National Academy of Sports Medicine (NASM) Senior Fitness Specialist (SFS) 2025 – 400 Free Practice Questions to Pass the Exam

The decrease in the ability to produce quick, forceful contractions is primarily associated with the loss of Type II muscle fibers. Type II muscle fibers, also known as fast-twitch fibers, are crucial for explosive movements and high-intensity activities due to their ability to generate fast and powerful contractions. These fibers are designed for short bursts of strength and speed, making them essential for activities requiring rapid, forceful exertion.

As individuals age or undergo certain conditions, there can be a decline in the number and functionality of Type II fibers. This loss significantly impacts overall muscle performance, leading to a reduced capacity for quick reactions and explosive strength. Therefore, a reduction in Type II muscle fibers has a considerable effect on functional mobility and performance in seniors, highlighting the importance of maintaining muscle health through appropriate training and physical activity.

In contrast, an increase in Type I muscle fibers, thickening of ligaments, or shortening of tendons would not directly produce this effect regarding the rapid and forceful contraction capabilities of muscles. Type I fibers are more endurance-oriented, while changes in connective tissues typically do not impact the speed or force production of muscular contractions in the same way.