Older adults tend to lose muscular strength because muscle cells
get larger in size.
attach to the nervous system.
increase in number.
get smaller in size.
The correct answer and explanation is :
Correct Answer:
Older adults tend to lose muscular strength because muscle cells get smaller in size.
Explanation:
As people age, they experience a natural decline in muscle mass and strength, a condition known as sarcopenia. This process is primarily due to the reduction in muscle fiber size (atrophy) rather than an increase in muscle cell number or a detachment from the nervous system.
Muscle atrophy in older adults occurs for several reasons:
- Reduction in Muscle Fiber Size:
- The two primary types of muscle fibers are Type I (slow-twitch) and Type II (fast-twitch). Aging particularly affects Type II fibers, which are responsible for powerful and quick movements. These fibers shrink in size, leading to reduced strength.
- Decrease in Motor Unit Recruitment:
- As people age, motor neurons (nerve cells that control muscle contractions) die or become less efficient. This leads to a decrease in the number of active muscle fibers, further reducing strength and coordination.
- Lower Protein Synthesis Rate:
- Muscle maintenance and growth require continuous protein synthesis. In aging individuals, protein metabolism slows down, meaning muscles regenerate and repair at a slower rate.
- Hormonal Changes:
- The decline in testosterone, growth hormone, and insulin-like growth factor-1 (IGF-1) affects muscle growth and regeneration. These hormones play a critical role in maintaining muscle mass, and their decrease contributes to muscle shrinkage.
- Lifestyle Factors:
- A sedentary lifestyle, poor nutrition, and lack of resistance exercise accelerate muscle loss. Older adults who engage in strength training and consume adequate protein can slow down or partially reverse muscle loss.
Conclusion:
Muscle cells get smaller in size as people age, leading to decreased strength. Regular physical activity, especially resistance training, along with proper nutrition, can help mitigate this process and improve overall muscle function.