’s force output, largely influenced by its’ size, and speed of contraction (power) were most significant. As we have discussed in previous blogs, a muscle’s speed of contraction (power) or rate of force development can improved by heavy strength training and jump training.
Click Here to schedule your next appointment with the experts at MEND