Effects of walking training at different speeds on body composition, muscle contractility, and immunocytes in the elderly: A single-blinded randomized controlled trial

Background: This study investigated the changes in body composition, muscle contractility and immunocytes of the elderly using three types of walking.Material and Methods: Seventy-six participants were randomly assigned to control group (CON), slow walking group (SWG), moderate walking group (MWG), or fast walking group (FWG). Results: Muscle mass in CON decreased (-2.55 +/- 3.63%; P < 0.05), while it increased in FWG (1.92 +/- 4.46%; P < 0.05). Fat mass in CON increased, whereas it decreased in MWG and FWG (-18.71 +/- 14.22%; P < 0.001). Tc (contraction time) of biceps femoris (BF) decreased in CON, while a decreasing tendency was seen in SWG. Although Tc of BF increased in MWG, it showed a marked increase in FWG (21.19 +/- 24.53%; P < 0.05). A similar tendency was observed in the rectus femoris. Leukocytes did not change in CON, but they showed an increasing tendency in MWG and FWG. Neutrophils decreased in CON, whereas the other groups showed an increasing tendency. Lymphocytes (10.25 +/- 19.48%; P < 0.01) and helper T cells (14.32 +/- 17.99%; P < 0.05) showed an increase in FWG, and NK cell was improved in SWG, but showed a clear increase in MWG (38.45 +/- 96.96%; P < 0.05) and FWG (52.69 +/- 58.37%; P < 0.05).Conclusions: This study concludes that fast walking by the elderly improves the muscle contractility, which can also be expected to improve the function of immunocytes by increased or maintained muscle mass and decreased fat mass after 12 weeks.