A new study (Batista LH, Vilar AC, Ferreira JJA, Rebelatto JR & Salvini TF) has be published on the effect of stretching and it impact on fitness, specifically in application to older adults. Here is a brief overview of the important factors:
Deficits in muscle strength and range of motion are common in older adults but not to exclusive to, due to a decrease in overall flexibility. Reduced flexibility is generally caused by shortening and increased rigidity of muscles. These viscoelastic changes in muscle fibers have deleterious functional consequences, such as aberrant gait patterns, and hampered ability to rise from a seated position, leading to a greater incidence of falls and loss of independence.
Stretching is an exercise performed in clinical settings and physical fitness facilities used to increase range of motion. Research has shown that stretching can cause morphologic change in muscle fibers and connective tissue, ultimately leading to an increase in overall muscle strength.
Previous studies have shown that similar results can occur after a stretching intervention implemented every day for 6 weeks straight. This study showed that flexibility training twice a week for 4 weeks is as efficient as a 6 week training protocol
According to this group of researchers, it is conceivable that stretched muscles are stronger because both passive and active forces add to strength production. Previous research concluded that the increase in stored energy and ranges of motion after stretching is important because it can increase the elastic recoil capacity of a muscle. However, this notion is not completely agreed upon in the fitness industry.
Regardless, stretching is a vital component of fitness, equally so as cardiovascular endurance and muscular strength, which not only has benefits in its own right but improves all component of fitness.