Structural And Functional Relationships
As noted earlier, these data all define sarcopenia in terms of its compositional, rather than functional (strength) aspect. However, there are data suggesting that the decline in strength with age exceeds the decline in lean mass. Studies of change in muscle strength over time have shown declines, no change, or gains in strength over periods ranging from four to twenty-five years. A reduction in type II muscle fibers has been shown in some studies, but no change was found in others. In addition to the quantitative decline in muscle with age, there is a qualitative decline, with reduced force production by single fibers from elderly men compared to young men.